Lymphocyte Development and Antigen Presentation

Vocabulary flashcards covering lymphocyte maturation, clonal selection/deletion, and the two types of antigen processing.

B cells

Lymphocytes that remain in the bone marrow for maturation and development.

T cells

Lymphocytes that migrate to the thymus for differentiation and maturation.

Naïve cells

T and B cells that have migrated to secondary lymphoid tissues but have not yet encountered an antigen.

Clonal deletion

The destruction of self-clones to create tolerance in the immune system.

Clone

Each genetically different type of lymphocyte that expresses a single specificity because of its unique receptor.

Clonal selection

The process by which the first introduction of an antigen into the immune system "selects" a lymphocyte genetically programmed for that specific antigen.

Clonal expansion

The process where a specific selected lymphocyte expands its population into clones of cells that can react to a particular antigen.

Exogenous antigen processing

The process where Class II binds to antigen fragments that come from outside the cell and present to CD4+ T-helper cells.

Endogenous antigen processing

The process where Class I binds to antigen peptides originating in the cytoplasm and presents them to CD8+ T cells.

Class II

A marker that binds to antigen fragments coming from outside the cell to present them to CD4+ T-helper cells.

Class I

A marker that binds to antigen peptides originating in the cytoplasm (including self-antigens, viral fragments, or cancerous markers) to present them to CD8+ T cells.

CD4+ T-helper cells

T cells that receive presented antigen fragments from Class II molecules during exogenous processing.

CD8+ T cells

T cells that receive presented antigen peptides from Class I molecules during endogenous processing.