Induction and Ly phenotype of suppressor T cells in mice during primary infection with dengue virus

Infection of mice with dengue-4 virus produced a significant, transient immunosuppression of the delayed-type hypersensitivity (DTH) response to sheep red blood cells (SRBC). Suppression was noted on day 3 after infection, was maximal on day 5 and was no longer evident on day 13 after infection. The suppressive effect was transferable to normal mice by viable spleen cells from immune mice but not by immune serum. These cells appeared to be present in the spleens of infected mice as early as day 1 after infection and were still detectable on day 7. No evidence was obtained that suppression was mediated by a soluble factor. Further characterization of the cells which could transfer suppression showed them to be T cells possessing both Ly-1 and Ly-2 surface antigens. These data suggest that there may exist two types of T suppressor cells or that, alternatively, an interaction between Ly-1+ and Ly-2+ cells was required to produce suppression. The significance and implications of these findings are discussed.