Description: The MB19-1 monoclonal antibody reacts with mouse CD19, a 95 kDa transmembrane glycoprotein. CD19 is expressed by B cells during all stages of development excluding the terminally differentiated plasma cells. Follicular dendritic cells also express CD19. Together CD21, CD81, MHC class II, and CD19 form a multimolecular complex that associates with the BCR. Signaling through CD19 induces tyrosine phosphorylation, calcium flux and proliferation of B cells. Staining of B cells with MB19-1 and its conjugates is usually dimmer than the rat anti-mouse CD19 antibody, clone 6D5.