The Body’s Cellular Defense Network
See it. Understand it. Explore the Science.
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What is happening inside our bodies when cells encounter injury, inflammation, oxidative stress, and other everyday biological challenges?
The IMMA Visual Learning Series was created to make these complex processes easier to understand through scientific visualization, simple narration, and links to trusted research.
We begin with one central image: a symbolic representation of the body’s cellular defense network.
The DNA, cellular environment, inflammatory activity, oxidative stress, GSH, Nrf2 and nitric oxide shown throughout this series are used to help visualize biological concepts that can otherwise be difficult to imagine.
The images are educational visualizations—not literal representations of every molecular event. Each chapter explains what the imagery represents and provides scientific sources for those who want to explore the biology more deeply.
The Image That Started the Journey
This image was created to bring several complex biological concepts into one visual story.
It represents cells facing stress and damage while multiple protective and regulatory systems work to maintain cellular balance.
Rather than presenting inflammation or oxidative stress simply as “good” or “bad,” this series explores why these processes exist, how the body responds, how protective mechanisms interact, and what can happen when normal balance or resolution is disrupted.
Our Educational Approach
IMMA Visual Learning Series is developed to help make complex biological processes easier to understand.
The concepts explored throughout this series are informed by peer-reviewed scientific research, published medical literature, and other reputable scientific sources. We use visual storytelling and simplified explanations to illustrate mechanisms that can otherwise be difficult to visualize.
Scientific understanding continues to evolve. For this reason, relevant research studies and scientific references will be provided throughout the series for viewers who wish to explore each subject in greater depth.
These visualizations are educational representations. They are designed to help explain scientific concepts and should not be interpreted as literal representations of every molecular or cellular event.
Educational Information — Not Medical Advice
The information presented by IMMA is intended for general educational purposes only. It is not intended to diagnose, treat, cure, or prevent disease, nor is it intended to replace professional medical advice, diagnosis, treatment, or ongoing medical care.
Do not discontinue or change prescribed medications, treatments, or medical care based on information presented in this series. Questions about personal health, symptoms, medications, or treatment decisions should be discussed with a qualified healthcare professional.
PART 1 — THE BODY’S CELLULAR DEFENSE NETWORK
A Visual Introduction to Oxidative Stress, Inflammation & Cellular Defense
Understanding What You Just Saw
This opening video is a visual introduction to the IMMA Cellular Defense Network series. It uses DNA and the surrounding cellular environment as symbols to illustrate something happening continuously throughout the body: cells encounter stress, respond to potential damage, activate protective mechanisms, and work to restore biological balance.
The visualization brings together oxidative stress, inflammation, glutathione (GSH), Nrf2 and nitric oxide (NO). These are not one single defense system, and they do not perform the same functions. Rather, they represent different but interconnected biological processes involved in cellular protection, signaling, adaptation and homeostasis.
The dramatic imagery should therefore not be interpreted as a literal molecular event. It is a visual framework that will allow us to examine each mechanism separately in the videos that follow.
Now Let’s Explore the Science
The opening video introduces five interconnected areas of biology that will form the foundation of this series:
Inflammation • Oxidative Stress • Glutathione (GSH) • Nrf2 • Nitric Oxide (NO)
These are certainly not the only mechanisms involved in cellular defense, immune function or human health. Our biology involves an extraordinary network of cells, proteins, enzymes, signaling molecules, metabolic pathways and regulatory systems working together.
IMMA has chosen to concentrate this series on these five areas because extensive scientific research has explored their roles—and the important relationships among them—in cellular defense, redox regulation, inflammatory responses and cellular signaling.
A Network — Not Five Separate Systems
One of the most important ideas represented by the video is interaction.
Oxidative stress and inflammation can influence one another. Reactive oxygen species (ROS) are not simply harmful molecules that the body needs to eliminate. At physiological levels, reactive species participate in normal cellular signaling and immune responses. Oxidative stress develops when the production of oxidants and the body’s ability to regulate them become sufficiently imbalanced to disrupt normal redox biology and potentially contribute to cellular damage.
Inflammation should not automatically be viewed as an enemy either. It is an essential protective response involved in defending the body against infection and responding to injury and other harmful stimuli. Normally, inflammatory responses are carefully regulated and eventually move toward resolution. Problems can arise when inflammatory activity becomes excessive, persistent or improperly regulated.
Glutathione — More Than a Simple Antioxidant
Glutathione (GSH) is one of the major intracellular components of the body’s antioxidant and redox systems.
It participates in maintaining cellular redox balance and provides reducing capacity used by glutathione-dependent enzymes to help manage reactive molecules. GSH also participates in detoxification processes and has important relationships with normal immune function.
Research also shows why describing glutathione simply as a molecule that “fights free radicals” does not capture its full biological significance. Experimental research, including studies involving macrophages, has examined how intracellular glutathione status can influence aspects of innate immune and antiviral signaling.
