RESUMEN
<p><b>OBJECTIVE</b>To study the relationship between late mRNA and the cytopathic effect(CPE) and ultrastructural features after human cytomegalovirus (HCMV) infection in vitro.</p><p><b>METHODS</b>Human embryo fibroblast cells(HEL) were infected with HCMV AD169 strain. The expression of the HCMV late mRNA was measured by semiquantitative RT-PCR, the cytopathic effect (CPE) and the cell ultrastructure were observed by means of light microscopy and electron microscopy, respectively.</p><p><b>RESULTS</b>The HCMV late mRNA could be detected 12 hours postinfection and increased gradually, but the CPE appeared 48 hours postinfection in HEL cells. The HCMV infected cells exhibited significant mitochondrial enlargement and the number of mitochondrial ridge deletion, the cisternae lumen of endoplasmic reticulum (ER) dilation and vacuolization (at the end age). The mature nucleocapsid could be observed 96 hours postinfection.</p><p><b>CONCLUSION</b>The ultrastructural changes have an intimate correlation with the expression of HCMV late mRNA and play an important role in the life circle of the virus. HCMV late mRNA may serve as a indicator of the clinical effect of treatment in active HCMV infection.</p>