Cellular source of interferon induced in human peripheral blood mononuclear leukocytes by mumps virus or by tumour cells persistently infected with mumps virus.

Human leukocyte interferon (IFN-a) was induced in cultures of human peripheral blood mononuclear leukocytes (PBML) from seropositive healthy donor infected by mumps virus, or by a human lung carcinoma cell line (Pc-10) persistently infected with mumps virus (Pc-10/M-V). Adherent cells (M0), non-T, non-B cells and B cells all produced IFN in response to mumps virus or Pc-10/MpV cells. The non-T, non-B cells co-cultured with Pc-10/MpV cells produced high-titred IFN. However, T cells did not produced any antiviral factors even in the presence of M0. Furthermore, T cells activated with phytohaemagglutinin (PHA-P), concanavalin A or treated with u.v.-irradiated mumps virus, or Pc-10/MpV cells pretreated with mitomycin C did not produce any antiviral factors in response to either mumps virus or Pc-10/MpV cells.