Objective:To study neural cell tropism of human herpesvirus 6A(HHV-6A) and its effect on neural cell cycle. Methods:The cell morphology was assessed by a light microscope. The fragment of HHV-6A U22 gene was amplified by PCR and relative amount of HHV-6A U22 gene was analyzed using quantitative real-time PCR. Expression of HHV-6A gB was examined by immunocytochemical and Western blot analysis. Cell proliferation was measured by MTT assay. Cell cycle analysis was evaluated by the propidium iodide assay. Results:On the fifth day after being infected by HHV-6A,U373 cells had no obvious change,but SK-N-SH and SHG44 cells showed cytopathic effect. HHV-6A U22 gene was detected in all three infected cell lines and its relative amounts kept reducing all the time. HHV-6A gB was positive in the three infected cell lines,furthermore, the expression levels in U373 and SHG44 were more than those in SK-N-SH. HHV-6A stimulated the proliferations of U373 and SHG44 cells,however,inhibited the proliferation of SK-N-SH cells significantly. Compared with uninfected cells,percentages of U373 and SGH44 cells were decreased in phase G1 but increased in phase S and G2 after cells were infected by HHV-6A,as to SK-N-SH,the percentages were increased in phase G1 but decreased in S and G2 phases. Conclusion:All three neural cell lines can sustain replication of HHV-6A,and moreover,HHV-6A can boost astrocyte proliferation and inhibit neuronal cell proliferation.