It has been demonstrated that there are normally occurring antibodies to gelatin in human sera. Immunization with gelatin can in many cases increase the antibody level. The presence of these antibodies does not result in cutaneous reactions of the wheal and erythema type after injection of antigen.
Many of the properties of the gelatin-antigelatin reaction and the precipitates formed are those of a truly specific antigen-antibody aggregate.
Explanations have been advanced both as to the possible sources of the gelatin antibody and its significance.