title: Susceptibility to adjuvant-induced arthritis among germfree, specific-pathogen-free, and conventional rats.
abstract: Germfree F344 rats developed severe arthritis with 100% incidence after a single intradermal inection of either squalane containing 0.5 mg of heat-killed Mycobacterium bovis BCG or a water-in-oil emulsion containing 0.2 mg of peptidoglycan derived from Staphylococcus epidermidis. Conventional F344 rats developed less-severe arthritis with 20% incidence for heat-killed BCG and 0% incidence for peptidoglycan. Specific-pathogen-free rats showed an intermediate susceptibility between germfree and conventional rats. Interestingly, both unimmunized specific-pathogen-free and conventional rats. but not unimmunized germfree rats, showed weak delayed-type hypersensitivity reactions to peptidoglycans derived from either S. epidermidis or Lactobacillus plantarum, suggesting that a bacterial flora may furnish a stimulus for induction of cell-mediated immunity to ubiquitous bacterial peptidoglycans. It is thus possible that although a bacterial flora is not necessary for development of adjuvant arthritis, it may have some suppressive effect on the development of the disease in specific-pathogen-free and conventional F344 rats, possibly through modulation of the immune response.
mesh_terms: D000818:Animals; D001168:Arthritis / Q000276:immunology*; D001169:Arthritis, Experimental / Q000175:diagnosis / Q000209:etiology / Q000276:immunology*; D005260:Female; D005856:Germ-Free Life; D006968:Hypersensitivity, Delayed; D007114:Immunization; D007428:Intradermal Tests; D007778:Lactobacillus / Q000276:immunology; D009163:Mycobacterium bovis / Q000276:immunology; D010457:Peptidoglycan / Q000276:immunology; D051381:Rats; D013047:Specific Pathogen-Free Organisms; D013210:Staphylococcus / Q000276:immunology
chemical_list: D010457:Peptidoglycan