Nrf2 — Activating Cellular Defense Responses
Nrf2 adds another layer to this network.
Unlike glutathione, Nrf2 is not an antioxidant. It is a transcription factor—a protein capable of influencing the expression of genes.
When cells encounter certain forms of oxidative or electrophilic stress, Nrf2 signaling can activate the expression of numerous genes involved in antioxidant defense, detoxification and other cytoprotective processes.
Importantly for our visual story, some of the systems regulated through Nrf2 are involved in glutathione synthesis, utilization and regeneration.
This provides one example of why cellular defense should be viewed as an interconnected network rather than as isolated molecules working independently.
Nitric Oxide — A Signaling Molecule
Nitric oxide (NO) is different again.
NO is a small, short-lived biological signaling molecule produced enzymatically within the body. It participates in numerous physiological processes, including regulation of vascular tone, cellular communication and aspects of immune function.
Certain immune cells can also generate nitric oxide as part of antimicrobial defense.
Its biology is highly dependent on context—including where it is produced, how much is produced and the surrounding cellular environment. For this reason, nitric oxide should not simply be described as either “good” or “bad.”
The Central Idea: Balance, Communication and Regulation
The important message of Part 1 is therefore not that one molecule or pathway controls our health.
It is balance, communication and regulation.
Our cells continually encounter metabolic activity, environmental exposures and other biological challenges. At the same time, multiple protective and regulatory systems are constantly responding, communicating and adapting.
The DNA, colors, energy and characters shown in the IMMA visualization are symbolic representations of this remarkable biological activity.
The characters are fictional. The biology they represent is real.
For Deeper Understanding
The following publications provide scientific background for concepts introduced in Part 1.
Oxidative Stress, Inflammation and Antioxidant Defense
This scientific review explores relationships among reactive oxygen species, oxidative stress, inflammatory processes and antioxidant defense systems. It provides useful background for understanding why oxidative stress and inflammation are often interconnected rather than completely separate biological events.
https://pmc.ncbi.nlm.nih.gov/articles/PMC12469104
Glutathione and Innate Immune Signaling
Experimental macrophage research has investigated glutathione beyond its familiar antioxidant role, including its relationship with innate immune and antiviral signaling. This research helps illustrate why GSH biology extends beyond the simplified idea of merely “neutralizing free radicals.”
https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2017.01239/full
Inflammatory Responses and Inflammation-Associated Disease
This review examines the biological mechanisms involved in inflammatory responses and helps distinguish the essential protective purpose of inflammation from the potential consequences of excessive or unresolved inflammatory activity.
https://pmc.ncbi.nlm.nih.gov/articles/PMC5805548
Nitric Oxide, Antimicrobial Defense and Biofilms
Research into nitric oxide demonstrates another dimension of this cellular network: NO functions as a signaling molecule and can participate in antimicrobial processes, while its biological effects depend strongly on concentration, location and cellular context.
https://www.mdpi.com/2076-2607/12/12/2543
These studies do not suggest that GSH, Nrf2, nitric oxide or any single biological pathway determines health or prevents disease. Rather, they help us understand some of the many interacting mechanisms the body uses to respond to its environment and maintain cellular function.
This is the foundation of The Body’s Cellular Defense Network.
In Part 2, we look more closely at what happens when oxidative stress and inflammation enter this cellular network—and how the body’s protective systems respond.
Oxidative Stress, Inflammation & Our Cellular Defenses | IMMA Part 2
Understanding What You Just Saw
Part 2 moves our visual story into a more challenging cellular environment.
The animation follows a symbolic DNA structure as reactive activity increases, protective mechanisms continue responding, and signs of cellular damage gradually become more visible.
This does not mean that oxidation or inflammation is automatically harmful. In fact, one of the most important ideas behind this visualization is that both are part of normal biology.
The question is balance.
Now Let’s Explore the Science
Reactive Molecules Have Normal Biological Roles
Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are continually generated through normal biological processes.
At controlled levels, these reactive molecules participate in cellular signaling, metabolism and immune defense. Cells therefore do not simply attempt to eliminate every oxidant. Instead, they continually regulate their production, activity and removal.
This controlled biological environment is part of what scientists describe as redox homeostasis.
When Balance Becomes Oxidative Stress
Oxidative stress occurs when redox balance becomes sufficiently disrupted that oxidant activity overwhelms or interferes with the systems responsible for maintaining normal cellular function.
When excessive oxidative activity persists, important cellular components can be affected, including lipids, proteins and DNA.
This is what the increasing damage in our animation is intended to symbolize.
The visualization should not be interpreted as showing the exact molecular sequence by which DNA or other cellular structures are damaged. Rather, it helps us visualize the biological consequence of a cellular environment in which protective and regulatory systems are struggling to maintain balance.
Where Does Inflammation Fit?
Inflammation adds another important layer.
