Acquired resistance to type II collagen-induced arthritis in rhesus monkeys is reflected by a T cell low-responsiveness to the antigen.

Ten out of 14 rhesus monkeys developed arthritis after a single immunization with bovine type II collagen (B-CII). In contrast to primary resistant monkeys, arthritic animals showed a B-CII specific T cell proliferation during the induction phase of the disease. All surviving animals showed a full remission of the disease. Two monkeys acquired resistance to collagen-induced arthritis (CIA) after one period of disease, but in three animals a booster immunization with B-CII induced a slight flare-up. It is demonstrated that B-CII immunized rhesus monkeys have the capacity to restore resistance to CIA. The development of resistance to CIA is reflected by a decreased T cell responsiveness to B-CII. It is shown that the lack of IL-2 plays a role in B-CII-induced T cell low-responsiveness. A potential role of CD8+ T cells in the down regulation of the T cell response to B-CII is discussed.