Human cytomegalovirus infection in a retinoblastoma cell line in vitro

Background: The focus of these studies was to determine whether the Y79 hum an retinoblastoma cell line could function as a good in vitro model system for studying human cytomegalovirus (HCMV) infection. Methods: Y79 cells wer e exposed to an HCMV mutant carrying a LacZ gene, and the resulting beta-ga lactosidase expression in infected cells was assessed by flow cytometry. Th e extent to which the three classes of viral gene products - immediate earl y, early, and late proteins - were expressed was analyzed by immunohistoche mical staining and Western blotting. Infected Y79 cells were also co-cultiv ated on human foreskin fibroblast (SF cell) cultures to recover virus. Resu lts: Infection of Y79 cells with the virus resulted in beta-galactosidase e xpression as detected by flow-cytometric analysis. Immunohistochemical stai ning revealed that a portion of Y79 cells expressed antigens reactive to mo noclonal antibodies against immediate early, early, and late HCMV proteins. The 43-kDa early gene product was also detected by Western blotting. Infec ted Y79 cells co-cultivated on SF cell cultures yielded infectious foci, wh ich turned blue following X-gal staining, demonstrating productive HCMV inf ection in the Y79 cells. Conclusion: These results demonstrate that while H CMV can productively infect Y79 cultures, it does so in a highly inefficien t manner, leading these authors to conclude that this cell line does not pr ovide a particularly good model system to study HCMV infection.