Herpes simplex virus encephalitis in suckling mice: ultrastructural studies of virus replication

Ultrastructural studies concerning the replication and release of a neuro-adapted strain of herpes simplex virus were carried out on acutely encephalitic mice. It was found that envelopment of nucleocapsid particles at the nuclear membrane of brain cells was inefficient, resulting in accumulation of unenveloped nucleocapsids in the cell cytoplasm. These nucleocapsids were associated with arrays of microtubules within cytoplasmic processes. Enveloped particles were rarely present in tissur spaces. Those that were seen appeared to be in a state of disintegration. This replication process of herpes simplex virus in the murine encephalitis model differs from that observed in tissue culture cells. The implications of these differences are discussed.