Regulatory role of CD19 molecules in B-cell activation and differentiation.
Cluster of differentiation ([CD]) 19 antigens are B-cell-specific molecules expressed on virtually all human cells of the B-lymphocyte lineage except plasma cells. We produced a new anti-CD19 monoclonal antibody (McAb), CLB-CD19, that was used to study the role of CD19 molecules in B-cell activation. Anti-CD19 McAb induced mobilization of free intracellular calcium ([Ca2+]i) in Daudi cells, but not in normal spleen or tonsillar B cells, for which crosslinking with a second anti-mouse Ig antibody was not required. Anti-CD19 McAb inhibited B-cell proliferation induced by anti-IgM coupled to Sepharose beads. This inhibitory effect was overcome by the addition of nonmitogenic concentrations of phorbol myristate acetate. Anti-CD19 McAb did not interfere with Staphylococcus aureus- or B-cell growth factor-induced B-cell proliferation. Anti-CD19 McAb inhibited T-cell-dependent polyclonal B-cell differentiation in pokeweed mitogen-, interleukin 2-, or anti-CD3-driven culture systems. Delayed addition studies showed that once differentiation of B cells was induced, CD19 molecules lost their regulating function. Taken together, our results indicate that CD19 molecules play a regulatory role in B-cell proliferation and differentiation.
de Rie
M A
MA
Central Laboratory, the Netherlands Red Cross Blood Transfusion Service, Amsterdam.
Schumacher
T N
TN
van Schijndel
G M
GM
van Lier
R A
RA
Miedema
F
F
D000888:Antibodies, Anti-Idiotypic / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000917:Antibody Formation; D000918:Antibody Specificity; D000938:Antigen-Presenting Cells / Q000276:immunology; D018941:Antigens, CD19; D000944:Antigens, Differentiation, B-Lymphocyte / Q000276:immunology*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D017252:CD3 Complex; D002118:Calcium / Q000502:physiology; D006801:Humans; D007075:Immunoglobulin M / Q000276:immunology; D015847:Interleukin-4; D007378:Interleukins / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects; D008211:Lymphocyte Cooperation; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D000888:Antibodies, Anti-Idiotypic; D000911:Antibodies, Monoclonal; D018941:Antigens, CD19; D000944:Antigens, Differentiation, B-Lymphocyte; D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D007075:Immunoglobulin M; D007378:Interleukins; D011948:Receptors, Antigen, T-Cell; D015847:Interleukin-4; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium