Depressed 3H-thymidine incorporation by measles infected mononuclear cells can be corrected by treatment with isoprinosine or 5-fluoro-2-deoxyuridine.

Incorporation of thymidine by measles infected PHA-activated lymphocytes was found to be depressed although production of interleukin 2 (IL-2) and expression of IL-2 receptors on these cells was similar to that of non-infected cells. The decrease in incorporation of 3H-thymidine by infected cells was not due to cell death and could be restored by treating the cells with isoprinosine or 5-fluoro-2-deoxyuridine. These results suggest that the depressed incorporation of 3H-thymidine by measles-infected cells is not due to inhibition of early events required for lymphocyte proliferation, but is rather due to interference in the thymidine pathway required for the synthesis of DNA.