The identification of THY-1 as a putative host determinant for HCMV infection in a large set of 54 cell lines, and the subsequent validation by a series of loss-of-function, gain-of-function, and glycoprotein interaction experiments in both malignant and primary cells strongly suggests that THY-1 has an important role in the initial stage of virus infection. This evidence concerns the gene ART4 and viral infectious disease.