Inhibition of herpes simplex virus type 1 (HSV-1) plaque enlargement by neutralizing sera.

The inhibitory activity of neutralizing sera on Herpes simplex virus type 1 (HSV-1) plaque enlargement (PE) is easily detected using the S variant of low passage clinical isolates. The same sera show little or no activity on PE of the product of the S variant rapid in vitro conversion, the L variant, and laboratory strains HSV-1 (F) and (MP). No significant difference was found in the inhibitory activity of sera from healthy individuals with no history of recurrence and patients with recurrences