Inflammation is an essential protective response involved in immune defense, responding to injury and supporting healing. Oxidative and inflammatory processes, however, can influence one another through multiple signaling pathways.
Reactive species can participate in inflammatory signaling, while activated immune cells can themselves generate reactive oxygen and nitrogen species as part of normal defense.
When these processes become persistent or poorly regulated, the interaction between inflammatory activity and oxidative stress can contribute to an increasingly challenging cellular environment.
This is why IMMA does not describe oxidation or inflammation simply as the enemy.
Their biological effects depend on regulation, intensity, location, duration and context.
Immune Activation Does Not Automatically Mean Oxidative Stress
This distinction is important.
A large meta-analysis examining 141 studies, 1,262 effect sizes and 97 vertebrate species investigated relationships between immune responses, infection and oxidative status.
The findings demonstrated associations between immune activity and changes in oxidative markers, but they also showed why immune activation should not automatically be equated with oxidative stress.
The body’s response is more complex.
Different immune challenges, tissues, species, biomarkers and biological circumstances can produce different redox responses.
This reinforces the central idea represented throughout the IMMA series:
Biology is about regulation and context—not simply labeling a biological process as “good” or “bad.”
There Can Also Be Too Much Reduction
Redox balance has another fascinating dimension.
We commonly hear about oxidative stress, but researchers also study reductive stress—conditions in which the cellular redox environment shifts excessively toward a reducing state.
This is important because reactive molecules themselves participate in normal signaling. Attempting to remove or suppress all oxidative activity would therefore not represent normal physiology.
Both oxidative and reductive disturbances can interfere with normal redox signaling and cellular homeostasis.
Once again, the objective of our cellular systems is not simply:
More antioxidants = better.
The biological objective is appropriate balance and regulation.
For Deeper Understanding
Redox Regulation of the Immune Response
Cellular & Molecular Immunology (2022)
This review brings together many of the mechanisms represented symbolically throughout our visual series. It examines relationships among ROS and RNS, glutathione, Nrf2, nitric oxide, mitochondria, metabolism and immune-cell function.
It is particularly useful for understanding why these mechanisms should be viewed as an interconnected regulatory network rather than isolated defense systems.
https://www.nature.com/articles/s41423-022-00902-0
A Meta-analysis of Impacts of Immune Response and Infection on Oxidative Status in Vertebrates
Conservation Physiology (2022)
This large meta-analysis examined 141 studies, 1,262 effect sizes and 97 vertebrate species.
Its importance to our visual story is the nuance it provides: immune responses can influence oxidative status, but immune activation does not automatically produce oxidative stress in every biological situation.
https://academic.oup.com/conphys/article/10/1/coac018/6564147
Redox Imbalance in Inflammation: The Interplay of Oxidative and Reductive Stress
Antioxidants (2025)
This review adds an important dimension to our discussion by examining both oxidative and reductive stress.
It helps demonstrate why maintaining redox homeostasis is considerably more complex than simply increasing antioxidant activity or attempting to eliminate reactive molecules.
https://www.mdpi.com/2076-3921/14/6/656
The Question That Takes Us to Part 3
If inflammation can contribute to a challenging cellular environment, an obvious question follows:
Why would our own body deliberately create inflammation?
The answer changes the way we think about inflammation.
NEXT — PART 3
INFLAMMATION EXPLAINED:
THE PROTECTIVE ROLE
Why inflammation exists, how it helps defend and protect us, and what can happen when a normally protective response becomes persistent or dysregulated.
Going Beneath the Surface
In the video above, we used a familiar experience—a minor impact followed by a bruise—to introduce something far more complex happening beneath the surface.
The video gives us the visual story.
Here, we are going deeper into the biology.
Because inflammation involves many interacting processes, Part 3 is divided into sections. We will follow the response from the moment tissue is injured, through cellular signaling and immune-cell recruitment, and eventually toward repair and resolution.
The purpose is not to memorize every molecule or pathway. It is to understand the remarkable sequence of events our bodies coordinate when something goes wrong.
Section 1 — Why Would Our Body Deliberately Create Inflammation?
Inflammation is frequently discussed as though it were simply something harmful that should be eliminated.
But that misses an essential part of the story.
Acute inflammation is one of the body’s normal protective responses to tissue injury, infection and other biological challenges.
Imagine the minor impact represented in our video.
Some cells may be stressed or damaged. Small blood vessels can be disrupted. The normal environment surrounding the cells has changed.
The body now faces several problems.
What happened?
Where did it happen?
How extensive is the damage?
Is there a potential infectious threat?
What needs to be removed?
And what needs to be repaired?
The inflammatory response helps coordinate the answers.
Rather than being a single event, inflammation involves communication among damaged tissue, resident immune cells, blood vessels, circulating immune cells and numerous signaling molecules.
This is why redness, warmth, swelling and discomfort are only the visible or perceptible parts of a much larger biological process.
