The suppressive effect of halothane on DNA synthesis of immunocytes.

Mice, previously immunized with sheep erythrocytes, were anaesthetized with halothane and the splenic lymphoid cells were incubated with 3H-thymidine at 1-h intervals. Abiphasic response was observed; 0.9 and 1.5% halothane reduced 3H-thymidine incorporation into the primed lymphoid cells by 83 and 94% respectively, while 0.4% halothane stimulated it by 5% of control at 3H. Immunosuppression by halothane may be the result of reduced 3H-thymidine uptake of the dividing immunocytes.