title: Antibodies to immune response gene products inhibit the IgM and IgG antibody response but not the development of resistance to Toxoplasma gondii.
abstract: We have examined the effects of a monoclonal antibody directed against immune response gene products on the appearance of antibodies and development of resistance to Toxoplasma gondii. In vivo administration of a single dose of anti-I-Ak antibody to C3H/He (H-2k) and not BALB/c (H-2d) mice suppressed both the IgM and IgG response to two different strains of Toxoplasma. Administration of anti-I-Ak antibody to mice 5 days before and 10 days after infection resulted in complete inhibition of IgM and a more pronounced inhibition of IgG response to Toxoplasma. Under these experimental conditions, development of resistance against a subsequent challenge with a virulent strain of Toxoplasma was not affected. The microbicidal and tumoricidal activities of macrophages obtained from anti-I-Ak-treated, Toxoplasma-infected mice and mice infected with Toxoplasma alone were equivalent. Mice treated with anti-I-Ak antibody demonstrated a decreased proliferative response to lipopolysaccharide, a B-cell mitogen. Enumeration of B-cell numbers in anti-I-Ak-treated mice revealed a pronounced decrease in B-cell counts.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D005260:Female; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D007074:Immunoglobulin G / Q000032:analysis*; D007075:Immunoglobulin M / Q000032:analysis*; D008213:Lymphocyte Activation; D008264:Macrophages / Q000276:immunology; D051379:Mice; D008815:Mice, Inbred Strains; D014124:Toxoplasmosis, Animal / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000949:Histocompatibility Antigens Class II; D007074:Immunoglobulin G; D007075:Immunoglobulin M