Pristane-induced arthritis in mice selected for maximal or minimal acute inflammatory reaction

The role of inflammatory and specific immune responses in pristane-induced arthritis (PIA) was investigated in mouse lines produced by bi-directional selective breedings for maximal (AIRmax) or minimal (AIRmin) acute inflamma tory reaction, comparing the outcome of PIA and the humoral and cellular re sponse to hsp65. Symptoms of arthritis were detected in 50 % AIRmax mice 12 0 days after pristane injection, reaching a maximal incidence of 65 %, wher eas only 7 % of AIRmin mice developed arthritis within an observation perio d of 200 days. The production of IgG antibody against hsp65 was found to be similar on both lines, although the IgG1 Isotype was predominant in AIRmax , and IgG2a in AIRmin line. In vitro T cell proliferation to hsp65 was simi lar in the two lines, however, ELISPOT assays carried out soon after prista ne treatment, demonstrated higher numbers of IL-6-, TNF-alpha- and IL-4-sec reting cells in the spleen of AIRmax than in AIRmin mice, while higher numb ers of IFN-gamma-producing cells were found in AIRmin mice. These results s uggest a major participation of acute inflammatory mechanisms in the suscep tibility to PIA. The genetic background which determines high or low AIR fa vors a Th2-like response in susceptible AIRmax and Th1-like response in res istant AIRmin mice at the initial phase of arthritis induction.