12 - CYTOKINE FAMILY

What are cytokines

Hormone-like glycoproteins (8–25 kDa) that act as cell signaling molecules

Which cells secrete cytokines

Lymphocytes, monocytes/macrophages, fibroblasts, and endothelial cells

What are the main functions of cytokines

Cell growth and activation, immune response, inflammation, and chemotaxis

What is pleiotropy in cytokines

One cytokine produces multiple different effects

What is redundancy in cytokines

Different cytokines perform the same function

What is synergy in cytokines

Cytokines enhance each other's effects

What is antagonism in cytokines

Cytokines oppose each other's effects

How do cytokines exert their effects

By binding to specific cell receptors and activating intracellular signaling pathways

What are the main effects after cytokine binding

Cell activation or inhibition and immune modulation

At what concentrations do cytokines act

Very low concentrations

What are the major cytokine families

Interferons, interleukins, tumor necrosis factors, colony-stimulating factors, migration inhibitory factor, and chemokines

What stimulates the production of interferons

Viral infections

Which cells produce interferons

Leukocytes, fibroblasts, and T-cells

What is the main function of interferons

Antiviral activity

What are the functions of IFN-α

Inhibits viral replication and activates macrophages

What are the functions of IFN-β

Inhibits viral growth and enhances immune response

What is the function of IFN-γ

Immunoregulation and activation of immune responses

What are interleukins

Cytokines that mediate communication between immune cells

Which cells mainly produce interleukins

Leukocytes (also fibroblasts and endothelial cells)

What are the functions of IL-1

Activates T and B cells, causes fever, induces inflammation, and stimulates prostaglandin production

What are the functions of IL-2

Stimulates T-cell growth, activates B cells, enhances cytotoxic response, and is used in cancer therapy

What is the function of IL-3

Stimulates hematopoiesis affecting granulocytes, macrophages, and lymphocytes

What are the functions of IL-4

Activates B cells, promotes IgG and IgE production, and is important in allergic reactions

What are the functions of IL-5

Stimulates eosinophils, promotes B-cell differentiation, and is important in parasitic infections

What are the functions of IL-6

Promotes plasma cell formation, induces acute-phase proteins, and causes fever

What is the function of IL-7

Stimulates T-cell growth and supports lymphocyte development

What are the functions of IL-8

Causes chemotaxis of neutrophils and promotes inflammation

What are the functions of IL-10

Anti-inflammatory and stimulates B-cell proliferation

What are the functions of IL-11

Stimulates B cells and promotes acute-phase protein production

What are the functions of IL-12

Activates T-helper cells and promotes cell-mediated immunity

What are the functions of IL-13 to IL-17

IL-13 stimulates B cells and inhibits macrophages, IL-14 enhances B-cell proliferation, IL-15 activates NK and T cells, IL-16 is chemotactic for CD4 cells, and IL-17 promotes inflammation by inducing IL-6 and IL-8

What is the main function of tumor necrosis factor

Cytotoxic to tumor cells and promotes inflammation

Which cells produce TNF

Macrophages, T-cells, B-cells, and fibroblasts

What are the functions of TNF-α

Promotes inflammation and activates macrophages

What are the functions of TNF-β

Activates cytotoxic cells and enhances immune response

What are colony-stimulating factors

Cytokines that stimulate bone marrow cell production and hematopoiesis

What is the function of M-CSF

Stimulates monocytes to differentiate into macrophages

What is the function of G-CSF

Stimulates proliferation and differentiation of granulocytes

What is the function of GM-CSF

Acts on granulocytes and macrophages and enhances phagocytosis and cytotoxicity

What is migration inhibitory factor

A cytokine produced by T-cells that inhibits macrophage migration and keeps them at infection sites

What are chemokines

A subgroup of cytokines responsible for cell migration and chemotaxis

What is the main function of chemokines

Attract leukocytes to infection sites

What are the main types of chemokines

CC chemokines and CXC chemokines

Which cells are targeted by CC chemokines

Monocytes and T cells

Which cells are targeted by CXC chemokines

Neutrophils

What determines chemokine function

Structural differences based on cysteine residues

What are chemokine receptors

CCR and CXCR

What are the roles of chemokines in the body

Infection, inflammation, and tissue repair

What is the clinical use of cytokines

Used in cancer therapy (e.g., IL-2) and infection control

What are the risks of excessive cytokine production

Shock, severe inflammation, and cytokine storm