Oral administration of type-II collagen peptide 250--270 suppresses specific cellular and humoral immune response in collagen-induced arthritis

Oral antigen is an attractive approach for the treatment of autoimmune and inflammatory diseases. Establishment of immune markers and methods in evaluating the effects of antigen-specific cellular and humoral immune responses will help the application of oral tolerance in the treatment of human diseases. The present article observed the effects of chicken collagen II (CII), the recombinant polymerized human collagen II 250—270 (rhCII 250— 270) peptide and synthesized human CII 250—270 (syCII 250—270) peptide on the induction of antigen-specific autoimmune response in rheumatoid arthritis (RA) peripheral blood mononu- clear cells (PBMC) and on the specific cellular and humoral immune response in collagen- induced arthritis (CIA) and mice fed with CII (250—270) prior to immunization with CII. In the study, proliferation, activation and intracellular cytokine production of antigen-specific T lymphocytes were simultaneously analyzed by bromodeoxyuridine (BrdU) incorporation and flow cytometry at the single-cell level. The antigen-specific antibody and antibody-forming cells were detected by ELISA and ELISPOT, respectively. CII (250—270) was found to have stimulated the response of specific lymphocytes in PBMC from RA patients, including the increase expression of surface activation antigen marker CD69 and CD25, and DNA synthesis.