Herpes simplex virus type 1 genes in human mononuclear cells and affecting cell-mediated immunity

To evaluate whether herpes simplex virus type 1 (HSV-1) replicates in freshly isolated human mononuclear cells (HMNC) and results in cell-mediated immunity, HMNC purified from the peripheral blood of a healthy HSV-1-seronegative individual were infected with HSV-1 (KOS strain). The kinetic data indicated that HSV-1 particles were detected in HMNC at 9 hr postinfection, and the highest HSV-1 titer was obtained at 24 hr postinfection. It was found that the newly synthesized HSV-1 DNA increased in HMNC corresponding to the duration of time postinfection. The HSV-1 tk mRNA was detected in HSV-1-infected HMNC by Northern blot analysis. The Western blot analysis indicated that the HSV-1-infected HMNC could express the viral proteins. These results suggest that HSV-1 replicates in freshly isolated HMNC and expresses its DNA, RNA, and proteins. Interleukin-2 (IL-2) production and cell-mediated cytotoxicity (CMC) were also determined in HSV-1-infected HMNC but were lower than those found in uninfected HMNC. On the other hand, HSV-1 DNA was detectable in HMNC of patients suffering from recurrent HSV-1 infection. The results show that, in the recrudescent phase, the patients' HMNC contain more HSV-1 DNA than in the convalescent phase. We conclude that the impairments of immune responses are related to the infection of HMNC by HSV-1.