Collagen-induced arthritis in the rat: modification of immune and arthritic responses by free collagen and immune anti-collagen antiserum.

Inbred Wistar strain rats developed a polyarthritic disease when injected intradermally with Freund's incomplete adjuvant (FIA) containing porcine or bovine type II collagen (CII). In contrast, neither allogeneic rat CII nor porcine proteoglycan monomer were arthritogenic, although both were, to some extent, immunogenic. Animals passively transfused with immune serum containing anti-CII antibodies did not develop arthritis and showed greatly reduced anti-CII humoral immune responses (measured by an enzyme-linked immunosorbent assay) when the serum was administered at the time of and subsequent to challenge with arthritogenic porcine CII. Similarly, the intravenous injection of animals sequentially with 100 microgram soluble CII and 1 ml immune anti-CII antiserum, 9 and 8 days respectively before challenge with arthritogenic CII, abrogated the arthritic response and depressed the humoral anti-porcine CII and anti-rat CII antibody titres more than tenfold. It is concluded that the immune status of the recipient rats with respect to CII is crucially important in determining the nature of the immune and arthritic response to CII appropriately administered in FIA.