CD22 NEGATIVELY AND POSITIVELY REGULATES SIGNAL-TRANSDUCTION THROUGH THE B-LYMPHOCYTE ANTIGEN RECEPTOR

The CD22 cell-surface adhesion molecule is capable of modulating B lym phocyte antigen receptor (BCR)-mediated signals, as well as the genera tion of BCR-independent signals. Within the cytoplasmic domain of CD22 are motifs that are structurally homologous to known activation and i nhibitory motifs. These motifs demonstrate physiologic significance vi a associations with known effector proteins that likely mediate their corresponding inhibitory and activation roles. Furthermore, the target ed deletion of CD22 in mice results in phenotypic changes and alterati ons in BCR-mediated signal transduction that are consistent with both positive and negative roles for CD22 in B cell development and activat ion.