Antibodies to type II and XI collagens: Evidence for the formation of antigen specific as well as cross reacting antibodies in patients with rheumatoid arthritis

Abstract

Antigen specific and cross reacting antibodies to native and denatured types II and XI collagen were detected in the sera of rats immunised with either of these antigens. The antibodies from rats immunised with type XI collagen initially showed the strongest binding to the α2(XI) chain of type XI collagen but later binding to the α3(XI) chain was seen. Sera from patients with rheumatoid arthritis had antibodies that bound to both type II and XI collagens. Immunoblotting studies showed that most patients had antibodies which bound to the α1(II) chain of type II collagen and to the α3(XI) chain of type XI collagen. Some patients also had antibodies which bound to the α1(XI) and to the α2(XI) chains of type XI collagen. Thus antibodies to unique as well as to common epitopes on each of the two types of collagen molecule occur in some patients with rheumatoid arthritis.