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

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...

CD19 and CD22 regulate a B lymphocyte signal transduction pathway that contributes to autoimmunity.

The fate of B lymphocytes is dependent on intrinsic and B cell antigen receptor (BCR)-induced signals. These signals are modified and interpreted by other cell-surface molecules such as CD19 and CD22 that govern mature B cell activation. This review assesses our current understanding of how CD19 and CD22 regulate B lymphocyte signaling and how alterations in these response-regulators contribute...

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...

CD19 amplifies B lymphocyte signal transduction by regulating Src-family protein tyrosine kinase activation.

Ligation of the B cell Ag receptor (BCR) induces cellular activation by stimulating Src-family protein tyrosine kinases (PTKs) to phosphorylate members of the BCR complex. Subsequently, Src-family PTKs, particularly Lyn, are proposed to phosphorylate and bind CD19, a cell-surface costimulatory molecule that regulates mature B cell activation. Herein, we show that B cells from CD19-deficient mic...