Induction of IgG3 secretion by interferon gamma: a model for T cell-independent class switching in response to T cell-independent type 2 antigens.
T cell-independent type 2 (TI-2), in contrast to T-dependent, antigens stimulate the production of murine IgG3. To investigate a possible role for cytokines in mediating the induction of this IgG subclass, we established an in vitro polyclonal model system for studying TI-2 antigen-mediated B cell activation by using dextran-conjugated anti-IgD antibody (alpha delta-dex). We demonstrate that interferon gamma (IFN-gamma) stimulates, and interleukin 4 inhibits, the expression of IgG3 by alpha delta-dexactivated cells. The production of IFN-gamma by non-T cells in response to bacterial products, possibly capsular polysaccharides, may provide an explanation underlying the ability of TI antigens, which are unable to directly stimulate T cell-derived cytokines to induce Ig isotype switching.
Snapper
C M
CM
Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814.
McIntyre
T M
TM
Mandler
R
R
Pecanha
L M
LM
Finkelman
F D
FD
Lees
A
A
Mond
J J
JJ
D000818:Animals; D000940:Antigenic Variation; D000955:Antigens, T-Independent / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology; D002478:Cells, Cultured; D003911:Dextrans; D005260:Female; D005434:Flow Cytometry; D007072:Immunoglobulin D / Q000276:immunology; D007074:Immunoglobulin G / Q000378:metabolism*; D007371:Interferon-gamma / Q000502:physiology*; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D008954:Models, Biological; D013601:T-Lymphocytes / Q000276:immunology
D000955:Antigens, T-Independent; D003911:Dextrans; D007072:Immunoglobulin D; D007074:Immunoglobulin G; D007371:Interferon-gamma