A novel class of human type I interferons

The screening of a cDNA library prepared from mRNA of Sendai virus induced Namalwa (human Burkitt's lymphoma) cells, using a human IFN-alpha 2 DNA probe under conditions of low stringency, identified two weakly hybridizing clones containing sequences related to, but discernably different from those of the IFN-alpha class. Sequence and hybridization analysis of these cDNAs as well as expression in E. coli provided evidence that they encode proteins which have the characteristics of IFN type I but which are sufficiently diverged in sequence from both IFN-alpha s and IFN-beta to suggest that they are representatives of a new and distinct class of interferons named interferon-omega. Hybridization of these sequences to genomic DNA reveals that this class contains at least four members.