Abstract
Antiserum specific for hamster thymus-derived lymphocytes, prepared by immunizing rabbits with hamster brain tissue, was cytotoxic to hamster thymocytes > lymph node cells > spleen cells, while virtually non-reactive against bone marrow. This antiserum inhibited spleen cell response to the T cell mitogen, phytohemagglutinin, but not to lipopolysaccharide, a B cell mitogen.