Cell-mediated and humoral immune responses to cartilage antigenic components.

Cell-mediated immunity and antibody production to cartilage antigens were studied in rabbits. From day 3 of immunization an inhibition of leucocyte migration was observed in animals immunized with collagen-free fractions of bovine nasal or human rib cartilage. Delayed cutaneous hypersensitivity was elicited between 5 and 6 days and the circulating antibodies were demonstrated by passive haemagglutination on day 9. No significant correlation was observed between the antibody production and the cell-mediated immunity. Cell-mediated immune responses to cartilage antigens and to purified protein derivative were distinctly different, but the two antigens influenced one another when they were administered together. The 'species common' antigen of connective tissues may be primarily responsible for the early immune reactions.