[Cytotoxic antibodies against lymphocytic antigens of cattle]

Typing reagents for the identification of bovine lymphocyte antigens were prepared. Sera obtained from cows killed in slaughterhouse were a good source of cytotoxic antibodies. Out of the 300 sera tested, 98 were cytotoxically active. The selected sera with a low reaction frequency were tested on a panel of 132 non-related animals. On the basis of the correlations between the sera, thirty of them could be included in four clusters. The sera within each cluster were closely associated; hence it can be assumed that a distinct specificity is represented by each of the clusters. It is suggested by correlation analysis and by the distribution of antigens in the population under study that the determined antigens fall within the same system and are genetically controlled by one or several closely associated loci.