Origin of Plasma Cells

Plasma cells are derived from:

Correct Answer: B-lymphocytes

Plasma cells (also called plasmocytes) are derived from B-lymphocytes upon antigen stimulation and T-helper cell activation. They are the antibody-secreting cells of the immune system.

B-lymphocyte Differentiation

• B-lymphocytes mature in the bone marrow.
• Upon antigen encounter + T-helper cell stimulation → B cells proliferate and differentiate into:
• Plasma cells: Short-lived, highly active antibody factories; produce 2,000 antibody molecules per second.
• Memory B cells: Long-lived cells responsible for anamnestic (secondary) immune response.

Plasma Cell Features

• Cartwheel (clock-face) nucleus: Distinctive morphology — heterochromatin arranged in a spoke-like pattern along the nuclear membrane.
• Eccentric nucleus with abundant rough ER (for antibody protein synthesis).
• Produce immunoglobulins (IgG, IgM, IgA, IgD, IgE).

Example

• When a cow receives a vaccine against FMD → B-lymphocytes recognise FMD antigens → differentiate into plasma cells → secrete specific antibodies against FMD virus → protective immunity.