Signal transduction through the CD19 receptor during discrete developmental stages of human B-cell ontogeny.

摘要: We present evidence that the CD19 receptor is functionally operative and transmits pleiotropic signals throughout pro-B, pre-pre-B, pre-B, early B, mature B cell stages of human B-cell ontogeny. The signaling ability does not depend on existence a functional antigen complex (ARC). In precursors (BCP) lacking ARC, physically associated with Src family protein tyrosine kinases (PTK). engagement BCP high affinity anti-CD19 monoclonal antibody (mAb) or its homoconjugate rapidly activates PTK results in phosphorylation CD19. Moreover, this proximal activation step triggers downstream stimulation several different intracellular messenger systems. Remarkably, becomes phosphorylated residues upon other surface receptors as well, suggesting it may function common response element linked via to multiple BCP/B-cell pathways. Furthermore, all B-lineage lymphoid populations, co-approximation CD72 (ligand for CD5 T-cell receptor) generates stronger signal than either individual receptor. These convergent observations constitute strong argument an important regulatory prompt hypothesis play role cognate interactions between B- T-lineage compartments well coordinate production at