Natural killer cytotoxicity and antibody-dependent cell cytotoxicity to herpes simplex virus-infected target cells in murine pregnancy.

In vitro natural killer cytotoxicity (NKC) and antibody-dependent cell cytotoxicity (ADCC) activity against herpes simplex virus (HSV)-infected cells were evaluated in a pregnant murine model (C57Bl6 inbred strain). Virgin (n = 16) and pregnant (late gestation) mice (n = 15) were infected intraperitoneally with HSV, type 1. After 18 hr, a 0.5-ml aliquot of the peritoneal wash was frozen for virus plaque assay, and the cells were cultured in the 51chromium release assay for NKC and ADCC. %NKC (mean +/- S.E.) to HSV-infected targets was significantly suppressed (P less than 0.05) in pregnant mice, 10.3% +/- 1.9, compared to that of virgin mice, 32.5% +/- 2.5. This suppression was abrogated with HSV-specific antisera (%ADCC); 53.9% +/- 4.4 (pregnant) compared to 49.1% +/- 3.6 (virgin). The diminished NKC activity in pregnant mice was reflected in an increased mean number of virus particles in the peritoneal wash, 266 +/- 66 PFU/ml, compared to 38 +/- 11 PFU/ml in virgin mice (P less than 0.05). We concluded that NKC, but not ADCC, to HSV-infected targets was suppressed and that HSV elimination was impaired in pregnant mice.