What are memory B cells?

What are memory B cells?

• A. B-cells that produce antibodies only during primary response.
• B. B-cells that present antigens to T cells.
• C. B-cells that stay in the blood stream indefinitely.
• D. B-cells that remain in lymphatic tissue after activation.

Answer: (D)

Memory B cells are long-lived descendants of B cells that were activated during the first exposure to an antigen. After the initial response, some activated B cells become plasma cells that secrete antibodies, while others become memory B cells that persist in lymphoid tissues such as lymph nodes and the spleen (and can circulate). They have undergone affinity maturation and isotype switching, so they carry high-affinity, isotype-switched B-cell receptors. When the same antigen is encountered again, memory B cells rapidly reactivate, proliferate, and differentiate into antibody-secreting plasma cells, producing a quicker and stronger secondary antibody response. This is why staying in lymphoid tissue after activation accurately reflects their persistence and readiness for future encounters.

Memory B cells are long-lived descendants of B cells that were activated during the first exposure to an antigen. After the initial response, some activated B cells become plasma cells that secrete antibodies, while others become memory B cells that persist in lymphoid tissues such as lymph nodes and the spleen (and can circulate). They have undergone affinity maturation and isotype switching, so they carry high-affinity, isotype-switched B-cell receptors. When the same antigen is encountered again, memory B cells rapidly reactivate, proliferate, and differentiate into antibody-secreting plasma cells, producing a quicker and stronger secondary antibody response. This is why staying in lymphoid tissue after activation accurately reflects their persistence and readiness for future encounters.