Fish Immunology (1+1)

Unit 10 - Immunological Memory

10.2. Recognition
The immune system uses a large number of highly specific B and T cells to
recognize antigen. The number of possible distinct antigens is to be in the range 1012 to 1016. B and T cell receptors are stimulated by antigen. Typically around105 B cells of an individual are stimulated by antigens. B-cells that are activated but not differentiate into plasma cells are transformed into memory B-cells. These memory cells can provide memory for longer period.
This was explained by theories like:-

• Memory cells live for a long time
• Memory cells are restimulated at some low level
• Small amounts of the antigen are retained in lymph nodes
• Related environmental antigens provide cross-stimulation