Based on experience, it keeps a memory of those antigens it knows it will probably encounter again and puts more effort into getting rid of antigens it has seen before. B cells B cells look a lot like T cells in their size and shape except they never have granules present in their cytoplasm. B cells were first identified in birds and found associated with this organ. Conveniently B can also stand for bone marrow where B cells mature in non-bird species like ourselves. In humans, B cells are released into the blood stream from the bone marrow as fully functioning adult cells.
B cells are of course antibody producing cells.
Most B cells situate themselves in immune organs such as the spleen and wait for their activation. Like T cells each B cell is only able to respond to one specific antigen and each B cell responds to a different antigen. The B cells have antibody on their cell surface which acts as the receptors for antigen. B cells can receive stimulation in two ways. Typically most antigens are first processed by antigen presenting cells and then presented to the B cells at the same time as presentation to Th cells.