Immunotherapy of bovine ocular squamous cell carcinomas.

Squamous cell carcinomas were collected from the eyes of cattle and saline phenol extracts of the tumours were prepared. The aqueous phase of the extract was used in studies on the immunotherapy of ocular squamous cell carcinomas in cattle. After a single intramuscular injection of the extract, regression and sometimes complete disappearance of eye tumours were observed in 39 of 46 carcinomas. Tumours as large as 4 X 5 cm regressed completely. Enhanced growth of tumours was noted in two of three cattle given multiple injections. Regressing tumours were examined histologically and regression appeared to be associated with a cell-mediated immune reaction. Spontaneous regression of a confirmed squamous cell carcinoma was observed in one animal. This spontaneous tumour in one of the larger domestic animals provides a useful experimental model for the study of tumour antigens.