Horse anti-bovine lymphocyte serum. Its effect in calves.

Anti-bovine lymphocyte serum (ABLS) had been prepared in horses with calf thymocytes as antigen and its effects in calves following parenteral administration were studied. The optimal dose was found to be one ml/kg body weight. The ABLS suppressed both the T and B cell functions. The former was indicated by the disturbed response to sheep erythrocytes infections, by the decreased number of spontaneous E rosette forming lymphocytes, the prolonged survival of skin allografts and the significant inhibition of the delayed hypersensibility skin reaction (tuberculination) following administration of Mycobacterium microti. The latter was based on the disturbed response to a subcutaneous dose of tetanus toxoid. The reaction of lymphocytes of ABLS treated calves to phytohemagglutinin and poke week mitogen was also inhibited. The disturbed reactions of the T and B cells might be among others based on the strong reduction of lymphocytes in the blood circulation by ABLS (up to 10-20%).