6.1 Cytokines, Cytokine Receptors and Chemokines
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Questions and Answers

Which type of effect is described when cytokines bind to receptors on the cell that produced them?

  • Autocrine effect (correct)
  • Endocrine effect
  • Paracrine effect
  • Cytokine effect

In the context of cytokines, what is a paracrine effect?

  • Combination with PAMPs
  • Binding to receptors on the cell that produced them
  • Binding only to receptors on nearby cells (correct)
  • Effect on distant locations

Which molecules act through toll-like receptors and trigger cytokine release?

  • Antibodies
  • Receptors
  • Cytokines
  • PAMPs (correct)

What are the most important pathways that trigger cytokine release?

<p>Combination of antigens with T and B cell receptors (C)</p> Signup and view all the answers

Which type of effect do cytokines have when they spread throughout the body and affect target cells in distant locations?

<p>Endocrine effect (A)</p> Signup and view all the answers

What distinguishes cytokines from hormones in terms of their effects?

<p>Cytokines have autocrine or paracrine effects, while hormones have endocrine effects. (D)</p> Signup and view all the answers

Which term describes the ability of a single cytokine to act on many different target cell types?

<p>Pleiotropy (B)</p> Signup and view all the answers

In cytokine functions, what does the term 'redundancy' refer to?

<p>Multiple cytokines acting on a single target cell (A)</p> Signup and view all the answers

What is the process called when some cytokines work best when paired with other cytokines?

<p>Synergy (A)</p> Signup and view all the answers

Which statement best describes the impact of cytokines binding to receptors on target cells?

<p>They affect cell behavior. (B)</p> Signup and view all the answers

How do cytokines differ from conventional hormones?

<p>Cytokines affect multiple cell types, while hormones affect a single target cell type. (B)</p> Signup and view all the answers

Which type of transmission involves a mediator molecule diffusing through the extracellular fluid to the receiving cell?

<p>Volume transmission (B)</p> Signup and view all the answers

What are the most important molecular mediators known as cytokines?

<p>Leukins, monokins, prostaglandins, and interferons (C)</p> Signup and view all the answers

Which of the following is NOT a cytokine?

<p>Prostaglandin (C)</p> Signup and view all the answers

How do cells of the immune system communicate among each other using cytokines?

<p>By releasing multiple different proteins to control immune responses (A)</p> Signup and view all the answers

What is the main difference between volume transmission and network transmission of intercellular signals?

<p>Volume transmission involves mediator molecules diffusing, while network transmission involves direct cell contact. (B)</p> Signup and view all the answers

Which of the following cytokines is a chemokine that acts on the brain to cause a fever?

<p>CCL3 (A)</p> Signup and view all the answers

Which of the following is NOT a characteristic of cytokines?

<p>Long-lived proteins (C)</p> Signup and view all the answers

Which of the following is NOT a type of interferon?

<p>IFN-δ (D)</p> Signup and view all the answers

Which of the following cytokines is primarily produced by macrophages and T cells?

<p>TNFα (A)</p> Signup and view all the answers

Which of the following is NOT true about interleukins?

<p>They are primarily involved in antiviral activity (D)</p> Signup and view all the answers

Which of the following cytokines is primarily involved in the maintenance of pregnancy?

<p>IFN-α (B)</p> Signup and view all the answers

Which cytokine plays a critical role in inflammation and is also involved in fever, hematopoiesis, appetite control and acquired immunity?

<p>IL-1 (B)</p> Signup and view all the answers

Which cytokine is produced not only by activated macrophages but also by T and B cells, mast cells, vascular endothelial cells, fibroblasts, and keratinocytes?

<p>IL-6 (A)</p> Signup and view all the answers

Which cytokine is produced by TNF-α and IL-12 synergistically and promotes IFN-γ production?

<p>IFN-γ (B)</p> Signup and view all the answers

Which cytokine is produced by activated Th2 cells, mast cells and eosinophils and controls eosinophil production?