Section 2 — How Does the Body Know Something Has Been Damaged?
This is where the story becomes especially interesting.
Damaged or stressed cells can release or expose molecules that normally would not appear in the surrounding extracellular environment in the same way.
Scientists often refer to some of these signals as damage-associated molecular patterns, or DAMPs.
They can include molecules originating from different parts of damaged cells.
Nearby cells and components of the innate immune system possess molecular sensing systems, including pattern-recognition receptors (PRRs), capable of recognizing signals associated with tissue damage as well as signals associated with microorganisms.
Recognition helps initiate cellular signaling.
In simple terms:
Something has changed → the change is detected → signals are generated → a response begins.
Our cinematic visualization compresses an extraordinarily complicated molecular process into only a few seconds.
The real biology involves networks of receptors, signaling pathways, cytokines, chemokines and other mediators communicating across many different cell types.
Section 3 — Cytokines & Chemokines: How Cells Communicate
Once damage has been detected, the response must be coordinated.
Cells use signaling molecules called cytokines to communicate and influence the activity of other cells. Chemokines, a specialized group of cytokines, are particularly important in helping guide immune cells toward areas where they are needed.
These signals are not simply signs of inflammation—they are part of the body’s normal protective communication network. Their timing, location, intensity and regulation help determine how the response develops and eventually moves toward resolution.
Damage has been detected. Now the cells need to communicate.
Section 4 — Why Do the Blood Vessels Respond?
Once inflammatory signaling begins, the local circulation becomes an important part of the response.
Blood vessels are not simply pipes carrying blood past the damaged area.
The cells lining those vessels—the vascular endothelium—participate actively in inflammatory signaling.
During acute inflammation, local vascular changes can increase blood flow and alter vascular permeability. Endothelial cells can also express molecules that help circulating leukocytes interact with the vessel wall.
These changes help create the conditions that allow immune cells and plasma components to reach affected tissue.
This contributes to some of the classic features associated with acute inflammation, including redness, warmth and swelling.
What appears externally as a swollen or discolored area therefore reflects only part of a coordinated response occurring at the microscopic level.
Section 5 — The Arrival of Immune Cells
Among the important early cellular responders to many forms of acute tissue injury are neutrophils.
Neutrophils circulate in the bloodstream, but inflammatory signals can help guide them toward affected tissue.
Their role can be extremely valuable.
Neutrophils possess powerful mechanisms for responding to microorganisms and damaged material. They can engulf particles, release antimicrobial substances and participate in clearing the affected environment.
But those powerful mechanisms also explain why inflammatory responses need careful regulation.
A response strong enough to defend tissue can also contribute to additional tissue injury if it becomes excessive or continues longer than necessary.
This is one of the recurring themes of inflammation biology:
The response must be powerful enough to protect—but controlled enough to limit unnecessary collateral damage.
Section 6 — Macrophages: More Than Cellular Cleanup
Macrophages are another important part of this story.
Some macrophages already reside within tissues, while additional monocytes can enter affected areas and differentiate into macrophages.
Macrophages can recognize cellular debris, microorganisms and signals produced within the inflammatory environment.
They participate in phagocytosis—the engulfment and removal of material.
But describing macrophages simply as cellular garbage collectors greatly understates their biological importance.
Macrophages participate in signaling throughout different phases of inflammation and can change their functional programs as the tissue environment changes.
During later stages of a successful acute inflammatory response, macrophages become particularly important in clearing cells that are no longer needed and helping create conditions that favor resolution and tissue repair.
Section 7 — Clearing the Battlefield
Neutrophils are extremely useful during the early inflammatory response, but they are not supposed to accumulate indefinitely.
After completing their functions, many undergo a controlled form of cell death called apoptosis.
These dying cells must then be removed.
Macrophages can recognize and engulf apoptotic cells through a process known as efferocytosis.
This is more sophisticated than simply disposing of cellular waste.
Research indicates that efferocytosis can influence macrophage behavior and the surrounding signaling environment, helping move the response away from continued inflammation and toward resolution.
The same immune system that helped initiate the response therefore also participates in bringing that response under control.
Section 8 — Resolution: Inflammation Doesn’t Simply “Turn Off”
This is one of the most important concepts in the entire IMMA inflammation series.
It would be easy to imagine inflammation like a fire:
Something starts it, the body fights it, and eventually the fire simply burns out.
Modern research presents a more sophisticated picture.
Resolution of inflammation is an active and coordinated biological process.
Additional neutrophil recruitment must be limited.
Cells that have completed their roles need to be removed.
Inflammatory signals need to change.
Macrophages and other cells adjust their activities.
Damaged tissue must begin rebuilding.
The local environment gradually moves toward restoration of normal function and homeostasis.
The body’s goal is therefore not simply to create inflammation.
The larger objective is:
detect → respond → protect → clear → repair → resolve.
