Merck, MAB1217F, Anti-FMC-7 B-Cell Lymphocyte Marker Antibody, clone FMC-7, FITC conjugated

B cells are lymphocytes that play a large role in the humoral immune response as opposed to the cell-mediated immune response that is governed by T cells. The principal function of B cells is to make antibodies against soluble antigens. B cells are an essential component of the adaptive immune system. FMC-7 B-Cell Lymphocyte Marker is a 105 kDa B cell restricted antigen which is expressed on about 50% of adult human peripheral blood B cells. Upon in vivo B cell activation FMC7 expression initially increases. B cells involved in antibody secretion have lost the FMC7 determinant. The monoclonal antibody FMC7 delineates a subpopulation of B lymphocytes in normal blood. Expression of the antigen recognized by FMC7 appears to be maturation-linked, and it serves to distinguish different types of B cell leukemia.