Characterization of blood mononuclear cells producing IFN alpha following induction by coronavirus-infected cells (porcine transmissible gastroenteritis virus)

Porcine blood mononuclear cells (PBMC) were shown to produce interferon-alpha (IFN alpha) following incubation with cells infected by a coronavirus, transmissible gastroenteritis virus. Monoclonal antibodies (mAb) with specificities for leukocyte subsets and major histocompatibility complex (MHC) antigens were used to characterize IFN alpha producer cells. The production of IFN alpha was found to be a function of non-phagocytic, non-adherent, non-T, non-B, CD4+ (and to a lesser extent CD8+) MHC-class-II-positive cells. Furthermore, addition of anti-MHC (class II) mAb during PBMC incubation with virus-infected cells reduced IFN yields, suggesting that masking of these surface antigens alters PBMC responsiveness to IFN induction.