title: Cutaneous unresponsiveness to Mycobacterium bovis BCG in intravenously infected mice.
abstract: Mice injected with 1 mg (about 1 X 10(7) CFU) of Mycobacterium bovis BCG in the footpad showed high levels of delayed-type hypersensitivity (DTH) to BCG antigens and a continuous increase in circulating specific anti-immunoglobulin G (IgG) antibodies throughout a 6-week observation period. In contrast, mice injected intravenously with a 1-mg dose failed to mount a DTH and showed a depression in antibody production at week 5 postinfection. A dose-response study revealed that an optimum dose of BCG, when injected intravenously, can induce a small but significant DTH response. The delayed cutaneous unresponsiveness in intravenously infected mice lasted at least 6 weeks and was not antigenically specific, in that it depressed the DTH response to Corynebacterium parvum. No simple relationship existed between levels of DTH and the amount of circulating anti-IgG antibodies. Splenectomy and treatment with a high dose of cyclophosphamide before infection, although greatly reducing the humoral response, did not reverse the BCG-induced unresponsiveness nor enhance levels of DTH in mice infected in the footpad. It is concluded that the intravenous infection of mice with BCG exerts a nonspecific inhibitory effect on delayed-type immune reactions by the induction of some type of suppressor mechanisms that are resistant to cyclophosphamide.
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000032:analysis; D001500:BCG Vaccine / Q000276:immunology*; D003352:Corynebacterium / Q000276:immunology; D003520:Cyclophosphamide / Q000276:immunology; D004306:Dose-Response Relationship, Immunologic; D005260:Female; D006968:Hypersensitivity, Delayed / Q000276:immunology; D007114:Immunization; D007275:Injections, Intravenous; D051379:Mice; D008810:Mice, Inbred C57BL; D009163:Mycobacterium bovis / Q000276:immunology*; D012867:Skin / Q000276:immunology*; D013154:Spleen / Q000276:immunology; D013156:Splenectomy; D014376:Tuberculosis / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D001500:BCG Vaccine; D003520:Cyclophosphamide