T Cell Development & B Cell and Antibody Immunity

These flashcards summarize key terms and definitions related to T cell development and B cell and antibody immunity, drawn from the lecture notes.

Somatic recombination

An essential process for the generation of immunoglobulins and T-cell receptors, requiring V(D)J recombinase.

Omenn syndrome

An immunodeficiency caused by mutations in RAG1 or RAG2, leading to a rapidly fatal condition treatable only by bone marrow transplantation.

Immunoglobulin (Ig)

A type of antibody used by the immune system to identify and neutralize pathogens.

B cell receptor (BCR)

The surface immunoglobulin of B cells that binds antigens to initiate the immune response.

T cell receptor (TCR)

A molecule on the surface of T cells that recognizes and binds to antigens presented by MHC molecules.

MHC restriction

The requirement that T cells recognize antigens only when presented on the surface of cells by MHC molecules.

Positive selection in thymus

The process by which T cells that can recognize self-MHC molecules are selected for survival during development.

Negative selection in thymus

The elimination of T cells that bind too strongly to self-peptides presented on MHC, preventing autoimmune reactions.

Anergic cells

T cells that have become unresponsive to their specific antigen due to encountering self-peptides.

Germinal center

The location within secondary lymphoid tissues where activated B cells proliferate and undergo somatic hypermutation.

Affinity maturation

The process by which B cells produce antibodies with increased affinity for their specific antigen over time.

Isotype switching

The process by which B cells change the class of antibody they produce without altering the specificity for the antigen.

Transcytosis of IgA

The process by which IgA antibodies are transported across epithelial cells to mucosal surfaces.

ADCC (Antibody-Dependent Cell-mediated Cytotoxicity)

A mechanism of cell-mediated immune defense whereby antibodies promote the destruction of target cells by Natural Killer (NK) cells.