Immunology: Innate and Adaptive Immunity

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Questions and Answers

The following cells are the main players in the innate defense system:

neutrophils (correct)

dendritic cells (correct)

natural killer cells (NK) (correct)

lymphocytes (BT)

phagocytes (correct)

Physiological role of the immune system is:

Defence against infections (correct)

Control of tissue regeneration and scaring

Defence against transplantation

Defence against tumours (correct)

Inducing of allergy (correct)

Immunity:

passive immunity protect neonatal

active immunity is induced in humans by infections (correct)

passive immunity is induced in humans by vaccination (correct)

active immunity is induced if antibodies from another already immune individuals are intravenously administrated to patients with agammaglobulinemia

passive immunity is induced if lymphocytes from another already immune individuals are intravenously administrated to humans with immunodeficiency

Functions of adaptive immunity are:

elimination of phagocytosed microbes by activation of macrophages, which are activated by cytokines secreted by helper T lymphocytes Signup and view all the answers

Immune response:

Antigen-presenting Cells (APCs) dendritic cells capture of antigen for initiation of lymphocytes T response Signup and view all the answers

Cytokines produced by T helpers by recognition of the microbial antigen presented by APCs:

kill the infected cells Signup and view all the answers

Immunological memory:

when memory cells encounter the same antigen that induced their development, the cells rapidly respond to initiate secondary immune response Signup and view all the answers

Peripheral lymphoid organs and tissues:

the major components of the cutaneous immune system present in dermis are: plasma cells, mast cells, macrophages, T lymphocyte CD4+ and dermal dendritic cells; in epidermis: keranocytes, epidermal Langerhans cells and intraepithelial lymphocyte CD8+ Signup and view all the answers

Complement system:

can be initiated by antibodies binding to microbes in alternative pathway Signup and view all the answers

Specificities of Toll-like receptors (TLR):

TLR-5 is specific for bacterial flagellin of Gram-positive bacteria Signup and view all the answers

Inflammation:

TLR engagement by bacterial molecules increase expression of proinflammatory cytokines Signup and view all the answers

Antiviral defence:

the RIG-like receptors (RLRs) are cytosolic proteins that sense viral RNA and induce production of antiviral type I interferon Signup and view all the answers

Precipitation is used:

in radial immunodiffusion to measure of the antigen titter Signup and view all the answers

Cases:

non-productive cough, fever, increased lymphocytes in blood make it possible to suspect interstitial viral pneumonia Signup and view all the answers

Cytokine:

IFN-gamma activates macrophages Signup and view all the answers

Study Notes

Innate Immune System

Main players: Dendritic cells, natural killer cells (NK), neutrophils, phagocytes
Innate response is faster than adaptive response to new microbes
Immunological tolerance is the unresponsiveness to self
Immune system functions include controlling tissue regeneration, defense against infections, transplants, and tumors
Antigen-presenting cells (APCs) capture antigens for lymphocyte T responses

Adaptive Immunity

Active immunity develops from infections
Passive immunity develops through vaccinations or transfer of antibodies from another immune individual
Memory cells survive long-term and rapidly respond to re-exposure to antigens

Cytokines and Immune Response

T helper cells produce cytokines that activate macrophages, kill infected cells, and activate inflammation processes
Cytokines activate B lymphocytes

Lymphocytes and Immune Response

Helper T lymphocytes are activated by antigen-presenting cells (APCs)
Plasma cells develop into effector B lymphocytes for antibody production
Lymphocytes are a type of cell of the adaptive immune system

Peripheral Lymphoid Organs and Tissues

Spleen is important for capturing and concentrating blood-borne antigens
Macrophages in the spleen destroy old red blood cells
Cutaneous immune system components include plasma cells, mast cells, macrophages, T lymphocytes (CD4+), and dermal dendritic cells in the dermis
Keratinocytes, epidermal Langerhans cells, and intraepithelial lymphocytes (CD8+) in the epidermis

Complement System

Complement system plays a role in defense through opsonization (C3b), phagocytosis, inflammation (C5a and C3a), and cell lysis (MAC formation): a cascade of biochemical reactions of proteins involved in innate immunity.
Complement activation can occur through antibodies or by mannose-binding lectin which is an innate activation pathway

Toll-like Receptors (TLRs)

TLRs recognize specific molecules from microbes
TLR engagement increases pro-inflammatory cytokines and adhesion molecules
Individual TLRs recognize particular structures such as bacterial molecules

Inflammation

TLR engagement increases pro-inflammatory cytokines and adhesion molecules
COX-1 and COX-2 are activated in arachidonic acid cycle for prostaglandin expression

Antiviral Defense

RIG-like receptors (RLRs) sense viral RNA and induce type I interferon production
RLRs recognize typical mammalian double-stranded RNA features
Cytosolic DNA sensors recognize double-stranded DNA and initiate type I interferon production and autophagy
Type I interferons stimulate by the STING pathway

Cytokines

Macrophages, T cells, etc. produce cytokines (e.g., TNF, IL-1, IL-6) to elicit responses.
Cytokines regulate inflammation, cell death, and other aspects of immunity

Other Concepts

Precipitation is a technique used in various immunological tests.
Cases (e.g., HAE, SLE) may involve malfunctions in the complement system, leading to diseases.
Specificities of TLRs relate to recognition of distinct microbial parts. Examples include gram-negative and gram-positive bacteria

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Description

Explore the key concepts of the innate and adaptive immune systems in this quiz. Learn about the roles of various immune cells, the differences between active and passive immunity, and the function of cytokines in immune responses. Test your knowledge on how the immune system defends against infections and maintains tolerance.