Cytokines (Search and Destroy) Response to Pathogen Infection YouTube Lecture Handouts

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Cytokines (Search and Destroy) Response to Pathogen Infection | Cytokine Storm | Covid-19

Title: What Are Cytokines? What is Cytokine Storm

What Are Cytokines

1st responder to pathogen infection

  • Cytokines are molecules that allow your cells to talk to each other, and are crucial for healthy immune system function. Too many cytokines, however, can have a negative effect and result in what՚s known as a “cytokine storm.”
  • These small signaling molecules are produced by many different immune cells, such as neutrophils (some of the first cells to travel to an infection site) , mast cells (responsible for allergic reactions) , macrophages, B-cells and T-cells. Endothelial cells, which are the cells lining the inside of blood vessels, and epithelial cells, which are the cells covering the surface of organs, skin and other tissue, can also send cytokines around the body.
  • They then bind to specific receptors on both immune and non-immune cells, and may signal the cell to adjust how it grows or behaves. Nearly every organ of the body contains cells with cytokine receptors.
  • Chemokines are cytokines that act like a beacon directing immune cells where to go. In this way, chemokines help immune cells find and destroy whatever harmful invader has entered the body.

Get Activated! Alert!

How Cytokines Function?

  • When a pathogen, or harmful invader enters the body, immune cells, cytokines and organs respond by working together like an orchestra, Ford said. The first immune cell to notice the pathogen is like the conductor. That cell directs all the other cells by creating and sending out messages (cytokines) to the rest of the organs or cells in the body (the orchestra members) , which then respond as directed.
  • One of the immune response՚s cytokines may elicit is inflammation. Cytokines help inflame tissue by directing the cell walls of blood vessels to become more porous by reducing cell-to-cell contact. Blood vessels will then leak blood into the surrounding tissue, allowing immune cells to travel via the leaked fluid to the damaged area, and start the healing process.

Cytokines and Immune System

Response is slow? Why? Benefits?

  • Amount and type of cytokines that cells secrete differ depending on the type of pathogen, and those differences help the immune system appropriately tailor its response to be innate or adaptive. Certain cytokines can stimulate either the innate immune system, adaptive one, or a mix of both depending on the infection.
  • Cytokines can also direct brain cells to release chemicals that tell your body that you՚re sick, prompting you to rest and avoid activities that could further expose you to pathogens. Tiredness, lethargy, malaise and just that kind of achy feeling is the impact of cytokines on our bodies.
  • Without cytokines, the innate immune system wouldn՚t know when to activate because there would be no indication of a threat. Once activated, innate immune cells don՚t secrete cytokines intended for any specific receptors at first; secreted cytokines will target the entire body, causing fever, achy joints and fatigue.
  • The adaptive immune system will eventually secrete specific cytokines that target and activate T-cells in order to fine-tune the immune response toward the specific introduced pathogen.
  • Cytokines signal the adaptive immune system to activate when the innate immune system fails to subdue an infection. Cytokines direct the adaptive immune system to produce pathogen-specific antigens that quickly identify the pathogen so the immune system can destroy it.
  • Cytokine response is slow to avoid collateral damage to the body because if rapid immune response is there it will cause loads of cytokines leading to hyperinflammation, which can lead to shock and organ damage. The fine-tuned T-cell response can then attack the infection without causing excess harm to the body.

What is Cytokine Storm

Too many pathogens released at once

  • A cytokine storm may occur when too many pathogens enter the body at once, or if the body secretes the wrong type of cytokine early in the immune response, in which case the excessive cytokines can՚t accurately direct the immune system to clear out the pathogen. Because nearly every organ has cytokine receptors, almost every part of the body is susceptible to the negative effects of a cytokine storm.
  • A normal release of cytokines causes blood vessel walls to become leakier in order to promote healing of damaged tissue via inflammation, but too many cytokines may cause blood vessels to become overly porous and result in low blood pressure, leads to reduced oxygen in the blood, fluid build-up in the lungs, difficulty breathing.
  • Cytokine storms can also cause neurological issues. The brain is naturally protected from harmful chemicals thanks to the blood-brain barrier. But cytokines are much smaller than cells, so they can slip through the brain՚s protective membrane. Cytokine storms have been known to cause symptoms such as headache, migraine, decreased appetite, increased need for sleep and overwhelming fatigue

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