Comparative Susceptibility of Neonatal Rabbit Skin to Herpes Simplex Virus in vitro . ∗

Summary

The remarkable susceptibility of the mammalian neonate to some viral infections raises the issue of the relative importance of humoral immunity, delayed hypersensitivity, and the intrinsic resistance of cells and tissues of the host. The present studies focused on the tissue of the host and involved the interaction in vitro of herpes simplex virus with preparations of skin fragments from newborn and more mature rabbits. The cutaneous tissue from 1-2-day-old rabbits consistently synthesized 3-10-fold more virus than tissue from 1-2-month-old rabbits. Studies indicated no apparent difference in the attachment of virus to immature and mature rabbit skin. Interferon-like-substance was elaborated in equivalent, low titers by cutaneous tissue from newborn and adult rabbits. Light and electron microscopic study of rabbit skin failed to discern apparent differences in the population, morphology, or lysosomal content of cutaneous tissue. Virus-free preparations of 2-day-old rabbit skin incorporated 100% more thymidine-2-C¹⁴ than skin from 2-month-old rabbits but the incorporation of uridine-2-C¹⁴ by these tissues was essentially equal. Thus, the cutaneous tissue of the newborn rabbit appears particularly well suited biochemically for the synthesis of DNA-containing-herpes simplex virus.