Type I Interferon Dependent Anti-viral Activity

Synthetic oligonucleotides (ODN) expressing CpG motifs trigger an innate immune response via TLR9. Multiple microarray analyses were performed to identify the global effects on gene expression of stimulating the CAL-1 human pDC line with different types of CpG ODN. Results show that a subset of genes characterized by shared anti-viral activity was consistently up-regulated by ODNs that otherwise mediate discrete functions. This group of genes was largely dependant on autocrine type I interferon (IFN) signaling, as their induction was blocked by neutralizing antibody targeting the type I IFN receptor. Coupling these experiments with a meta-analysis of other published works led to the identification of a set of 32 functionally conserved genes that was reproducibly activated by different types of CpG DNA in different species and cell types. Functionally, these 'core' genes support a type I IFN response to viral infection, and differ from genes up-regulated by only a single type of CpG ODN. These findings help define the conserved and sequence-specific patterns of gene activation triggered via TLR9 and improve our understanding of the immunomodulatory effects elicited by CpG ODN. pDC cells were stimulated with either 3uM 'K' ODN for 1-27 hours (1 hr n=3, 3 hr n=3, 9 hr n=5, 27 hr n=3) or with 3uM 'D' ODN for 1-48 hours (1 hr n=3, 3 hr n=3, 9 hr n=3, 27 hr n=5, 48 hr n=3) or with 3uM respective control ODNs: ODN1612 for 9 hours (n=2) and D122 for 27 hours (n=2). Blocking experiments using neutralizing mAb against anti-type I IFNalpha/beta receptor chain2 (MMHAR-2, PBL) (anti-IFNR) were performed: 'K' ODN + anti-IFNR for 9 hours (n=2) and 'D' ODN + anti-IFNR for 27 hours (n=2).