Membrane IgM, IgD, and IgG act as signal transmission molecules in a series of B lymphomas.
Increases in intracellular free calcium concentration ((Ca2+)i) were observed in response to anti-immunoglobulin (Ig) antibodies in each of six B cell tumors or B cell hybridomas bearing mu or delta chains on their cell surface. The BAL17 cell line, bearing mu and delta chains on its surface, behaved similarly to mature B cells in the following respects. Anti-IgM and anti-IgD antibodies caused increases in (Ca2+)i and inositol phospholipid metabolism; the initial increases in (Ca2+)i were derived partly from an intracellular Ca2+ pool; lipopolysaccharide, phorbol myristate acetate (PMA), B cell stimulatory factor-1, and antibodies to class I and class II major histocompatibility molecules and to the Fc gamma receptor failed to cause increases in (Ca2+)i or in inositol phospholipid metabolism; and increases in (Ca2+)i and inositol phospholipid metabolism in response to anti-Ig were inhibited by pretreatment with PMA. Furthermore A20, an IgG2a bearing lymphoma, showed increases in (Ca2+)i in response to anti-IgG2a, and a lymphoma cell line (6G8-2E10) expressing membrane IgG2b as a result of DNA-mediated transfer of the gamma 2b H chain gene, showed increases in (Ca2+)i in response to anti-IgG2b. These results indicate that Ig-bearing lymphomas display early events in B cell activation after receptor cross-linkage and can be used for detailed studies of the activation process.
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D002118:Calcium / Q000502:physiology; D003001:Cloning, Molecular; D004533:Egtazic Acid / Q000494:pharmacology; D007072:Immunoglobulin D / Q000502:physiology; D007074:Immunoglobulin G / Q000502:physiology; D007075:Immunoglobulin M / Q000502:physiology; D007295:Inositol Phosphates / Q000378:metabolism; D008223:Lymphoma / Q000276:immunology*; D051379:Mice; D010716:Phosphatidylinositols / Q000502:physiology; D011947:Receptors, Antigen, B-Cell / Q000502:physiology*; D014162:Transfection
D007072:Immunoglobulin D; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007295:Inositol Phosphates; D010716:Phosphatidylinositols; D011947:Receptors, Antigen, B-Cell; D004533:Egtazic Acid; D002118:Calcium