“…Many investigators have reported that cellular differentiation by the addition of chemicals or cytokines such as phorbol esters, DMSO, retinoic acid, hydrocortisone, concanavalin A, dimethylacetimide, sodium valproate, β-gonadotropin, nerve growth factor or dbcAMP is necessary to induce permissive CMV infection or to increase CMV gene expression and virus replication in primary cells and cell lines (Dutko & Oldstone, 1981 ;Tanaka et al, 1985Tanaka et al, , 1991La Femina & Hayward, 1986 ;Weinshenker et al, 1988 ;Forbes et al, 1990 ;Ibanez et al, 1991 ;Turtinen & Seufzer, 1994 ;Kuntz-Simon & Obert, 1995). Here, we report that pretreatment of the oligodendrocyte cell line HOG with either PMA or dbcAMP\IBMX permitted infection with CMV as judged by the expression of the early and late CMV genes and release of extracellular infectious CMV particles.…”