Beschreibung:
<jats:title>Abstract</jats:title><jats:p><jats:italic>Objective.</jats:italic> To test for genetic differences in susceptibility to homologous (rat) type II collagen‐induced arthritis (RII‐CIA).</jats:p><jats:p><jats:italic>Methods.</jats:italic> Nine inbred and RT1‐congenic rat strains were immunized with native rat type II collagen and evaluated for arthritis and IgG anti‐RII serum antibody titers.</jats:p><jats:p><jats:italic>Results.</jats:italic> Only RT1<jats:sup>av1</jats:sup> strains developed a high incidence of severe RII‐CIA and high titers of IgG anti‐RII serum antibody. Rats having RII‐CIA‐resistant haplotypes, RT1<jats:sup>u,n,1</jats:sup> (which are known to develop CIA after immunization with heterologous type II collagen), were shown to also be susceptible to passive transfer of CIA with immune serum concentrates. Clinical expression of RII‐CIA was down‐regulated by non‐RT1 genes of BN origin. No strong gender differences in anti‐RII autoimmune responses were observed.</jats:p><jats:p><jats:italic>Conclusion.</jats:italic> Arthritogenic, autoimmune reactivity to homologous RII is under strict genetic control but occurs readily in RT1<jats:sup>av1</jats:sup> rats.</jats:p>