[A study of acute infection of herpes simplex virus in mouse trigeminal ganglia]

We investigated the shift to latency and protective reaction in mice trigeminal ganglia after inoculation of herpes simplex virus type 1 (HSV-1) onto the cornea. BALB/c mice were inoculated and the trigeminal ganglia were removed periodically. Lymphocytes in the ganglia were observed using immunocytochemical techniques. The results obtained were as follows: (1) HSV-1 positive neuronal cells were recognized at 3 days after inoculation but not at 14 days. (2) The relative proportion of T cells in lymphocytes was greater than that of B cells at 3 days, but B cells were more numerous at 5 days. Then T cells become more numerous again at 7 days. (3) Among the subsets in T cells, the ratio of CD4+ and CD8+ cells was almost equal at 3 days, but then CD4+ cells increased and CD8+ cells had disappeared at 14 days after inoculation. These results show that HSV-1 that reached the trigeminal ganglion from the cornea by axonal transport infected neuronal cells, multiplied there and then disappeared resulting in latency. Cellular immunity, especially the function of CD4+ cells, played a main role in this protective reaction by suppressing the viral growth.