Cytokines in Immune Response

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Questions and Answers

What is the primary function of cytokines in the body?

To filter waste from the blood

To maintain blood pressure

To aid in the digestion of food

To regulate immune response and inflammation (correct)

Which type of cytokine is released by virus-infected cells and involved in immunoregulation?

Interferons (correct)

Chemokines

Colony Stimulating Factors

Interleukins

What is the term for cytokines that have a similar effect on the target cell?

Antagonistic effect

Synergistic effect

Redundant effect (correct)

Pleiotropic effect

What is the characteristic of cytokines in which they can act on different cells?

Pleiotropic Signup and view all the answers

How are cytokines typically synthesized?

Through gene transcription Signup and view all the answers

What is the term for cytokines that increase chemotaxis?

Chemokines Signup and view all the answers

How do cytokines typically interact with their target cells?

Through ligand-receptor binding Signup and view all the answers

What is the term for the effect of cytokines on cells in their immediate surroundings?

Paracrine effect Signup and view all the answers

What is the primary function of Interleukin-3?

Promotes proliferation of pluripotent stem cells in the bone marrow Signup and view all the answers

Which of the following cytokines is not formed by the Th2 subset of helper T-lymphocytes?

IL-6 Signup and view all the answers

What is the primary function of Interleukin-8?

Chemoattractant for leukocytes to the site of inflammation Signup and view all the answers

What is the main stimulus that initiates the synthesis and release of TNF?

Lipopolysaccharides produced by Gram-negative bacteria Signup and view all the answers

What is the role of Interleukin-4?

Anti-inflammatory cytokine that induces conversion to TH2 Signup and view all the answers

Which of the following is synthesized by cells in the bone marrow stroma?

IL-3 Signup and view all the answers

Which of the following is a T cell growth factor?

Interleukin-2 Signup and view all the answers

What is the effect of TNF-α on vascular permeability?

It increases Signup and view all the answers

What is Interleukin-6 involved in?

Both A and B Signup and view all the answers

Which type of cells release TNF-β?

T-lymphocytes Signup and view all the answers

What is the effect of TNF-α on fever?

It causes fever by acting on the hypothalamus Signup and view all the answers

What is the effect of Interleukin-1 on T and B-lymphocytes?

It shows a mitogenic effect Signup and view all the answers

Which of the following is a proinflammatory cytokine?

TNF-α Signup and view all the answers

What is the primary function of cytokines in adaptive immunity?

Induction of proliferation of T and B lymphocytes in response to a specific antigen Signup and view all the answers

What is the effect of TNF-α on the synthesis of acute phase reactants?

It increases Signup and view all the answers

Which of the following cytokines is NOT involved in natural immunity?

IL-2 Signup and view all the answers

What is the effect of TNF on cancer cells?

Induction of apoptosis Signup and view all the answers

Which of the following cytokines is a stimulant of hematopoiesis?

IL-7 Signup and view all the answers

What is the primary source of cytokines in natural immunity?

Cells of the monocyte/macrophage series Signup and view all the answers

What is the role of Th1 lymphocytes in adaptive immunity?

Induction of cellular immunity and proinflammation Signup and view all the answers

Which of the following is a granuloma-forming cytokine?

IL-12 Signup and view all the answers

What is the effect of TNF on acute inflammation?

Stimulation of acute inflammation Signup and view all the answers

What is the effect of IL-10 on IFN-γ production in TH1?

Inhibition Signup and view all the answers

Which cytokine is responsible for the synergistic effect with IL-2?

IL-12 Signup and view all the answers

What is the effect of IL-13 on airway response to allergens in asthma?

Excessive Signup and view all the answers

What is the effect of IL-18 on sepsis, especially in gram-positive infections?

Elevated Signup and view all the answers

What is the main function of Type 1 Interferons?

Antiviral effect Signup and view all the answers

What is the effect of IFN-α on macrophages?

Activation Signup and view all the answers

What is the effect of IFN-β on NK cells?

Activation Signup and view all the answers

What is the effect of IFN-γ on TH1 lymphocyte and NK cells?

Formation Signup and view all the answers

Which cytokine promotes the proliferation of connective tissue cells and is important in wound healing?

PDGF Signup and view all the answers

Which growth factor induces angiogenesis and is released from connective tissue and keratinocytes?

FGF Signup and view all the answers

Which cytokine is synthesized by platelets, macrophages, endothelial cells, and keratinocytes?

