CD19 Amplification of B Lymphocyte Ca2+ Responses

CD19 amplification of B lymphocyte Ca2+ responses: a role for Lyn sequestration in extinguishing negative regulation.

B lymphocyte antigen receptor (BCR) signals are regulated by CD19, with BCR-induced intracellular calcium ([Ca(2+)](i)) responses enhanced by CD19 co-ligation. In this study, CD19 engagement using a dimeric anti-CD19 antibody induced [Ca(2+)](i) mobilization and significantly enhanced BCR-induced [Ca(2+)](i) responses without a requirement for CD19/BCR co-ligation. Although simultaneous CD19 an...

B lymphocyte antigen receptor signaling: initiation, amplification, and regulation

B lymphocytes and their differentiated daughters are charged with responding to the myriad pathogens in our environment and production of protective antibodies. A sample of the protective antibody produced by each clone is utilized as a component of the cell's antigen receptor (BCR). Transmembrane signals generated upon antigen binding to this receptor provide the primary directive for the cell...

The CD19 signal transduction molecule is a response regulator of B-lymphocyte differentiation.

The phenotypes of CD19-deficient (CD19-/-) mice, and human CD19-transgenic (hCD19TG) mice that overexpress CD19 indicate that CD19 is a response regulator of B-lymphocyte surface receptor signaling. To further characterize the function of CD19 during B-cell differentiation, humoral immune responses to a T-cell-independent type 1 [trinitrophenyl-lipopolysaccharide (TNP-LPS)], a T-cell-independen...

Activation Transduction Independent of Complement CD19 Can Regulate B Lymphocyte Signal

CD19 can regulate B lymphocyte signal transduction independent of complement activation.

B lymphocytes are critically regulated by signals transduced through the CD19-CD21 cell surface receptor complex, where complement C3d binding to CD21 supplies an already characterized ligand. To determine the extent that CD19 function is controlled by complement activation, CD19-deficient mice (that are hyporesponsive to transmembrane signals) and mice overexpressing CD19 (that are hyperrespon...