Persistent infection of a human lymphocyte cell line (Molt-4) with the kilham rat virus.

Inoculation of a human thymus-derived lymphocyte cell line (Molt-4) with the Kilham rat virus resulted in persistently infected cultures, that released infectious virus for periods up to seven months. At any time following infection, a small percentage of the cells were positive for rat virus antigens as determined by immunofluorescene assay.