Human peripheral blood T helper cell-induced B cell activation results in B cell surface expression of the CD23 (BLAST-2) antigen.
We have developed an in vitro system to assess the early stages of B cell activation induced by peripheral blood T helper cells. Peripheral blood mononuclear cells are cultured for 16 hr with anti-CD3 monoclonal antibody (mAb), T lymphocytes are then removed by sheep red blood cell rosette depletion, and expression of the B cell surface activation antigen CD23 (BLAST-2) is assessed by indirect immunofluorescence. Anti-CD3 mAb, but not a control anti-CD5 mAb, stimulates the expression of CD23 on 20-50% of peripheral blood B cells cultured with autologous T cells. T cell subset depletion studies show that the CD4+ T cell subset is responsible for anti-CD3-mediated induction of CD23 on autologous B cells. Anti-CD3-induced, T helper cell-dependent CD23 expression is not MHC-restricted, as allogeneic combinations of T and non-T cells, cultured in the presence of anti-CD3 antibody, also result in the expression of B cell CD23. Individuals whose monocyte Fc receptors bind murine IgG1 mAb poorly fail to trigger T cell proliferation in response to murine IgG1 anti-CD3 mAb and also fail to express B cell CD23 following culture of PBMC with IgG1 anti-CD3 mAb, while the usual expression of CD23 is seen after culture with IgG2a anti-CD3 mAb. The mechanism of anti-CD3-induced B cell activation was addressed in experiments using a two-chamber culture system. While little IL-4 activity was detected in anti-CD3-stimulated culture supernatants, optimal induction of CD23 was observed when T and B cells were cultured together in a single chamber. This suggests that under physiologic conditions, in which quantities of lymphokine may be limiting, close physical contact between the anti-CD3-activated Th cell and B cell may be required for CD23 expression. The anti-CD3-induced BLAST-2 assay will facilitate the analysis of Th cell-mediated B cell activation in any individual and should permit us to separately evaluate the roles of Th cells and B cells in the impaired immunoregulation characteristic of autoimmune disorders.
Crow
M K
MK
Department of Medicine, Hospital for Special Surgery, New York, New York.
Kushner
B
B
Jover
J A
JA
Friedman
S M
SM
Mechanic
S E
SE
Stohl
W
W
D000911:Antibodies, Monoclonal; D000944:Antigens, Differentiation, B-Lymphocyte / Q000096:biosynthesis*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D017252:CD3 Complex; D002478:Cells, Cultured; D002999:Clone Cells; D003470:Culture Media; D006681:HLA-D Antigens / Q000276:immunology; D006801:Humans; D015847:Interleukin-4; D007378:Interleukins / Q000032:analysis; D008213:Lymphocyte Activation; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000502:physiology*
D000911:Antibodies, Monoclonal; D000944:Antigens, Differentiation, B-Lymphocyte; D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D003470:Culture Media; D006681:HLA-D Antigens; D007378:Interleukins; D011948:Receptors, Antigen, T-Cell; D015847:Interleukin-4