Conditions required for induction of murine p30 by herpes simplex virus

Abstract
Mouse cells (line N clA cl10) contain 1.2–2.5 ng murine leukaemia virus (MuLV) p30 antigen/mg of protein; this amount of antigen is measurable by competition radioimmunoassay (RIA) but is not detectable by indirect immunofluorescence (IF). Infection of N clA cl10 cells with herpes simplex virus type 2 (HSV‐2) induces expression of MuLV p30. Induction by HSV‐2 does not require either cell or virus DNA synthesis and is optimal 8 h post infection when cells at 50–70% confluence are infected at a multiplicity of infection (MOI) of 5–8 PFU/cell. At an MOI of 2.5, 70–80% of the cells express HSV antigens while none of the cells express p30; at an MOI of 5.0, 70–80% of the cells express HSV antigens but 55% of the cells express p30. Using the conditions reported in this paper for preparation of competing antigen, induction of p30 by HSV‐2 (strain 333) infection is not measurable by competition RIA.