EXPRESSION OF IFN A GENES IN SUBPOPULATIONS OF PERIPHERAL-BLOOD CELLS

The polymerase chain reaction (PCR) was used to detect the expression of IPN A genes in general (with 'universal' primers) and specifically the expression of mRNA transcripts encoding the subtypes IFN-alpha-1, -alpha-2, -alpha-4, -alpha-5 and -alpha-14 (with gene specific primers ) in normal human peripheral blood mononuclear cells (PBMC) and PBMC s ubpopulations. Our examination revealed that all transcripts tested fo r could be detected not only following induction with inducers such as Sendai virus, Semliki Forest virus and poly(I):poly(C), but also in t he absence of induction. IFN A1, IFN A2 and IFN A4 mRNAs were found to constitute the major transcripts of Sendai virus and poly(I):poly(C) induced PBMC. Fractionation of PBMC into T cells, B cells, adherent ce lls, mononuclear (MN) cells and polymorphonuclear (PMN) cells revealed that these cell populations an contain specific IFN A mRNA transcript s both in the absence of an inducer and following induction with Senda i virus. The proportion of IFN A transcripts detected was dependent an the cell type investigated. IFN A1, IPN A2 and IFN A4 transcripts con stituted the major RNA species present in PBMC and PMN cells. In MN ce lls IFN A5 transcripts were also present as a major IFN RNA species. E xpression of the IFN A transcripts tested for in T cells, B cells and adherent cells did not vary significantly. These results emphasize the importance of identifying IPN A subtype expression in order to furthe r our understanding of the biological significance of differential reg ulation and expression of particular IFN-alpha subtypes.