[The persistence of the distemper virus in continuous human cells].

Two cultures chronically infected with distemper virus (HEP-2 and L-41) were obtained. The cultures produced a small-plaque cell-associated virus and a virus-specific antigen which was demonstrated by the fluorescence antibody technique in 40%-60% of the cells. The chronically infected cells produced interferon as judged by their resistance to superinfections with heterologous viruses.