PDGF Signup and view all the answers

What is the effect of TGF-β on macrophage activity?

Decreases macrophage activity Signup and view all the answers

Which growth factor is responsible for growth and development in fetal life?

IGF-2 Signup and view all the answers

What is the function of CSFs in the body?

Activate leukocyte colonies Signup and view all the answers

Which growth factor is involved in the initiation of collagen synthesis and the healing process?

TGF-β Signup and view all the answers

What is the effect of PDGF on fibroblast and smooth muscle proliferation?

Increases fibroblast and smooth muscle proliferation Signup and view all the answers

Which cytokine is involved in the differentiation and development of erythroid precursor cells?

Erythropoietin Signup and view all the answers

What is the effect of EGF on keratinocytes and fibroblasts?

Increases migration and proliferation Signup and view all the answers

Study Notes

Definition of Cytokines

Low molecular weight, soluble protein or glycoprotein molecules that play a role in regulating immune response, inflammation, and hematopoiesis, serving as chemical messengers.
Also involved in mitosis, cell differentiation, apoptosis, and oncogenesis.

Classification of Cytokines

Interleukins: Released by leukocytes and affecting other leukocytes.
Interferons: Released from virus-infected cells and involved in immunoregulation.
Chemokines: Increase chemotaxis.
Colony Stimulating Factors: Ensure differentiation and proliferation of stem cells.

Common Features of Cytokines

Produced primarily by T-lymphocytes and monocytes/macrophages.
Pleiotropic molecules (can act on different cells).
May have redundant effects (similar effects on target cells).
Can be multifunctional and perform the same function as other cytokines.
Not stored, synthesized as a result of gene transcription.
Target cells have specific receptors.
Effects can be additive, synergistic, or antagonistic to each other.

Mechanisms of Impact

Cytokines act by binding to receptors on the cell membrane.
Intracellular effects occur through two ways:
- Tyrosine kinase activation (Janus kinase or JAK).
- Phospholipase C activation.

Classification of Cytokines by Function

Cytokines responsible for natural (nonspecific) immunity: TNF, IL-1, IL-6, IL-10, IL-12, interferons.
Cytokines responsible for specific (adaptive) immunity: IL-2, IL-4, IL-5, interferons.
Cytokines that stimulate hematopoiesis: CSFs, IL-3, IL-7.

Cytokines in Natural Immunity

Involved in early inflammatory response.
Primarily synthesized by cells of the monocyte/macrophage series.
Warnings for synthesis: bacterial endotoxins, teichoic acid, peptidoglycan monomers.

Cytokines in Adaptive Immunity

Formed by T-lymphocytes recognizing a particular antigen.
Induce proliferation of T and B lymphocytes in response to antigen recognition.
Examples: IL-2, IL-4, IL-5, IFN- γ.

Stimulants of Hematopoiesis

Produced by bone marrow stroma cells and leukocytes.
Exert growth and differentiation effects on leukocyte precursors.
Examples: stem factor, IL-3, IL-7, IL-9, GM-CSF.

Classification of Cytokines by Function

Proinflammatory cytokines: TNF-α, β, IL-1, IL-6, IL-8, IL-12, IFN-γ.
Anti-inflammatory cytokines: TGF-β, IL-4, IL-10, IL-13.
Granuloma-forming cytokines: IL-2, IL-12, IFN-γ, TNF.
Cytokines that stimulate Natural Killer cells: IL-2, IL-12, IL-15, IFN-γ.

Definition of Cytokines

Low molecular weight, soluble proteins or glycoprotein molecules
Play a role in regulating immune response, inflammation, and hematopoiesis
Serve as chemical messengers
Involved in mitosis, cell differentiation, apoptosis, and oncogenesis

Types of Cytokines

Interleukins: released by leukocytes, affect other leukocytes
Interferons: released from virus-infected cells, involved in immunoregulation
Chemokines: increase chemotaxis
Colony Stimulating Factors (CSFs): ensure differentiation and proliferation of stem cells

Common Features of Cytokines

Produced primarily by T-lymphocytes and monocytes/macrophages
Pleiotropic molecules (act on different cells)
Redundant effect: multiple cytokines have a similar effect on target cells
Multifunctional: different cytokines can perform the same function
Not stored, synthesized as a result of gene transcription in a short time
Target cells have specific receptors
Effects can be additive, synergistic, or antagonistic to each other

Mechanisms of Impact

Act by binding to receptors on the cell membrane
Intracellular effects occur through two ways: tyrosine kinase activation and phospholipase C activation

