it is a lymphocytes that plays a large role in humeral immune response.
It also helps in making antibodies.
Memory B cells have the longest lifespan among B-cell types. They are able to persist for years or even decades after an initial exposure to an antigen, providing rapid and robust immune responses upon re-exposure.
there are different types of b cell and t cell. both are lymphocytes, a subclass of white blood cell. the t cells are mainly used in identifying antigens and releasing chemicals which attact macrophages (big immune cells which 'eat' antigens), to destroy the antigen. b cells are used in the production of antibodies. when they encounter a new antigen, plasma cells and memory cells are formed from the division of a b cell. the memory cell remembers the antigen and which antibody to use, while the plasma cell makes the antibodies to fight a particular antigen or class of antigens