Tumor-Associated Immunity in Bovine Ocular Squamous Cell Carcinoma Detected by Leukocyte Adherence Inhibition Microassay

A microplate modification of the leukocyte adherence inhibition (LAI) assay was used with blood leukocytes from cattle with ocular squamous cell carcinomas (OSCC); control groups were cattle with ocular or cutaneous lesions (not carcinoma) and healthy normal cattle. For the assay, saline extracts of OSCC and skin from the same donor, lymphosarcoma, and mastocytoma (M) were used as antigens. Specific LAI reactivity to OSCC extract (but not to skin extract) was detected in 14 of 18 animals with squamous cell carcinoma. One animal with OSCC showed LAI reactivity to both OSCC and M-extracts. No control animals had LAI reactivity to OSCC extract, but 1 clinically normal cow had LAI with the M-extract. Leukocyte adherence stimulation reactions with the various antigens were seen in all groups of animals.