Section 9 — When a Protective Response Becomes a Problem
This distinction helps us understand why inflammation can appear contradictory.
How can inflammation protect us while also being associated with disease?
Because acute, appropriately regulated inflammation and persistent or dysregulated inflammation are not the same biological situation.
A temporary inflammatory response to an injury can contribute to protection, cleanup and repair.
But if inflammatory activity fails to resolve appropriately—or the underlying stimulus continues—the biological environment changes.
Persistent inflammatory signaling can contribute to continuing tissue stress and damage and is associated with many different disease processes.
That does not mean inflammation itself should simply be viewed as the enemy.
It means that regulation and resolution matter.
This brings us back to one of the central ideas of the IMMA Visual Learning Series:
Biology is about balance, communication and regulation.
Explore the Science Behind Part 3
The explanations above are simplified for learning. Readers who want to go deeper can explore the scientific literature behind the concepts represented in our visualization.
Inflammation — Nature’s Way to Efficiently Respond to All Types of Challenges
Frontiers in Medicine
This review examines inflammation as an adaptive response to biological challenges. It discusses vascular changes, recruitment of leukocytes, phagocytosis and the subsequent down-regulation of the response associated with healing.
Why we included it: It provides a broad scientific foundation for the central message of our video—that inflammation has an important protective purpose and should not automatically be characterized as harmful.
https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2018.00316/full
Release Mechanisms of Major Damage-Associated Molecular Patterns
Cell Death & Disease / PubMed Central
This review examines damage-associated molecular patterns (DAMPs), including molecules released from stressed or damaged cells, and how these signals can interact with receptors involved in immune and inflammatory responses.
Why we included it: It helps answer one of the questions created by our video: How can the body recognize that tissue has been damaged?
https://pmc.ncbi.nlm.nih.gov/articles/PMC8016797
Targeting Neutrophils for Promoting the Resolution of Inflammation
Frontiers in Immunology
This review describes acute inflammation as a localized host-defense response to pathogens and tissue injury and examines the important roles of neutrophils. It also explores why neutrophil activity must eventually be controlled and cleared for successful resolution.
Why we included it: It helps explain both sides of the neutrophil story—their important protective functions and why continued or excessive neutrophil activity can contribute to tissue injury.
https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2022.866747/full
Resolution of Inflammation: An Integrated View
EMBO Molecular Medicine / PubMed Central
This review examines resolution as an active biological program rather than simply the passive disappearance of inflammation. It discusses limiting further neutrophil recruitment, neutrophil apoptosis, macrophage clearance of apoptotic cells and restoration of tissue homeostasis.
Why we included it: It supports one of the most important lessons of Part 3:
Inflammation doesn’t simply need to begin appropriately—it also needs to resolve appropriately.
https://pmc.ncbi.nlm.nih.gov/articles/PMC3662311
Resolution of Acute Inflammation and the Role of Resolvins in Immunity, Thrombosis and Vascular Biology
Circulation Research / PubMed Central
This review examines mechanisms involved in resolving acute inflammation, including neutrophil apoptosis, macrophage efferocytosis, clearance of damaged material and preparation of tissue for repair and regeneration.
Why we included it: It helps connect several stages represented throughout our visual story—immune-cell recruitment, cleanup, resolution, repair and eventual return toward homeostasis.
https://pmc.ncbi.nlm.nih.gov/articles/PMC5260827
THE JOURNEY SO FAR IN PART 3
The bruise in our video was only the doorway into the story.
Beneath something as ordinary as a minor injury can be an extraordinary sequence of biological events involving cellular detection, signaling, vascular responses, immune-cell recruitment, clearance, repair and resolution.
And there is much more to explore.
In the sections and videos that follow, we will continue going beneath the surface—examining these mechanisms individually and then reconnecting them to the larger cellular defense network.
See it. Understand it. Explore the Science.
IMMA — Immunity Matters
Understanding the Science Inside Us
CYTOKINES & CHEMOKINES
How Cells Communicate During the Protective Response
Damage has been detected—but recognition alone cannot coordinate a protective response.
Cells need to communicate.
Cytokines and chemokines are part of an extraordinary molecular communication network that helps cells exchange information, coordinate immune activity and direct cellular movement.
These molecules are sometimes discussed primarily in connection with inflammation and disease. But that can obscure something fundamental: cytokines and chemokines are normal and essential components of immune communication.
Their biological effects depend not simply on whether they are present, but on which signals are produced, where they act, their concentration, timing, duration, and how those signals are regulated and eventually resolved.
Understanding that balance is important before exploring what can happen when inflammatory signaling becomes excessive, prolonged or otherwise dysregulated.
CYTOKINES & CHEMOKINES
Going Deeper Into the Body’s Communication Network
The visual you just watched ended with an important transition.
The body had already detected that tissue was damaged. But recognizing damage is not enough. Cells must communicate with one another, coordinate what happens next, and help determine where additional support is needed.
