We study the cellular and molecular aspects of the antibody mediated immunity. We analyze antibody immune responses elicited against vaccine regimens, gut commensal bacteria and tumors. In particular we are interested in the antibody affinity maturation process on the cellular and molecular levels. We use intravital 2 photon microscopy in living mice, photo labeling, flow cytometer and antibody sequencing methods. Our ultimate goal is to harness our knowledge of the antibody immune response for discovery of new efficient antibodies for diagnostic and human treatment.