Affinity Maturation
Definition
The progressive increase in antibody-antigen binding strength that occurs during the secondary and subsequent responses. It results from somatic hypermutation of immunoglobulin genes in germinal centres and selection for higher-affinity variants. Forensic antisera produced after multiple booster injections benefit from affinity maturation.
- Mechanism
- Somatic hypermutation of immunoglobulin genes
- Site
- Germinal centres
- Selection
- Favours higher-affinity variants
- Occurs during
- Secondary and later immune responses
Common questions
Why does affinity maturation matter for producing forensic antisera?+
Antisera collected after multiple booster injections carry antibodies that have undergone several rounds of affinity maturation, giving stronger and more specific binding than antiserum drawn after only a single immunisation.
Does affinity maturation happen during a first exposure to an antigen?+
It is minimal on a primary response; it becomes prominent on secondary and later exposures, which is why immunisation protocols use repeated booster injections rather than a single dose.
Related terms
- 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...
- Helper T Cell
- A CD4+ T lymphocyte that recognises antigen on MHC class II molecules and secretes cytokines that amplify both the humoral and cellular...
- 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...