Interferon lambda-1 (IFN-lambda1/IL-29) induces ELR(-) CXC chemokine mRNA in human peripheral blood mononuclear cells, in an IFN-gamma-independent manner

Interferon lambda-1 (IFN-lambda1), the prototype Type-III interferon, has antiviral functions similar to those of the Type-I interferons, IFN-alpha and IFN-beta. However, IFN-lambda1 is capable of signaling through almost all STAT molecules and so it is possible that it may have novel immunoregulatory functions in addition to antiviral ones. From a range of chemokines tested, IFN-lambda1 elevated mRNA levels of only 'Monokine induced by IFN-gamma' (MIG/CXCL9), 'IFN-gamma inducible protein-10' (IP-10/CXCL10) and 'IFN-gamma inducible T-cell alpha chemoattractant' (I-TAC/CXCL11) from human peripheral blood mononuclear cells. As their names suggest, these chemokines are also induced by IFN-gamma, the only member of the Type-II interferon family. This action of IFN-lambda1 did not depend on intermediate induction of IFN-gamma and is therefore, likely to be independent of IFN-gamma. Further, our results suggest that donors responded to IFN-lambda1 stimulation either 'early' or 'late'. Overall the action of IFN-lambda1 was similar to that previously reported for IFN-gamma and may invite more detailed investigation of the role of IFN-lambda1 at the innate/adaptive interface.