CONSTITUTIVE AND VIRUS-INDUCED INTERFERON-PRODUCTION BY PERIPHERAL BROOD LEUKOCYTES

The production of interferon-alpha (IFN-alpha) by normal human periphe ral blood mononuclear cells (PBMNC) was studied using polyclonal antip eptide antibodies designed to react either with all IFN-alpha subtypes or with individual subtypes IFN-alpha 2 or IFN-alpha 4. In this study , we demonstrate the detection of intracellular IFN-alpha in PBMNC usi ng immunofluorescence staining and flow-cytometric analysis. Virtually all cells of the PBMNC population were shown to produce IFN-alpha rea ctive with all three antisera after stimulation with Sendai virus. The immunofluorescence studies also demonstrated that IFN-alpha is produc ed by PBMNC in the absence of known viral stimulation but is not secre ted in detectable levels. Double-labeling with specific monoclonal ant ibodies to T and B lymphocytes confirmed that the entire populations o f these two cell types produce IFN-alpha, both constitutively and afte r virus induction. Polymorphonuclear cells (PMNC) isolated from Ficoll -Paque pellets were also shown to contain intracellular IFN-alpha, bot h before and after virus induction. The finding that all PBMNC produce IFN-alpha constitutively suggests that IFN-alpha may have important r egulatory functions in situations other than during overt viral infect ions.