Plasma Cell
Definition
A terminally differentiated B cell that has lost most of its surface immunoglobulin and become a high-output antibody factory, secreting thousands of antibody molecules per second. Plasma cells are the source of all circulating antibody and of the antisera produced in forensic immunisation protocols.
- Origin
- Terminally differentiated B cell
- Function
- High-output antibody secretion
- Output
- Thousands of antibody molecules per second
- Forensic relevance
- Source of antisera used in forensic immunisation protocols
Common questions
Why can't a plasma cell respond to a new, different antigen once formed?+
Differentiation into a plasma cell involves losing most surface immunoglobulin and specialising entirely for antibody secretion, so the cell is committed to producing antibody against the antigen that triggered its formation rather than being able to switch targets.
How do plasma cells factor into producing a forensic antiserum?+
An animal is immunised with a target antigen such as human blood protein, and the plasma cells that develop in response secrete large quantities of antibody into the blood, which is then collected and processed into the antiserum used in species or blood-group testing.
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...
- 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...