A soluble protein fraction has been isolated from the cornea by simple aqueous extraction. This preparation possesses transplantation antigen activity as demonstrated by its ability to induce a specific sensitization resulting in the accelerated destruction of a corneal graft. The corneal antigen preparation is also capable of stimulating the production of humoral antibodies, but the relationship between the transplantation immunity and the antibody response remains to be elaborated.
Leibowitz HM, Luzzio AJ. Transplantation Antigens in KeratoplastyI. Isolation of a Soluble Fraction With Transplantation Antigen Activity. Arch Ophthalmol. 1970;83(2):215–222. doi:10.1001/archopht.1970.00990030217016