Helper T cell
Definition
A CD4+ T lymphocyte that recognises antigen on MHC class II molecules and secretes cytokines that amplify both the humoral and cellular arms of the immune response. Without helper T cell activation, B cells cannot mount a full antibody response to protein antigens.
Related terms
- Affinity maturation
- The progressive increase in antibody-antigen binding strength that occurs during the secondary and subsequent responses. It results from somatic hypermutation of immunoglobulin...
- Clonal selection
- The process by which an antigen binds selectively to the lymphocyte (B or T cell) that carries the complementary surface receptor, triggering...
- Cytotoxic T cell (CTL)
- A CD8+ T lymphocyte that recognises peptide antigens presented on MHC class I molecules and kills the target cell by releasing perforin...
- Memory B cell
- A long-lived B cell generated during a primary immune response that retains the antigen-specific receptor and persists in lymphoid tissue. On re-exposure...
- Plasma cell
- A terminally differentiated B cell that has lost most of its surface immunoglobulin and become a high-output antibody factory, secreting thousands of...
Explained in
- Humoral and Cellular Immune Response MechanismsA CD4+ T lymphocyte that recognises antigen on MHC class II molecules and secretes cytokines that amplify both the humoral and cellular arms of the immune resp...