<p>IL-5 (D)</p> Signup and view all the answers

Which cytokine is an immunosuppressive and anti-inflammatory cytokine that regulates inflammation, as well as T cell, NK cell, and macrophage function?

<p>IL-10 (C)</p> Signup and view all the answers

Which cytokine is produced by T cells, B cells, NK cells, and mast cells and acts on B cells, T cells, macrophages, and mast cells, stimulating the growth and differentiation of B cells?

<p>IL-4 (D)</p> Signup and view all the answers

Which cytokine is produced by T cells, B cells, NK cells, and mast cells and acts on B cells, T cells, macrophages, and mast cells, stimulating the growth and differentiation of B cells?

<p>IL-4 (C)</p> Signup and view all the answers

Which cytokine is produced by Th1 cells and is required for the final maturation of B cells into plasma cells?

<p>IL-6 (B)</p> Signup and view all the answers

Which cytokine is produced by Th2 cells and is a potent stimulator of innate immunity?

<p>IFN-γ (D)</p> Signup and view all the answers

Which cytokine is produced by Th2 cells and is a stem cell growth factor produced only by Th2 cells?

<p>IL-9 (B)</p> Signup and view all the answers

What is one of the distinguishing characteristics of cytokines?

<p>Can have overlapping biological functions (D)</p> Signup and view all the answers

Which statement best describes the nomenclature of interleukins?

<p>Heterogeneous mixture with little in common except their name (B)</p> Signup and view all the answers

Which type of interferons primarily have antiviral activity?

<p>Type I interferons (C)</p> Signup and view all the answers

What do type III interferons, such as IFN-λ, primarily possess?

<p>Immunoregulatory role (C)</p> Signup and view all the answers

Which cells secrete TNFs according to the text?

<p>Macrophages and T cells (D)</p> Signup and view all the answers

What is the primary function of TNF-α?

<p>Immune regulation (D)</p> Signup and view all the answers

Which of the following cytokines is NOT a member of the TNF superfamily?

<p>CXCL8 (B)</p> Signup and view all the answers

What is the function of chemokines in the immune system?

<p>Leukocyte chemotaxis (B)</p> Signup and view all the answers

Which type of cytokines are secreted by monocytes-macrophages?

<p>Monokines (A)</p> Signup and view all the answers

What is the primary function of interleukins in the immune system?

<p>Regulating interactions between lymphocytes and leucocytes (D)</p> Signup and view all the answers

What is the primary difference between volume transmission and network transmission of intercellular signals?

<p>Volume transmission involves diffusion of a mediator molecule, while network transmission involves direct contact between two cells. (A)</p> Signup and view all the answers

How do cytokines differ from conventional hormones regarding their target cell types?

<p>Cytokines can affect many different cell types, while conventional hormones tend to affect a single target cell type. (C)</p> Signup and view all the answers

Which type of cells secrete multiple cytokines simultaneously?

<p>Macrophages (D)</p> Signup and view all the answers

What sets cytokines apart from conventional hormones in their secretion by immune system cells?

<p>Immune system cells secrete a single cytokine at a time, unlike conventional hormones. (D)</p> Signup and view all the answers

Which of the following is NOT a type of cytokine mentioned as an important molecular mediator?

<p>Leptins (C)</p> Signup and view all the answers

What characterizes the direct contact method of network transmission among cells?

<p>Two cells use complementary receptors to transmit signals to each other. (D)</p> Signup and view all the answers

What is the term that describes the ability of many different cytokines to act on a single target cell?

<p>Redundancy (B)</p> Signup and view all the answers

Which of the following is NOT a characteristic of cytokines?

<p>Endocrine effects (A)</p> Signup and view all the answers

What term describes the ability of a single cytokine to act on many different target cell types, inducing different responses in each one?

<p>Pleiotropy (B)</p> Signup and view all the answers

What is the process called when some cytokines work best when paired with other cytokines?