This is where cytokines and chemokines become especially important.
They are part of an extraordinarily complex communication network that allows cells to influence the behavior of other cells. They help coordinate immune activity, inflammatory responses, cell movement and, importantly, the return toward tissue balance and resolution.
They are sometimes discussed mainly in connection with inflammation and disease. But that can give us an incomplete picture.
These signaling molecules are also fundamental components of normal immune communication and protection.
Research describes cytokines as important mediators of immune communication. Under normal conditions, cytokine signaling helps coordinate host defense and maintain tissue homeostasis. Problems can arise when cytokine production or regulation becomes excessive, deficient or imbalanced.
That distinction is central to understanding inflammation:
The presence of cytokines does not automatically mean something has gone wrong.
The body needs cellular communication.
The important questions are: Which signals are being produced? Where? In what amount? For how long? Which cells are receiving them? And is the response being appropriately regulated?
What Are Cytokines?
Cytokines are small signaling proteins produced by many types of cells.
One useful way to think about them is as biological messages.
A cell detects something happening in its environment. In response, it may produce and release particular cytokines. Those cytokines can interact with receptors on other cells—or sometimes the same cell—and influence what those cells do next.
Depending on the cytokine, cell and biological context, the message can help promote or limit inflammation, influence immune-cell activation, affect cell differentiation or recruitment, and participate in maintaining tissue homeostasis.
This is why describing all cytokines simply as “inflammatory molecules” would be misleading.
Some cytokine signals help initiate and strengthen protective responses. Others contribute to regulating or limiting those responses. Their effects also depend heavily on biological context.
The body is not simply turning inflammation on or off.
It is continuously coordinating signals.
Why would the body need this communication?
Imagine an area of tissue has been injured.
One cell detecting damage cannot repair an entire area by itself. Information has to spread through the local environment. Nearby cells may need to alter their activity. Blood vessels may need to respond. Immune cells may need to be recruited. Later, inflammatory activity must be reduced and tissue repair supported.
Cytokines are among the signals that help make that coordination possible.
That is why their normal role comes before our discussion of what happens when cytokine signaling becomes dysregulated.
What Are Chemokines?
Chemokines belong to the broader cytokine communication system, but they have a particularly fascinating role.
The term comes from their ability to influence chemotaxis — directed cellular movement in response to chemical signals.
The 2025 Frontiers review describes chemokines as relatively small secreted proteins whose hallmark function is inducing and guiding the directional movement of cells, particularly leukocytes—white blood cells.
For an everyday visual analogy, imagine an emergency has occurred somewhere in a large city.
Knowing that an emergency exists isn’t enough.
Responders also need information that helps them determine where to go.
Chemokine signaling can contribute to that biological direction-finding system.
During inflammation, chemokines can help orchestrate leukocyte trafficking toward sites of injury or infection. Different immune cells express different combinations of chemokine receptors, making the real system much more sophisticated than simply “follow this signal.”
So for our visual-learning purposes:
Cytokines help coordinate the conversation.
Chemokines are specialized cytokines that are particularly important in helping organize cellular movement and positioning.
That is a simplification—but a useful starting point.
More Than Calling Immune Cells to an Injury
Here the biology becomes even more interesting.
It would be easy for us to end the explanation by saying:
Chemokines attract immune cells.
But that would leave out an important part of their biology.
The Frontiers review explains that chemokines participate not only in leukocyte recruitment during the beginning of inflammation, but also in immune-cell positioning, homeostatic processes and mechanisms involved in resolution of inflammation.
Resolution is not simply inflammation running out of energy or switching itself off.
It is an active, coordinated biological process.
As inflammation resolves, continued recruitment of inflammatory cells must be controlled. Cells and debris need to be cleared. Signaling patterns change, and tissue repair mechanisms become increasingly important. The review describes several ways the chemokine system participates in these transitions and emphasizes the importance of balancing inflammatory and pro-resolving signals.
That connects directly with the larger IMMA visual story:
Detect → Respond → Protect → Clear → Repair → Resolve
The communication system changes as the biological task changes.
Why Balance Matters
This may be the most important concept in this section.
When people hear that elevated inflammatory cytokines are associated with disease, it can be tempting to conclude:
“Cytokines are bad, so fewer cytokines must be better.”
The biology does not support such a simple conclusion.
The 2026 cytokine overview describes cytokines as necessary for normal host defense and tissue homeostasis while also explaining that excessive, deficient or imbalanced cytokine production can contribute to pathological inflammatory processes.
There is even research illustrating why simplistic assumptions can fail. A 2024 pilot study examining chronic painful polyneuropathy expected inflammatory cytokines and chemokines to be elevated. Instead, several measured cytokines and chemokines were lower in cerebrospinal fluid in the patient group. The authors discussed several possible explanations—including the possibility that some of these mediators may have protective roles related to nerve regeneration—but emphasized important limitations and the need for further research.