Classification of Cytokines

Cytokines responsible for natural (non-specific) immunity: TNF, IL-1, IL-6, IL-10, IL-12, interferons
Cytokines responsible for specific (adaptive) immunity: IL-2, IL-4, IL-5, interferons
Cytokines that stimulate hematopoiesis: CSFs, IL-3, IL-7

Cytokines in Natural Immunity

Involved in early inflammatory response
Primarily synthesized by cells of the monocyte/macrophage series
Warnings for their synthesis: bacterial endotoxins (LPS, teichoic acid, peptidoglycan monomers)

Cytokines in Adaptive Immunity

Formed by T-lymphocytes that recognize a particular antigen
Induce proliferation of T and B lymphocytes in response to recognition of a specific antigen
Examples: IL-2, IL-4, IL-5, IFN-γ
Th1 lymphocytes induce cellular immunity and proinflammation, Th2 lymphocytes induce humoral immunity and anti-inflammatory mechanisms

Stimulants of Hematopoiesis

Produced by bone marrow stroma cells and leukocytes
Exert growth and differentiation effects on leukocyte precursors
Examples: stem factor, IL-3, IL-7, IL-9, GM-CSF

Classification of Cytokines based on Function

Proinflammatory cytokines: TNF-α, β, IL-1, IL-6, IL-8, IL-12, IFN-γ
Anti-inflammatory cytokines: TGF-β, IL-4, IL-10, IL-13
Granuloma-forming cytokines: IL-2, IL-12, IFN-γ, TNF
Cytokines that stimulate Killer Natural: IL-2, IL-12, IL-15, IFN-γ

TNF (Tumor Necrosis Factor)

Polypeptide cytokine with roles in innate immunity, cell regulation, cell differentiation, and apoptosis
Primary mediator of acute inflammation, along with IL-1 and 6
T lymphocyte proliferation, helper and cytotoxic T lymphocyte activation

IL-3, IL-7 (Cytokines Stimulating Hematopoiesis)

IL-3: promotes proliferation of pluripotent stem cells in the bone marrow
IL-7: induces proliferation and differentiation of immature T and B lymphocytes in the bone marrow

IL-4, IL-5

IL-4: anti-inflammatory cytokine, induces conversion to TH2, B lymphocyte proliferation factor, IgG1, IgE production
IL-5: growth factor for eosinophils, B lymphocyte plasmocyte differentiation factor, IgA production

IL-6

Synthesized by mononuclear cells, lymphocytes, fibroblasts
Primer stimulating the synthesis of acute phase reactants in the liver cytokine
B lymphocyte differentiation, acute phase protein synthesis, and adhesion
Both anti and pro-inflammatory cytokine, reduction of TNF-α and IL-1 activity

Chemokines (IL-8, MCP, MIP)

Chemotaxis and migration of leukocytes to the site of inflammation
Synthesized by leukocytes, epithelial and endothelial cells, and fibroblasts

IL-10, IL-12, IL-13

IL-10: anti-inflammatory cytokine, inhibition of IFN-γ production in TH1, inhibition of MHC class II production in macrophage
IL-12: proinflammatory cytokine, stimulation of TH1 lymphocyte transformation, synergistic effect with IL-2
IL-13: anti-inflammatory cytokine, excessive airway response to allergens in asthma

IL-15, IL-18

IL-15: increases neutrophil phagocytosis
IL-18: elevated in sepsis, especially in gram-positive infections

Interferons

Type 1 Interferons: released from virus-infected cells, antiviral, regulate the activity of the immune system
Type 2 Interferons: only IFN-γ, immunomodulatory effect

Growth Factors

PDGF (Platelet Derived Growth Factor)
FGF (Fibroblast Growth Factor)
EGF (Epidermal Growth Factor)
Erythropoietin
IGF (Insulin-like Growth Factor)
VEGF (Vascular Endothelial Growth Factor)

CSF (Colony Stimulating Factors)

G-CSF: Granulocytes-CSF
M-CSF: Monocytes-CSF
GM-CSF: effective against granulocytes and monocytes
Synthesized by lymphocytes and macrophages
Activate leukocyte colonies, increase adhesion, cytotoxicity, and phagocytosis ability of leukocytes

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Description

Learn about cytokines, low molecular weight protein molecules that regulate immune response, inflammation, and hematopoiesis. Discover their roles in cell differentiation, apoptosis, and oncogenesis.