Immune System Cells: Monocytes, Macrophages, and NK Cells

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Questions and Answers

Which type of immune cells are responsible for inducing IFN-γ production and killing tumor cells?

NK cells (correct)

Dendritic cells

Macrophages

Monocytes

What type of signaling is involved in attracting and recruiting immune cells to the site of infection?

Paracrine signaling

Autocrine signaling

Chemokine signaling (correct)

Endocrine signaling

Which of the following is NOT a function of macrophages?

Antigen presentation

Antibody production (correct)

Phagocytosis

Cytokine production

What type of cells are involved in the engulfment of pathogens and larger particles?

Monocyte and macrophage Signup and view all the answers

Which cytokine is involved in activating macrophages and cell-mediated immunity?

IFN-γ Signup and view all the answers

What is the process by which immune cells migrate from the blood stream into infected tissues?

Transendothelial migration Signup and view all the answers

Which type of interferon is produced by lymphocytes and NK cells and activates macrophages?

IFN-γ Signup and view all the answers

Which of the following is a function of antigen presentation?

Presentation of antigens to T-cells Signup and view all the answers

What is the main function of the physical barriers in innate immunity?

To provide an immediate defense against infectious agents Signup and view all the answers

Which of the following is NOT a type of antimicrobial peptide found in secretions?

Interferons Signup and view all the answers

What is the primary function of the spleen in innate immunity?

To filter out pathogens from the bloodstream Signup and view all the answers

Which type of immune cell is primarily involved in phagocytosis?

Neutrophil Signup and view all the answers

What is the role of collectins in innate immunity?

To recognize and bind to polysaccharides on microorganisms Signup and view all the answers

Which of the following is NOT a function of mast cells?

To phagocytose pathogens Signup and view all the answers

What is the primary function of lymphatic vessels in innate immunity?

To connect tissues with lymph nodes Signup and view all the answers

Which of the following organs is responsible for T-cell maturation?

Thymus Signup and view all the answers

What is the function of proteolytic enzymes in killing and degradation?

To break down proteins at low pH Signup and view all the answers

Which type of antigens are presented by MHC class I?

Endogenous antigens from viruses and mycobacteria Signup and view all the answers

What is the result of antigen presentation by MHC class I?

Cytotoxicity and killing of infected cells Signup and view all the answers

Which cells are responsible for antigen presentation via MHC class II?

Macrophages, dendritic cells, and B cells Signup and view all the answers

What is the role of defensins in killing and degradation?

To form a protective barrier against pathogens Signup and view all the answers

What is the function of respiratory burst in killing and degradation?

To generate oxygen radicals Signup and view all the answers

Which type of immunity is primarily involved in the response to intracellular pathogens?

Cell-mediated immunity Signup and view all the answers

What is the role of NO in killing and degradation?

To inhibit viral replication Signup and view all the answers

Study Notes

Monocyte and Macrophage

Engulf pathogens and larger particles, including dead cells and damaged tissues
Present antigens on MHC class I or II

NK Cells

Induce IFN-γ production, activating macrophages and cell-mediated immunity
Kill tumor cells, viral-infected cells, and protozoan-infected cells using granzyme and perforin

Inflammatory Response

Mediated by cytokines, chemokines, and innate immune cells
Involves phagocytosis and inflammatory response

Cytokines

Paracrine: released by producer and acts on neighboring cells
Autocrine: produced, released, and acts on the producer
Endocrine: released by producer into the circulation and acts on a distant cell

Interferons

IFN-α and IFN-β: produced by macrophages, fibroblasts, endothelial, and epithelial cells; activated by viral dsRNA; have antiviral effects
IFN-γ: produced by lymphocytes and NK cells; activates macrophages

Migration of Cells from Blood Stream into Infected Tissues

Rolling: a process involving IL-1, TNF-α, and vasodilation
Involves activation of innate immune cells, such as PMN cells, and the release of chemokines

Innate Immunity and the Inflammatory Response

Innate immunity: pre-existing defense against infection, mounts an immediate response to infectious agents
Activation of innate immunity leads to an inflammatory response

Components of Innate Immunity

Physical barriers: skin, mucous membranes, and epithelial cells
Chemical and biochemical barriers: lysozyme, fatty acids, HCL, and lactic acid

Antimicrobial Peptides in Secretions

Defensins: found in mucosal and skin secretions
Cathelicidins: found in mucosal secretions
Collectins: bind to polysaccharides on microbes

Lymphoid Organs

Primary: bone marrow (B cell maturation) and thymus (T cell maturation)
Secondary: lymph nodes, spleen, and MALT (Payer’s patch)

Lymphatic Vessels and Spleen

Lymphatic vessels connect tissues with lymph nodes and contain lymphocytes and tissue dendritic cells
Spleen deals with antigens shed into the bloodstream and is not connected to lymphatic vessels

Innate Immune Cells

Mast cells: involved in hypersensitivity and release histamine, heparin, and proteolytic enzymes
Basophils: involved in hypersensitivity and release histamine, heparin, and proteolytic enzymes
Eosinophils: involved in hypersensitivity and parasitic infection, and release toxic agents
Neutrophils: phagocytose small pathogens and release oxygen radicals

Killing and Degradation

Lysosomal dependent: involves chlorine products, defensins, and proteolytic enzymes
Non-lysosomal dependent: involves respiratory burst, oxygen radicals, and NO (inhibits viral replication)

MHC Class I and II

MHC class I: presents endogenous peptides, involved in antigen presentation, and leads to cytotoxicity
MHC class II: presents extracellular antigens, found on antigen-presenting cells, and signals the activation of other immune cells and their inflammatory responses

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Description

Quiz about the functions of monocytes, macrophages, and NK cells in the immune system, including antigen presentation, pathogen elimination, and inflammatory response.