title: Regulation of I-A expression by murine peritoneal macrophages: differences linked to the Bcg gene.
abstract: We previously reported that Mycobacterium bovis (strain BCG) induces continuous I-A expression when injected into BCG-resistant strains of mice. We have extended this observation by showing that Corynebacterium parvum also induces continuous I-A expression by macrophages from BCG-resistant but not BCG-susceptible mice. We have linked continuous expression to BCG resistance by using C.D2Ityr mice, which are congenic with BCG-susceptible BALB/c mice except for genes on a portion of chromosome 1, which contains the gene(s) for BCG resistance. Macrophages from C.D2Ityr mice continuously expressed I-A, whereas macrophages from BALB/c mice transiently expressed I-A. Continuous expression by macrophages from both Bcgr and Bcgs mice could be induced in vitro with rIFN-gamma. However, the continuous expression of I-A by macrophages from Bcgs mice required the continued presence of IFN-gamma, whereas that by Bcgr macrophages did not. The continuous expression of I-A by macrophages from Bcgs mice was also inhibited by hydrocortisone, cyclohexamide, tunicamycin, and monensin, whereas I-A expression by Bcgr macrophages was not affected. The continuous expression of I-A by macrophages from Bcgr mice did not require its continued synthesis. The significance of these findings to the induction of immunity and to antimicrobial resistance are discussed.
mesh_terms: D000818:Animals; D002874:Chromosome Mapping; D003513:Cycloheximide / Q000494:pharmacology; D005786:Gene Expression Regulation; D000949:Histocompatibility Antigens Class II / Q000235:genetics*; D006854:Hydrocortisone / Q000494:pharmacology; D008264:Macrophages / Q000276:immunology*; D051379:Mice; D008985:Monensin / Q000494:pharmacology; D009163:Mycobacterium bovis / Q000276:immunology*; D010529:Peritoneal Cavity / Q000166:cytology; D011425:Propionibacterium acnes / Q000276:immunology; D014415:Tunicamycin / Q000494:pharmacology
chemical_list: D000949:Histocompatibility Antigens Class II; D014415:Tunicamycin; D008985:Monensin; D003513:Cycloheximide; D006854:Hydrocortisone