Depressed lymphocyte function after measles-mumps-rubella vaccination.

Healthy children receiving routine measles-mumps-rubella vaccine developed an impaired in vitro lymphocyte response to stimulation with antigen (Candida) but not with mitogen (phytohemagglutinin and pokeweed mitogen). Response of lymphocytes was determined by measurement of the amount of [14C]thymidine incorporated by the cells. The impaired response to antigen lasted from one to five weeks after vaccination. There was no alteration in the number of either total or thymus-derived lymphocytes in the peripheral blood after vaccination; These results suggest that viral vaccination causes a depression of lymphocyte function rather than a depletion of functional lymphocytes.