T-HELPER SUBSET INVOLVEMENT IN 2 HIGH ANTIBODY RESPONDER LINES OF MICE (BIOZZI MICE) - HI (SUSCEPTIBLE) AND HII (RESISTANT) TO COLLAGEN-INDUCED ARTHRITIS

CD4(+) T helper cells play a critical role in the chronicity of collag en-induced arthritis (CIA) in mice. The present results focus on the i nvolvement of Th1 and Th2 subsets at the initial stage of the experime ntal disease in two lines of mice selected for high antibody productio n: HI that is susceptible, and HII that is resistant to CIA. Both line s are known to be H-2(q), display an identical full set of V-beta gene s, and mount similar antibody responses to both heterologous and autol ogous CII. The kinetic analysis of local T cell and anti-bovine CII an tibody responses was followed by Elispot assays, the production of int erferon-gamma (IFN-gamma) and IgG2a being considered indicative of a T h1 profile, and interleukin-5 (IL-5) as well as IgG1-IgE, of a Th2 pro file. The number of IL-5 Elispots is constantly higher in susceptible than in resistant mice. The IFN-gamma production is rather low in HI c ompared to HIl, and besides, preferential help is observed for the Th2 -dependent IgG1-IgE isotype-producing B cells in HI, while a switch-ov er toward IgG2a anti-CII isotype is found in HII. These results sugges t that a Th1 preeminence at the onset of the anti-CII response is deci sive in the resistance to CIA.