That study does not establish that low cytokines cause chronic pain. It does something more useful for our educational purpose: it demonstrates why biology cannot reliably be reduced to “more inflammation molecules = worse; fewer = better.”
Context matters.
So rather than asking whether cytokines are good or bad, a better question is:
Is the communication appropriate for what the body needs at that moment?
The type of signal, location, concentration, timing, duration, target cell, and mechanisms that regulate or terminate signaling can all influence the biological outcome.
When Communication Becomes Dysregulated
Later in this series we will explore what can happen when this communication network becomes poorly regulated.
Some situations can involve excessive or prolonged production of inflammatory cytokines. Others may involve inadequate signaling, altered receptor responses, failure to transition toward resolution, or an inappropriate mixture of signals.
At the extreme end, uncontrolled systemic cytokine release can contribute to severe inflammatory syndromes sometimes described as cytokine storms. But that extreme example should not define how we think about cytokines themselves. Cytokine signaling is first and foremost part of normal biology; dysregulated signaling is the problem we need to distinguish from normal protective communication.
For IMMA, we will therefore explore the normal protective system first.
Only after we understand what these molecules are designed to accomplish will we examine what happens when their signaling becomes excessive, prolonged, insufficient or otherwise dysregulated.
🔬 Explore the Research
1. Special Issue: The Role of Cytokines in Disease
International Journal of Molecular Sciences, 2026
This article provides an especially useful starting point because it describes cytokines as mediators of immune communication and explains their roles in immune-cell activation, differentiation, recruitment, host defense and tissue homeostasis. It also introduces the other side of the story: excessive, deficient or imbalanced cytokine production can contribute to inflammatory dysfunction.
Read the full cytokine article
2. Chemokines in the Resolution of Inflammation: Key Players and Targets for Therapeutic Modulation
Frontiers in Immunology, 2025
This review takes us deeper into chemokines. It explains their classical role in directing leukocyte movement while also examining their involvement in immune-cell positioning, resolution of inflammation, tissue repair and restoration of homeostasis.
Read the full chemokine review
An important IMMA principle
Cytokines and chemokines are not simply “good” or “bad.”
They are part of the body’s communication system.
Their protective value depends on appropriate signaling, at the appropriate place, for the appropriate amount of time — followed by appropriate regulation and resolution.
NEXT IN THE IMMA VISUAL LEARNING SERIES
CYTOKINES — The Cellular Messengers
How can one cell send a biological message—and how does another cell know what that message means?
CYTOKINES — WHEN A CELL RECEIVES THE SIGNAL
From Cellular Communication to Cellular Response
In the previous section, we discovered that cytokines are part of an extraordinary communication network used by cells throughout the body.
But sending a message is only half of communication.
Another cell must be able to receive it.
Cells are surrounded by many different molecular signals. Yet they do not respond equally to every signal around them. One important reason is that cells carry specialized proteins called receptors that allow them to recognize particular signals.
Think of the cytokine as carrying biological information and the receptor as part of the system that allows a cell to recognize that information.
But what happens when the two meet?
Watch the Visual Explanation
UNDERSTANDING WHAT YOU JUST SAW
The visualization you just watched represents something happening throughout our bodies that we normally cannot see: cells communicating with one another.
When tissue is injured or cells become stressed or damaged, detecting that change is only the beginning. Once a potential problem has been recognized, information needs to be shared and the response needs to be coordinated.
One important way cells accomplish this is through signaling molecules called cytokines.
Cytokines are small proteins that can be released by many different types of cells. They act as biological messengers, allowing cells to influence the activity of other cells—or, in some situations, the same cell that released the signal.
But cytokines should not simply be thought of as “inflammatory molecules.”
They are part of a much broader communication system involved in normal immune defense, coordination between cells and the maintenance of tissue homeostasis.
The important question is not simply:
“Are cytokines present?”
A more useful set of questions is:
Which cytokines are being produced?
Where are they being produced?
Which cells are receiving their signals?
How strong is the signaling?
How long does it continue?
And how is that response being regulated?
These questions help us understand why cytokines cannot accurately be classified as simply “good” or “bad.”
Their biological effects depend on context.
CYTOKINES — CELLULAR MESSENGERS
Imagine that several different teams are responding to an emergency.
Detecting that an emergency exists is important—but detection alone is not enough.
Information must be exchanged.
Different responders need to know what is happening, where assistance is needed, when to act and eventually when the response needs to change.
Our cells face a similar challenge.
Cytokines help provide part of this biological communication.
Once released, cytokines can travel through the local environment and interact with cells capable of recognizing their signals. Through this communication, cytokines can influence processes such as immune-cell activation, differentiation and recruitment.
This is one reason cytokine signaling is so important during inflammation.
The inflammatory response is not simply a collection of cells arriving independently at an injured area.
