Adjuvant Polyarthritis. VII. The Role of Type II Collagen in Pathogenesis

The development of immune response in rats directed toward EL4 cells, after the injection of EL4 cells suspended in a saline/oil emulsion, was enhanced by the incorporation of Mycobacterium into the saline/oil emulsion; the incorporation of type II collagen into the saline-acetic acid/oil emulsion in concentrations ranging from 0.5-25 micrograms/ml had no apparent effect on the development of immune response. The incorporation of type II collagen into the saline-acetic acid/oil emulsion at higher concentrations (100 micrograms and 1.0 mg/ml) significantly suppressed both the humoral and the cell-mediated immune response. Pretreatment of rats with the maximal subarthritiogenic dose of complete Freund's adjuvant prevented the development of arthritis in response to a subsequent injection of an arthritogenic dose of the same adjuvant, but had no effect on the development of type II collagen-induced arthritis. These observations suggest that adjuvant arthritis and the type II collagen-induced arthritis are distinctly different diseases.