The structural basis of cell-mediated immunological reactions of collagen. Recognition by the cutaneous delayed hypersensitivity reaction in guinea-pigs of conformational alterations of rat and calf skin collagen.

Guinea-pigs were sensitized for delayed cutaneous hypersensitivity reactions to native and thermally denatured rat and calf skin collagens. Native and denatured collagens sensitized the animals to a comparable degree. However, the immune mechanism of the animals differentiated the purely conformational alterations of the molecule, even across the species barrier. Denaturation was accompanied by loss of immunogenic information as well as by exposure of new determinants, not recognizable in the native molecule. The sera of these animals were examined for the presence of antibodies reactive with native collagen in a passive haemagglutination system. Low levels of such antibodies were found in animals sensitized with native collagen and no antibodies reactive with native collagen in animals sensitized with denatured molecules although the latter group of guinea-pigs responded well with delayed skin reactions to native collagen.