Interferon-α8b the Only Variant of Interferon-α8 Identified in a Large Human Population

Three variants of human interferon (IFN)-α8 gene, that is, IFN-α8a, IFN-α8b, and IFN-α8c, have been reported previously. They differ from each other by changes in their coding region at nucleotide positions 359360, 372, and 550. Human genomic DNA obtained from over 28,000 healthy blood donors and from 4 human cell lines was used in the polymerase chain reaction (PCR) designed for specific amplification of the IFN-α8 gene fragments. The resulting PCR product was analyzed by (1) restriction endonuclease digestion, (2) DNA sequencing, and (3) allele-specific secondary PCR amplification. Only one sequence for IFN-α8 was identified, and that was for IFN-α8b. The sequences for IFN-α8a and IFN-α8c were not detected after PCR amplification either in the pooled leukocytes obtained from > 28,000 individuals or in cell lines tested. These data suggest that the naturally occurring variant or allele for IFN-α8 in the population is IFN-α8b. IFN-α8a and IFN-α8c variants were consistently below the level of detection of the assays and, if present at all in the population, are very rare.