TUMOUR NODULE FORMATION AS AN IN VIVO MEASURE OF SUPPRESSION OF CELLULAR IMMUNE RESPONSE BY ANTILYMPHOCYTIC SERUM

THE ability of antilymphocytic serum (ALS) to suppress cellular immunity1, delayed hypersensitivity2,3 and humoral antibody responses4,5 has been known for some time. Although only the primary humoral antibody response is suppressed it has been shown that ALS effectively suppresses the immune response to both first and second set skin grafts6. The first practical application of ALS was to prolong graft survival, but recently there have been reports of the enhancement of virus pathogenicity7, emergence of latent virus strains and enhanced oncogenicity of tumour viruses in vivo in animals treated with ALS8. It is therefore apparent that ALS may become important in the study of pathogenic agents. © 1969 Nature Publishing Group.