The antigen-specific immunoglobulin G receptor is more sensitive to stimulation than the IgM receptor in transfected B cells.
A murine lymphoma cell line (M12.4) was transfected with immunoglobulin (Ig) genes encoding a T15+ (idiotype) IgM antibody or an idiotypically identical IgG antibody. Three transfectant clones of each class which showed similar (albeit distinguishable) levels of membrane expression of the transfected genes were used in the study. The response of each cell population to stimulation with anti-T15 antibodies was followed by measurement of the change in the intracellular Ca++ concentration. The IgG transfectants were found to be significantly more responsive to such stimulation than the IgM cells. In contrast, there was no difference in their response to a nonspecific reagent, the calcium ionophore A23187.
Leung
D T
DT
Department of Physiology, University of Hong Kong.
Loh
T T
TT
Lim
P L
PL
D000818:Animals; D000941:Antigens / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D001483:Base Sequence; D002118:Calcium / Q000378:metabolism; D007075:Immunoglobulin M / Q000502:physiology*; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D011961:Receptors, Fc / Q000502:physiology*; D017452:Receptors, IgG / Q000502:physiology*; D014162:Transfection; D014407:Tumor Cells, Cultured
D000941:Antigens; D007075:Immunoglobulin M; D011961:Receptors, Fc; D017452:Receptors, IgG; C035311:immunoglobulin M receptor; D002118:Calcium