Does B-Lymphocyte considered as antigen presenting cell or not ?

Question

in relation to its immunological function beside production of anti-bodies ?

Answer 1

I think B-lymphocyte is considered as APC . B cells, which express antibody, can very efficiently present the antigen to which their antibody is directed, but are inefficient APC for most other antigens.

http://en.wikipedia.org/wiki/Antigen_presenting_cell

Answer 2

Class I MHC proteins are on ALL cells in the body (except mature RBCs, which no longer have a nucleus), including APCs. These sites display fragments of the cell's own proteins on their surfaces - and any other proteins that were made inside the cell, such as proteins of an infecting virus. The "foreign" proteins of an infecting virus are recognized by cytotoxic T-lymphocytes, which then destroy the infected cells. Class II proteins are present only on APCs (and helper T lymphocytes). Class II MHC sites display protein fragments produced from phagocytosed cells, such as bacteria. Recognition of those "foreign" proteins by helper T-cells causes them to stimulate production of an immune response. I'm not sure what you mean by your "advantage" question . . .