Adaptive immunity Flashcards

Vocabulary flashcards based on lecture notes on adaptive immunity, T-lymphocytes, MHC, and antibody structure.

Adaptive Immunity

Immunity involving antigen-specific T and B lymphocytes that develop immunological memory.

T-lymphocytes

Lymphocytes that include Helper T cells, Regulatory T cells, and Cytotoxic T cells.

B-lymphocytes

Lymphocytes that produce antibodies and develop immunological memory.

Helper T cells

T cells that help B cells produce antibody, activate macrophages, and activate cytotoxic T cells.

Regulatory T cells

T cells that suppress excessive immune responses.

Cytotoxic T cells

T cells that kill infected cells.

Alpha-beta T cells

The main type of T cells encompassing Helper, Regulatory, and Cytotoxic T cells.

Gamma-delta T cells

T cells that directly recognise Ag or CD1-presented lipids and kill infected/stressed cells.

Apoptosis

Programmed cell death induced by cytotoxic T cells in infected cells, using Fas/FasL and Granzyme/perforin.

TCR (T-cell receptor)

Receptor on T cells that recognises antigen that has been processed into peptides.

MHC (Major Histocompatibility Complex)

Molecules that present processed antigens to T cells.

Endogenous Pathway

Processing pathway that produces peptides 8-10 amino acids long for presentation by MHC class I.

Exogenous Pathway

Processing pathway that produces peptides ~15 amino acids long for presentation by MHC class II.

MHC Class I

Found on all nucleated cells, specialized for alerting cytotoxic T-cells to intracellular infection.

MHC Class II

Found on 'professional antigen-presenting cells' (APCs), specialized for activating helper T-cells.

APC (Antigen-Presenting Cell)

Cells such as dendritic cells, macrophages, and B-cells that present antigens to T cells.

HLA (Human Leukocyte Antigen)

Human MHC Class I (HLA-A, -B, -C) and Class II (HLA-DP, -DQ, -DR) molecules.

Polymorphism (MHC)

The high degree of variability in MHC genes within a population.

Codominant Expression (MHC)

The expression of both alleles for MHC genes in an individual.

Primary Lymphoid Organs

Organs where lymphocytes develop and mature (Thymus and Bone Marrow).

Secondary Lymphoid Organs

Organs where immune responses are initiated (Lymph node, Spleen, MALT).

Thymus

Primary lymphoid organ for T-cell development and education.

Bone Marrow

Primary lymphoid organ where B-cells develop and mature.

Lymph Node

Secondary lymphoid organ that filters lymph and initiates immune responses to antigens in tissues.

Spleen

Secondary lymphoid organ that filters blood and initiates immune responses to antigens in the blood.

MALT (Mucosa-Associated Lymphoid Tissue)

Secondary lymphoid tissue that initiates immune responses to antigens at mucosal surfaces.

Positive Selection (T-cells)

Survival of T-cells that can recognize self MHC.

Negative Selection (T-cells)

Elimination of T-cells with high affinity for self MHC or self MHC + self peptides.

HEV (High Endothelial Venule)

Specialized venules in lymph nodes through which lymphocytes enter from the blood.

Dendritic Cells

Antigen-presenting cells that carry antigen to the lymph nodes to activate T cells.

Peyer's Patches

Lymphoid structures in the gut where immune responses are induced.

Germinal Center

Area within secondary lymphoid tissues where B cells proliferate, undergo somatic hypermutation, and class switch.

Follicular Dendritic Cells

Cells in the germinal center that display antigens to B cells.

PAMPs (Pathogen-Associated Molecular Patterns)

Molecules associated with pathogens that are recognized by Pattern Recognition Receptors (PRR).

DAMPs (Damage-Associated Molecular Patterns)

Molecules released from damaged cells that are recognized by Pattern Recognition Receptors (PRR).

Antibody (BCR)

Molecule on B cells that recognizes antigen.

V-D-J Recombination

The process by which immunoglobulin genes are rearranged to create diverse antibody specificities.

RAG-1 and RAG-2

Recombination-activating genes that encode recombinase enzymes for V-D-J recombination.

Class Switching

The process by which a B cell changes the class of antibody it produces.

IgM

First antibody class produced in an immune response; activates complement and is a powerful agglutinin.

IgG

Most abundant antibody in the blood; enhances phagocytosis and can cross the placenta.