Abstract
The ability of normal canine tonsil cells, and that of humans with chronic tonsillitis, to lyse hetero-erythrocytes in vitro is shown. Heterologous erythrocyte destruction by tonsil cells is markedly increased after immunization of the animal. Tonsil cells of patients with chronic tonsillitis lyse the erythrocytes coated with streptococcus and staphylococcus antigens more actively. An experimental tonsillitis increases the ability of tonsils to lyse erythrocytes. Since cytolytic activity of tonsil cells is not altered by the removal of phagocytes and treatment with antiglobulin serum, one can presume that it is caused by T-lymphocytes.