Collagen-induced arthritis in Biozzi mice. Joint involvement is not correlated with collagen II IgG2a autoantibodies nor restricted to only H-2q and H-2r.

High (H) and low (L) immune responder "Biozzi" mice, obtained by four different selections, were investigated for their ability to develop collagen-induced arthritis. Both LI and LII lines--characterized by their low antibody responses to a wide variety of Ag--developed arthritis though they do not bear the susceptible H-2q and H-2r haplotypes. Out of the two lines (HI and HII) selected for their high antibody responses and bearing H-2q, only one (HI) developed arthritis. Both the lines with amplified high or low antibody responses (HG and LG), and the lines differing in the levels of cell-mediated immunity (Hpha and Lpha), failed to develop arthritis. Collagen II autoantibodies were found in all the lines: the responses being high (HI and HG), low (LI, LII and LG), or intermediate (HII, Hpha and Lpha). The level of IgG2a autoantibodies, presumed to be the most pathogenic, was low in two (HI and LII) of the three arthritic lines, and was high in the unaffected HG line. These results show that this arthritis is not solely restricted to H-2q and H-2r haplotypes, and argue against a correlation between collagen autoantibody levels and disease incidence.