Immunization with live versus killed Salmonella typhimurium leads to the generation of an IFN-gamma-dominant versus an IL-4-dominant immune response.
The mechanisms responsible for differential commitment of effector T cells to the production of either the IL-4/5/10 group or to the IL-2/IFN-gamma group of lymphokines during an immune response have not yet been clearly elucidated. We have used Salmonella typhimurium as a model murine bacterial parasite in BALB/c mice for live-cell versus killed-cell immunization and looked at the immune response in terms of delayed type hypersensitivity (DTH), IgG subclass distribution in the serum antibody response, and antigen-specific T cell proliferation and lymphokine secretion. The results indicate that the two forms of immunogen induce qualitatively different immune responses. Intraperitoneal immunization with live bacteria induces an IFN-gamma-dominant immune response associated with a strong DTH reaction and relatively higher levels of specific antibodies belonging to the IFN-gamma-dependent IgG2a isotype rather than the IL-4-dependent IgG1 isotype. Immunization with heat-killed bacteria gives rise to an IL-4-dominated response that shows excellent proliferative capacities in vitro, with lower levels of DTH responses and comparatively high levels of specific antibodies of the IgG1 isotype. IL-2 production in the responses generated by the two modes of immunization, however, is not preferentially associated with IFN-gamma production, unlike the reported profiles of long-lived murine T cell clones in vitro.
Thatte
J
J
National Institute of Immunology, New Delhi, India.
Rath
S
S
Bal
V
V
D000818:Animals; D000917:Antibody Formation; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000276:immunology*; D002455:Cell Division / Q000276:immunology; D002478:Cells, Cultured; D006968:Hypersensitivity, Delayed; D007371:Interferon-gamma / Q000096:biosynthesis*; D007376:Interleukin-2 / Q000096:biosynthesis; D015847:Interleukin-4 / Q000096:biosynthesis*; D051379:Mice; D008807:Mice, Inbred BALB C; D012486:Salmonella typhimurium / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology; D015164:Vaccines, Inactivated / Q000276:immunology
D001428:Bacterial Vaccines; D007376:Interleukin-2; D015164:Vaccines, Inactivated; D015847:Interleukin-4; D007371:Interferon-gamma