<p>Synergy (A)</p> Signup and view all the answers

Which cytokine is produced by Th2 cells and is a potent stimulator of innate immunity?

<p>IL-4 (B)</p> Signup and view all the answers

Which of the following is NOT a pathway that triggers cytokine release?

<p>The combination of antigens with Fc receptors on T and B cells (B)</p> Signup and view all the answers

Which of the following is NOT a type of cytokine effect?

<p>Intracrine effect (D)</p> Signup and view all the answers

Which of the following does NOT act through toll-like receptors and trigger cytokine release?

<p>Toll-like receptors (TLRs) (C)</p> Signup and view all the answers

Which of the following is NOT a function of cytokines?

<p>They bind to receptors on the nucleus of the cell (B)</p> Signup and view all the answers

Which of the following is NOT a type of cell that produces cytokines?

<p>Nerve cells (C)</p> Signup and view all the answers

Flashcards

What are cytokines?

Molecular messengers that regulate immune responses by communicating between cells.

How do cytokines communicate?

Cytokines use two main methods to communicate: volume transmission, where signals spread widely, and network transmission, where signals are sent between specific cells.

What are some actions of cytokines?

Cytokines can stimulate cell division, differentiation, or protein synthesis.

Can cytokines have inhibitory effects?

Cytokines can also suppress cell division, differentiation, or protein synthesis.

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What is pleiotropy in cytokine function?

A single cytokine can affect multiple cell types, each with a unique response.

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What is redundancy in cytokine function?

Multiple cytokines can work together to produce a single effect.

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Can cytokines work together?

Cytokines can work in synergy with other cytokines to achieve a greater effect.

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Is there a systematic way to name cytokines?

The naming of cytokines doesn't follow a strict pattern.

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How were cytokines originally named?

Cytokines were initially named based on their origin cell or the method used to identify them.

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What are interleukins?

Interleukins are cytokines that communicate specifically between lymphocytes and other leukocytes.

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How many different interleukins are there?

There exist 39 different interleukins, each with its unique function.

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What are interferons?

Interferons are cytokines produced in response to viral infections or immune stimulation and have antiviral activity.

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How long do cytokines last?

Cytokines are short-lived proteins, quickly breaking down.

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What are the structural features of cytokines?

Cytokines have diverse structures and specific receptors.

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Where do cytokines act?

Cytokines can act locally in a specific area or systemically throughout the body.

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What is pleiotropy in regards to cytokines?

Cytokines can affect many different cell types.

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What is redundancy in regards to cytokines?

Cytokines can have overlapping functions, with different cytokines potentially performing similar tasks.

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How are cytokines regulated?

Cytokine production is tightly controlled and excessive levels can be harmful.

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What cytokines do macrophages produce?

Macrophages produce IL-1, IL-6, IL-12, IL-18, and TNF-α.

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What is the function of IL-1?

IL-1 plays a critical role in inflammation, fever, blood cell production, appetite control, and acquired immunity.

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What is the function of IL-6?

IL-6 is produced by activated macrophages, T cells, B cells, mast cells, and various other cell types.

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What is the function of IL-12?

IL-12 promotes the activity of Th1 cells, which are important for cell-mediated immunity.

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What is the function of IL-18?

IL-18 acts on Th1 cells to promote the production of IFN-γ, IFN-α, IL-1, and other chemokines.

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What is the function of TNF-α?

TNF-α is a potent pro-inflammatory molecule involved in inflammation, tissue repair, and cell death.

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What cytokines do Th1 cells produce?

Th1 cells produce IL-2, TNF-γ, and IFN-γ.

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What is the function of IL-2?

IL-2 activates helper and cytotoxic T cells, as well as natural killer (NK) cells.

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What is the function of IFN-γ?

IFN-γ stimulates B cells to produce IgG antibodies and enhances T cell expression of MHC class I molecules.

