Ocular antigens VIII: assay of delayed hypersensitivity to corneal epithelium in the rabbit.

Rabbits were sensitised with complete bovine corneal epithelium. The lymphocyte stimulation test was performed with the lymphocytes of these rabbits using the soluble and sonicated insoluble fraction of the corneal epithelium as the antigens. A striking difference existed in the optimal test conditions for these antigen fractions. By comparing the results of the lymphocyte stimulation test with other immunological parameters, namely, skin test reaction, antibody titre, and phytohaemagglutinin stimulation of the lymphocytes, we concluded that both antigen fractions stimulate predominantly the T-lymphocyte system, although boosting augmented the humoral immune response. Stimulation of the cultured lymphocytes by both the separate and mixed antigen fractions is evidence for the existence of crossreacting antigens between the soluble and insoluble epithelial fractions.