Expression patterns of Human Interferon-alpha and Interferon-lambda subtypes by monocytes, dendritic cells and B cells. (136.14)

Abstract Human interferon-alpha comprises a family of thirteen highly homologous genes and twelve subtypes (coding sequences of IFN-alpha1 and -13 are identical). We employed two modifications of fluorescent-labeled probe technology--molecular beacons (MB) and locked-nucleic acids (LNA) to develop a highly efficient, sensitive, and specific quantitative RT-PCR assay for each human IFN-alpha subtype as well as the three subtypes of IFN-lambda, and for completion, IFN-beta and -gamma. The assay is formatted to a 384-well plate that measures 16 samples/plate and includes four-point standards for each IFN. Using this assay, we determined expression patterns of these IFN by monocytes, monocyte-derived macrophages and dendritic cells (MDM and MDDC), primary mDC, pDC and B cells in response to ligands for TLR 3, 4, and 9. All the myeloid cells, including mDC expressed high levels of IFN-beta and -lambda1, and moderate levels of IFN-alpha. pDC expressed high levels of almost all IFN, although with quantitative and in one case, a qualitative difference in between the response to CpG (TLR9) vs. imiquod (TLR7). B cells also expressed IFN—more subtypes than myeloid cells, but and fewer than pDC. Type I IFN expression was always accompanied by type III IFN expression. We conclude that IFN expression patterns are both ligand and cell-type specific. Subtypes alone or in combination may have unique roles in the innate immune response.