Acute and persistent varicella-zoster virus infection of human and murine neuroblastoma cell lines

Human and murine neuroblastoma cell lines were infected in vitro with varicella-zoster virus (VZV). Infected human neuroblastoma cells (IMR-32) supported the synthesis of abundant viral antigens as detected by indirect immunoperoxidase labeling using human serum rich in anti-VZV antibodies and did not survive the infection. In situ hybridization (ISH) with VZV-cloned probes revealed a strong hybridization signal in these infected cells. During cultivation, the virus was released in the culture medium, and viral polypeptides were revealed by Western blotting of infected cells, using either a monoclonal anti-gpI antibody or a rabbit antiserum. All these findings indicate that IMR-32 cells support a productive and lytic infection by VZV, whether infected by cell-free virus or by cocultivation with infected cells. Murine neuroblastoma cells (neuro-2A) survived VZV infection and did not produce any infectious virus. No VZV-specific proteins were detected in infected cells either by immunolabeling or by Western blotting. However, viral nucleic acids could be detected by ISH, indicating that mouse neuroblastoma cells displayed a nonproductive, nonlytic infection. Infected neuro-2A cells have been examined by ISH using probes corresponding to immediate early (IE) genes 4, 62, and 63 and late (L) gene 31 encoding gpII. A strong hybridization signal was detected when infected cells were probed with a fragment containing the IE genes 62 and 63. Lower levels of hybridization were detected with the other probes, corresponding to IE or L genes. These systems allow comparative molecular analysis of persistent and acute infection of nerve cells by VZV.