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What cytokines do Th2 cells produce?

Th2 cells produce IL-4, IL-5, IL-9, IL-10, and IL-13.

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What is the function of IL-4?

IL-4 acts on B cells, T cells, macrophages, and mast cells, stimulating B cell growth and differentiation.

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What is the function of IL-5?

IL-5 controls eosinophil production and stimulates their growth and differentiation.

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What is the function of IL-10?

IL-10 is an immunosuppressive and anti-inflammatory cytokine that regulates inflammation and immune cell function.

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What is the function of IL-13?

IL-13 has effects similar to IL-4 on B cells and macrophages, stimulating their proliferation and antibody secretion.

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Study Notes

Cytokines Introduction

  • Cytokines are molecular mediators that control immune responses by communicating among cells
  • The immune system forms complex networks involving many different cell types, each sending and receiving multiple messages from many different sources
  • Intercellular signals are transmitted in two general ways: volume transmission and network transmission

Cytokine Functions

  • Cytokines affect cell behavior, inducing cell division, differentiation, or stimulating the production of new proteins
  • Cytokines can inhibit cell division, differentiation, or new protein synthesis
  • Most cytokines act on many different target cell types, inducing different responses in each one (pleiotropy)
  • Many different cytokines may act on a single target, a feature known as redundancy
  • Cytokines can work in synergy with other cytokines to produce an effect

Cytokine Nomenclature

  • The nomenclature and classification of cytokines is not based on any systematic relationship among these proteins
  • Cytokines were originally named after their cell of origin or the bioassay used to identify them
  • Interleukins are cytokines that mediate signaling between lymphocytes and other leukocytes
  • There are 39 different numbered interleukins, each with different functions
  • Interferons are cytokines produced in response to virus infection or immune stimulation and have antiviral activity

Properties of Cytokines

  • Cytokines are short-lived proteins
  • Cytokines have highly diverse structures and receptors
  • Cytokines can act locally and/or systemically
  • Cytokines are pleiotropic, affecting many different cells
  • Cytokines are redundant, exhibiting biologically overlapping functions
  • Cytokines are carefully regulated and can be toxic in high doses

Cytokines Produced by Macrophages and Dendritic Cells

  • Macrophages produce IL-1, IL-6, IL-12, IL-18, and TNF-α
  • IL-1 plays a critical role in inflammation, fever, hematopoiesis, appetite control, and acquired immunity
  • IL-6 is produced by activated macrophages, T cells, B cells, mast cells, vascular endothelial cells, fibroblasts, and keratinocytes
  • IL-12 promotes Th1 cell activity and enhances T and NK cell proliferation and cytotoxicity
  • IL-18 acts on Th1 cells to promote the production of IFN-γ, IFN-α, IL-1, and several chemokines
  • TNF-α is a potent pro-inflammatory molecule that enhances the expression of adhesive molecules, promotes fibroblast proliferation and collagen production

Cytokines Produced by T Cells

  • Th1 cells produce IL-2, TNF-γ, and IFN-γ
  • IL-2 activates helper and cytotoxic T cells and NK cells
  • IFN-γ stimulates B cell production of IgG and enhances T cell production of MHC class I molecules
  • Th2 cells produce IL-4, IL-5, IL-9, IL-10, and IL-13
  • IL-4 acts on B cells, T cells, macrophages, and mast cells, stimulating the growth and differentiation of B cells
  • IL-5 controls eosinophil production and stimulates the growth and differentiation of eosinophils
  • IL-10 is an immunosuppressive and anti-inflammatory cytokine that regulates inflammation and T cell, NK cell, and macrophage function
  • IL-13 has similar effects to IL-4 on B cells and macrophages, stimulating their proliferation and increasing immunoglobulin secretion.

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Learn about the complex networks involved in immunology where different cell types communicate through intercellular signals. Explore the two general ways of signal transmission: volume transmission and contact-dependent signaling.

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