Polyarthritis and the air pouch reaction: dissimilarity of adjuvant and collagen models.

The formation of an air pouch in the subcutaneous tissues of a rat previously inoculated intradermally with Freund's mycobacterial adjuvant for the induction of arthritis, provokes a marked but transient inflammatory reaction in the cavity lining of the pouch. The dependence of this reaction on arthritis development was investigated. It was found that rats inoculated with mycobacterial adjuvant by subcutaneous or intraperitoneal injection failed to produce either a pouch reaction or develop arthritis. Intradermal injections of carrageenan, mycobacteria (M. tuberculosis in saline), Freund's incomplete adjuvant alone or containing Salmonella typhimurium lipopolysaccharide and Bordetella pertussis organisms or mycobacterial adjuvant containing egg albumin were also ineffective. Intradermal injections of type II collagen in Freund's incomplete adjuvant did induce arthritis but no pouch reaction; however, this could be elicited after direct challenge with antigen. Pretreatment of rats intraperitoneally with saline suspensions of mycobacteria or a moderate dose of cyclophosphamide prevented both the pouch reaction and arthritis developing to intradermal mycobacterial adjuvant. Pretreatment of rats with mycobacteria was without effect on type II collagen-induced arthritis. From the results of this study it would appear that the air pouch reaction and arthritis induced by adjuvant are directly associated. The inability of collagen to induce a similar reaction demonstrates a fundamental dissimilarity with mycobacterial adjuvant in its mechanism of production of arthritis.