Dose-dependent inhibition of virus rescue from lymphocytes latently infected with turkey herpesvirus or Marek's disease virus.
The number of plaque-forming units (PFU) of turkey herpesvirus (HVT) isolated per 10(6) latently infected splenic lymphocytes was determined by co-cultivation on permissive monolayer cultures in 35-mm-diameter Petri dishes. Doses of 1 x 10(6) spleen cells or less per culture gave uniform dose-related titers, whereas doses of 8 x 10(6) cells often yielded less than 1-2% of the expected number of PFU. Intermediate doses gave proportionally reduced virus yields. This dose-dependent inhibition was observed with spleen cells from birds within a week after infection and became more marked with time. A similar phenomenon occurred with a non-oncogenic Marek's disease virus (MDV) isolate (SB-1) but not with oncogenic MDV isolates (CU-2, JM-10, GA-5), except in genetically resistant birds. High numbers of uninfected spleen cells mixed with low numbers of HVT-infected cells during assay reduced titers only slightly. Immunosuppression by combined neonatal thymectomy and cyclophosphamide treatment before HVT infection prevented the inhibition, but embryonal bursectomy had no effect.
D000818:Animals; D002478:Cells, Cultured; D002642:Chick Embryo; D002645:Chickens; D005347:Fibroblasts / Q000382:microbiology; D006564:Herpesviridae / Q000276:immunology*; D008381:Herpesvirus 2, Gallid / Q000276:immunology*; D008214:Lymphocytes / Q000382:microbiology*; D013154:Spleen / Q000276:immunology / Q000382:microbiology; D010948:Viral Plaque Assay / Q000662:veterinary