Q.State whether the following statement is True or False: Memory cells produce antibodies or kill infected cells.

Memory cells are long-lived 'recognition' cells; antibody production and killing are carried out by plasma cells and cytotoxic T cells respectively.

When the immune system first encounters an antigen, some of the activated B and T lymphocytes differentiate into memory cells instead of effector cells. Memory cells do not actively secrete antibodies or kill infected cells during the primary response — they simply persist in the body for a long time (sometimes lifelong), 'remembering' the antigen. On re-exposure to the same antigen, they rapidly prol …

Part (a): The principle of vaccination is based on immunological MEMORY - option (C). Part (b): Opioids act as PAIN KILLERS (analgesics) - option (B).