CD40 and B cell antigen receptor dual triggering of resting B lymphocytes turns on a partial germinal center phenotype.
Phenotypic alterations occur when resting human B lymphocytes become germinal center (GC) cells. These include the induction of surface CD38, CD95 (FAS/APO-1), and carboxy-peptidase-M (CPM), a recently described GC marker. However, the factors that govern the in vivo induction of these surface molecules on B cells remain unknown. Here, we purified resting (CD38-) human B lymphocytes from tonsils in an attempt to establish culture conditions resulting in the induction of these three GC markers. We show that interferon (IFN) alpha or IFN-gamma, as well as antibodies against the B cell antigen receptor (BCR), could induce CD38 on resting B lymphocytes, a phenomenon further enhanced by CD40 stimulation. Concomitantly, CD95 was upregulated by CD40 ligation and, to a lesser extent, by IFN-gamma. By contrast, CPM expression could be upregulated only through BCR triggering. This CPM induction was specifically enhanced by CD19 or CD40 ligation. CD40 + BCR stimulation of resting B cells with CD40 ligand-transfected fibroblastic cells in the presence of cross-linked anti-BCR monoclonal antibodies resulted in the coexpression of CD38, CD95, and CPM. As GC cells, these cells also expressed CD71, CD80 (B7.1), and CD86 (B7.2), but not CD24. However, CD10+ or CD44- B cells could not be detected in these culture conditions, suggesting that yet other signals are required for the induction of these GC markers. Consistent with a GC phenotype, CD40 + BCR-stimulated cells exhibited reduced viability when cultured for 20 h in the absence of stimulus. These results first demonstrate that cotriggering of resting B cells through BCR and CD40 induces both phenotypic and functional GC features. They also show that IFN and CD19 triggering of resting B cells specifically modulate the expression of GC markers.
Galibert
L
L
Schering-Plough, Laboratory for Immunological Research, Dardilly, France.
Burdin
N
N
de Saint-Vis
B
B
Garrone
P
P
Van Kooten
C
C
Banchereau
J
J
Rousset
F
F
D036541:ADP-ribosyl Cyclase; D051997:ADP-ribosyl Cyclase 1; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000096:biosynthesis; D000944:Antigens, Differentiation, B-Lymphocyte / Q000096:biosynthesis*; D001402:B-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D019013:CD40 Antigens / Q000378:metabolism*; D002469:Cell Separation; D002478:Cells, Cultured; D005434:Flow Cytometry; D058851:GPI-Linked Proteins; D018858:Germinal Center / Q000166:cytology / Q000276:immunology*; D006801:Humans; D007156:Immunologic Memory; D007371:Interferon-gamma / Q000494:pharmacology; D008562:Membrane Glycoproteins; D008666:Metalloendopeptidases / Q000096:biosynthesis; D009699:N-Glycosyl Hydrolases / Q000096:biosynthesis; D014066:Palatine Tonsil / Q000166:cytology; D010641:Phenotype; D011947:Receptors, Antigen, B-Cell / Q000378:metabolism*; D019014:fas Receptor / Q000096:biosynthesis
D015703:Antigens, CD; D000943:Antigens, Differentiation; D000944:Antigens, Differentiation, B-Lymphocyte; D019013:CD40 Antigens; D058851:GPI-Linked Proteins; D008562:Membrane Glycoproteins; D011947:Receptors, Antigen, B-Cell; D019014:fas Receptor; D007371:Interferon-gamma; D009699:N-Glycosyl Hydrolases; D036541:ADP-ribosyl Cyclase; C498154:CD38 protein, human; D051997:ADP-ribosyl Cyclase 1; C058479:carboxypeptidase M; D008666:Metalloendopeptidases