Enhancement of human B cell proliferation by an antibody to the C3d receptor, the gp 140 molecule.
The C3d receptor is a specific marker of B lymphocytes. Recently we have shown that C3d receptor activity is carried by a gp 140 membrane antigen. A polyclonal antibody has been prepared by immunizing a rabbit with highly purified gp 140 molecule isolated from membranes of the human B lymphoblastoid cell line Raji and its high specificity was previously demonstrated. We tested the effect of this antibody to the C3d receptor on the B cell proliferative response. Purified B cells from human blood were induced to proliferate by a B cell growth factor (BCGF)-containing partially purified supernatant from activated T cells. The anti-C3d receptor F(ab')2 enhanced the BCGF-dependent B cell proliferation. This effect was dose dependent, was observed in the presence of different concentrations of BCGF and did not correspond to a change in the time course of the response. The anti-C3d receptor F(ab')2 had no mitogenic effect in the absence of T cell supernatant. In contrast the undigested anti-C3d receptor IgG suppressed the BCGF-dependent B cell proliferation. These results emphasize the potentialities of anti-gp 140 F(ab')2 to explore the involvement of the C3d receptor in the regulation of B cell response to T cell products.
Frade
R
R
Crevon
M C
MC
Barel
M
M
Vazquez
A
A
Krikorian
L
L
Charriaut
C
C
Galanaud
P
P
D000276:Adjuvants, Immunologic / Q000502:physiology*; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D006133:Growth Substances / Q000494:pharmacology; D006801:Humans; D007108:Immune Tolerance; D007140:Immunoglobulin Fab Fragments / Q000502:physiology; D007074:Immunoglobulin G / Q000502:physiology*; D015847:Interleukin-4; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000494:pharmacology; D008970:Molecular Weight; D011817:Rabbits; D011951:Receptors, Complement / Q000276:immunology*; D017464:Receptors, Complement 3d
D000276:Adjuvants, Immunologic; D006133:Growth Substances; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D008222:Lymphokines; D011951:Receptors, Complement; D017464:Receptors, Complement 3d; D015847:Interleukin-4