It is coordinated biological communication.
CHEMOKINES — COMMUNICATION WITH DIRECTION
Among this enormous family of signaling molecules is a specialized group known as chemokines.
Chemokines are particularly important in helping organize the movement and positioning of cells.
During an inflammatory response, immune cells may need to leave the bloodstream and travel toward an area of injury or infection.
But how do those cells know where they are needed?
Chemokines contribute to this process by creating chemical information that cells equipped with appropriate chemokine receptors can detect and respond to.
This process is associated with chemotaxis—directed cellular movement in response to chemical signals.
A useful way to remember the distinction is:
Cytokines help coordinate the conversation.
Chemokines are specialized cytokines particularly important in helping organize cellular movement and positioning.
But even this is a simplification.
Research increasingly shows that chemokines are not involved only in recruiting immune cells during the beginning of inflammation. Chemokine signaling can also participate in normal immune-cell positioning, tissue homeostasis and the coordinated processes involved in resolving inflammation.
That connects directly with something we have been learning throughout Part 3:
Inflammation does not simply switch ON and then switch OFF.
The response changes over time.
COMMUNICATION MUST CHANGE AS THE RESPONSE CHANGES
Early after injury, biological communication may help recruit cells and organize protective activity.
Later, the needs of the tissue change.
Continued recruitment may no longer be beneficial. Damaged material needs to be cleared. Repair processes become increasingly important. Signaling patterns change as the tissue moves toward restoration of homeostasis.
This is why resolution is an active biological process, rather than simply the absence of inflammation.
The communication network itself must be regulated.
That gives us an important IMMA principle:
Cytokines and chemokines are not simply “good” or “bad.”
They are part of the body’s communication system.
Their biological effects depend on the signal, its location, timing and duration, the cells receiving it, and how the response is regulated.
WHEN COMMUNICATION BECOMES DYSREGULATED
A communication system is useful only when it is appropriately controlled.
Cytokine signaling that is excessive, insufficient, prolonged, poorly timed or otherwise dysregulated can contribute to abnormal inflammatory processes.
But this is different from saying that cytokines themselves are harmful.
The same biological systems that help protect us can become problematic when their regulation changes.
This distinction is important because discussions about inflammation sometimes focus almost entirely on reducing inflammatory molecules.
Biology is more complicated.
The body needs inflammatory signaling when it is appropriate.
It also needs mechanisms that regulate, modify and eventually resolve that signaling.
So instead of asking simply:
“How do we stop inflammation?”
A more biologically meaningful question is:
“How does the body create an appropriate protective response—and how does it regulate that response as conditions change?”
NOW LET’S GO ONE LEVEL DEEPER
We now understand why cells need to communicate.
But communication creates another fascinating question.
A cytokine can move through the environment surrounding our cells.
It may eventually encounter another cell.
Yet that cell is surrounded by a membrane separating its internal environment from the outside world.
So how does the cell receive the message?
The answer begins with specialized proteins called receptors.
And this takes us directly into our next IMMA Visual Learning lesson:
CYTOKINES — WHEN A CELL RECEIVES A SIGNAL
How can a biological signal outside a cell influence what happens inside it?
That is where I would put the second video.
Then after the second video, we go deeper again—but this time into receptors → recognition → signal transduction → intracellular signaling → cellular response and use the JAK–STAT research as an example rather than implying every cytokine uses that pathway.
EXPLORE THE SCIENCE
Under the first video section, I would retain the two studies we already selected because they answer two different parts of what the reader just learned.
1. Khaiboullina S. (2026) — The Role of Cytokines in Disease
This recent overview helps establish the broader biological role of cytokines. It describes cytokines as key mediators of immune communication involved in immune-cell activation, differentiation and recruitment. Importantly for our discussion, it also explains that under normal conditions cytokines contribute to host defense and tissue homeostasis.
That helps us understand why the presence of cytokines should not automatically be interpreted as something harmful. What matters is how signaling is being used and regulated within its biological context.
Read the full open-access article — PubMed Central
2. Oliveira, Proost & Struyf (2025) — Chemokines in the Resolution of Inflammation
This review takes us beyond the common description of chemokines as molecules that simply “call immune cells” to an inflammatory site.
The authors discuss chemokines as regulators of leukocyte trafficking and positioning while also examining their roles during the resolution of inflammation. This is especially important for our Part 3 journey because it reinforces the concept that resolution is coordinated and active rather than inflammation simply disappearing.
Read the full review — Frontiers in Immunology
NEXT IN THE IMMA VISUAL LEARNING SERIES
CYTOKINES — WHEN A CELL RECEIVES THE MESSAGE
We have seen how cells can use cytokines to communicate.
But sending a message is only the beginning.
How does another cell recognize that message—and how can a signal outside the cell influence what happens inside?
Next, we follow the message to the receiving cell.
See it. Understand it. Explore the Science.