Stuart, J.

Abstract Chick type II collagen (CII), a protein commonly found in joint cartilage, induces an autoimmune arthritis when administered to susceptible strains of mice. A cyanogen bromide fragment of CII, CB11, contains the requisite epitopes critical for inducing collagen-induced arthritis. If administered as a tolerogen, however, before immunization, CB11 prevents the onset of disease. Therefore, delineation of structural elements of CB11 that can regulate autoreactive T cells became the goal of this study. To delineate the structural elements of CB11 antigenic to T cells, 14 peptides containing overlapping sequences of CB11 were generated. Mononuclear cells from CII-immunized DBA/1 mice were cultured with these peptides and the resulting supernatants examined for the production of IFN-gamma. Two peptides, CII 181-209 and CII 245-270, generated the greatest responses. The ability of these two peptides to regulate arthritis was tested by administering them to neonatal DBA/1 mice as tolerogens before immunization with CII. Both peptides suppressed the incidence of arthritis whereas no other peptide used as a tolerogen significantly altered the course of the disease. T cells from four arthritis-resistant murine strains did not recognize either peptide when immunized with CII, whereas cells from the disease-susceptible B10.Q mice responded well to both. Thus, the coincidence of T cell responses to CII 181-209 and CII 245-270 in CIA-susceptible mice and the lack of response in disease-resistant strains or CII-tolerized mice identify these two peptides as containing important T cell epitopes that regulate CIA.

Abstract Type II collagen from six mammalian species was investigated for the capacity to induce an immune response and collagen-induced arthritis (CIA) in C57/B10 congenic mouse strains. H-2q haplotype mice were susceptible to chick, bovine, deer, rat, and human type II collagen, but were resistant to arthritis induced by porcine type II collagen. H-2r haplotype mice only developed CIA in response to bovine, deer, and porcine collagen. High antibody responses in the absence of disease, directed against a specific type II collagen, were observed in many independent haplotypes. The cross-reactive capacity of different antisera to the various collagen species was studied. The data support the existence of two arthritogenic and multiple nonarthritogenic epitopes on the type II collagen molecule.

Abstract Pretreatment of mice genetically susceptible to type II collagen-induced arthritis (CIA) with monoclonal or polyclonal antisera specific for I region gene products (Ia antigens) suppressed or delayed the onset of CIA, whereas pretreatment with anti-Ia to an irrelevant haplotype was without effect. The humoral response to type II collagen was transiently depressed 14 days after immunization but antibody levels did not differ significantly after 28 days. The peak delayed-type hypersensitivity to type II collagen was unaffected by anti-Ia treatment. Monoclonal antibody of one anti-Ia specificity enhanced both the antibody response and the arthritis incidence in one mouse strain.

Arthritis was induced by immunization of type II collagen in adjuvant in mice from H-2q-bearing crosses between SWR (H-2q/q) and B10 (H-2b/b mice), two strains known to be resistant to collagen-induced arthritis (CIA). The resistance of B10 is known to be due to its MHC haplotype, but it was postulated that the resistance of SWR mice which expresses the susceptible MHC haplotype could be due to the deletion of close to 50% of the V beta genes of the T cell receptor (TCR) in them. 17% of the F1 hybrids, 33% of the SWR backcrosses, 68% of the B10 backcrosses, and 52% of the F2 hybrids developed arthritis on follow-up to 5 mo after primary immunization with collagen. There was no significant difference in anti-type II collagen antibody titers between the arthritic and nonarthritic mice in each of these crosses. The segregation of the TCR genes with arthritis was determined in the F2 population by typing with F23.1 mAb that reacts with T cells using V beta 8 subfamily genes in their TCRs. SWR mice are F23.1- as V beta 8 genes are deleted in them. All six of arthritic mice homozygous for H-2q, and thus with an H-2 haplotype similar to SWR mice, expressed the F23.1 marker. These studies indicate that for complete susceptibility to collagen-induced arthritis, not only is a susceptible MHC haplotype (H-2q) important, but possibly also the presence of a subset of T cells using certain specific V beta genes in their TCRs. Other background genes may, however, modulate the severity of arthritis.