It is noteworthy that immunisation with the two peptides (hGPI325–339 plus hGPI544–558) induced significantly higher titres of anti-mouse GPI antibodies than that with hGPI325–339 alone, whereas the severity and incidence of arthritis in mice immunised with two peptides (hGPI325–339 plus hGPI544–558) were comparable with those in mice immunised with hGPI325–339 alone (Figures 3a and 6a). The gene discussed is GPI; the disease is arthritic joint disease.