HSV-2 replication sites, monocyte and lymphocytic cell infection and virion phagocytosis by neutrophils, in vesicular lesions on penile skin. Electronoptical studies of a biopsy.

From a heterosexual male with recurrent genital herpes simplex virus (HSV-2) infection, a fresh intraepidermal vesicle on the penile skin was excised by punch biopsy, fixed and processed for electron microscopy. Differing locations and appearances of capsids and virions were studied to elucidate true host or destroyer cells. HSV-2 propagation and virion formation occurred predominantly in multi- or mononucleate spinosum cells situated at the base of the vesicle. However, some of the monocytes, young histiocytes and lymphocytic cells floating in the vesicle fluid were also involved. They harbored a small number of intranuclear capsids, designating the cells as viral (capsid) carriers. Infrequently encountered free virions in the vesicle fluid were invariably seen near neutrophils. All neutrophil granulocytes examined lacked intranuclear capsids. In contrast, distinct evidence of phagocytosis of virions and some capsids by neutrophils was found in the vesicle fluid near apical portions of spinosum cells packed with virions, or in neutrophils located between virion-loaded spinosum cells in the base lining of the vesicle. In the cytoplasm of neutrophils, single and lysosome-enclosed clusters of virions were noted. Myelin figures and vacuolation of lysosomes in free-floating neutrophils were suggestive of virion distintegration. Viral propagation and abundant virion formation, beside neutrophil and lymphocyte attack, eventually lead to spinosum cell destruction. The minimal cytopathic effects (CPE) observed in involved monocytes and lymphocytic cells floating in the vesicle fluid suggest that these cells might function as vehicles for HSV-2 (capsid) transport to the exterior or interior.