Another glycoprotein complex unique to HCMV is a pentameric complex consisting of gH/gL combined with products of the UL129-131A open reading frames, gH/gL/UL129-131A, that has been shown to be required for efficient infection of myeloid cells, endothelial cells, and epithelial cells but dispensable for infection of fibroblasts (3, 6, –, 10). Here, ART4 is linked to infection.