Interferon alpha2b is the predominant subvariant detected in human genomic DNAs

Chromosomal DNAs isolated from eight individuals from the Slovak population and from lymphoblastoid Namalwa cells were analyzed for the presence of genes coding for three subvariants of human interferon-alpha 2 (IFN-alpha 2), namely a, b, and c. The respective genes are regarded allelic, because they differ in the coding nucleotide sequence only at the position 137 (a:A, b/c:G) and/or at the position 171 (a/b:A, c:G). IFN-alpha 2 sequences in genomes were selectively amplified using polymerase chain reaction (PCR). Resulting "consensus" PCR-product (the total mixture of PCR-derived clones) was sequenced and the subvariant-specific nucleotides at position 137 and 171 were determined. In one placental genomic DNA and in a mixture of genomic DNAs from leukocytes of seven donors only nucleotides specific for subvariant IFN-alpha 2b could be detected. This suggests that the placental DNA contained only genes coding for IFN-alpha 2b and these alleles were at least prevailing in donor's genomes. On the other hand, the majority of genomic alpha 2-sequences in Namalwa cells (from which IFN-alpha 2c was originally derived), seems to be corresponding to subvariant IFN-alpha 2c.