Expression of CD38 during ontogeny of murine B cells. (36.59)

Abstract

CD38 is a 45 KD transmembrane protein, expressed by immature and mature lymphocytes. Agonistic antibodies directed to this molecule induce several biological responses: cellular proliferation, protein phosphorylation, intracellular Ca2+ mobilization, rescue from and induction of apoptosis. CD38 ligation with a mAb anti-CD38 (NIM-R5) induces apoptosis of the murine pro-B cell line (Ba/F3); this phenomenon depends on tyrosine kinases activation and the MAP kinase ERK. The expression and function of CD38 during B-cell ontogeny has been poorly analyzed in mice. We analyzed the expression of CD38 during the ontogeny of B cells in murine bone marrow. Bone marrow cells from C57BL/6J mice were stained with antibodies against: CD19, CD45R, IgM, CD43 and CD38. The samples were captured in a Beckman coulter’s CyAn flow cytometer and each subpopulation was analyzed with FlowJo v.7.5 software. CD38 is expressed from the preproB stage. ProB, preB and immature B cells from murine bone marrow were all positive for the expression of CD38, but immature B cells had the highest fluorescence intensity. The results suggest that CD38 may play a role during the ontogeny of murine B cells. Then, the next step is to analyze whether CD38 ligation on these subpopulations, induces proliferation, maturation or apoptosis.