[T cell-mediated protective effect in cytomegalovirus infected murine astrocytes].

AIM:To explore T cell-mediated restriction of cytomegalovirus (CMV) in murine astrocytes. METHODS:A T cell-astrocyte coculture system was established, in which astrocytes were infected with mouse cytomegalovirus. Proliferation of T cells was observed under inverted microscope and detected after CFSE staining by flow cytometry. ELISA was used to detect the levels of IFN-gamma and TNF-gamma in coculture supernatants. Observation of astrocyte cytopathic effect (CPE) and PCR assay of cytomegalovirus DNA were also performed. RESULTS:After coculture for 3 d, T cells proliferation was observed under inverted microscope, and flow cytometry assay showed (6.68+/-0.61)% T cells had proliferated (P<0.01 compared with uninfected control). The level of IFN-gamma was (22.9+/-3.4) ng/L in coculture supernatants (P<0.05 compared with uninfected control). While levels of TNF-gamma were under 8 ng/L in both cytomegalovirus infected and uninfected groups. After coculture with T cells 31.25%-75% astrocyte CPE was diminished, and -75% cytomegalovirus DNA load was reduced. Cell-free coculture supernatants also exerted suppressive effect on CPE and viral DNA load. However, the antiviral effect of T cells diminished when added to fresh cytomegalovirus infected astrocytes, accompanied with the decreased level of T cells proliferation and IFN-gamma in coculture supernatants, suggesting the inhibition of T cells' function. CONCLUSION:Cytomegalovirus infected astrocytes could stimulate T cells proliferation and activation. Activated T cells had antiviral effect, which was partly mediated by soluble factors. The function of T cells was rapidly inhibited after activation, of which the underlying complicated mechanisms remain unclear and need further study.