Recombinant CCHFV Gc [His]

In this article, the development of a new TaqMan-based one-step real-time reverse transcriptase-polymerase chain reaction (RT-PCR) assay for detection and quantification of Crimean-Congo hemorrhagic fever virus (CCHFV) RNA is described. Selected oligos targeting the highly conserved S region of CCHFV were designed by using our oligo design and analysis software, Oligoware 1.0. None of the primer sequences showed genomic cross-reactivity with other viruses or cells in a BLAST (NCBI) search analysis. The sensitivity and specificity of the primers and the probe were tested using 18 serum samples from patients from EastAnatolian who were suspected of having CCHFV, including 2 samples that had already been confirmed to be positive for CCHFV. Among the 16 previously unconfirmed samples, 5 were positive by TaqMan-based one-step real-time RT-PCR and 1 was positive by non-nested RT-PCR, and these results were confirmed with DNA sequencing analysis. The 2 previously confirmed CCHFV RNA samples were also positive by both TaqMan-based one-step real-time RT-PCR and non-nested RT-PCR tests. To ensure the quantitative reproducibility of TaqMan-based one-step real-time RT-PCR, the procedure was repeated several times and the same results were obtained (SD = 0.84 [maximum value]). The developed assay was able to sensitively quantify the concentration of CCHFV RNA, which ranged from 10(2) to 10(7) copies/ml per reaction, using plasmid standards generated from the CCHFV RNA (correlation coefficiency = 0.989). The results of the one-step real-time RT-PCR assay were more sensitive than those of the non-nested RT-PCR assay. It can be concluded that our one-step real-time RT-PCR assay is a reliable, reproducible, specific, sensitive and simple tool for the detection and quantification of CCHFV.

Crimean-Congo hemorrhagic fever virus (CCHFV) is a member of the family Bunyaviridae and is a causative agent of severe hemorrhagic disease. Knowledge regarding the pathogenesis of CCHFV is limited due to the requirement for high-containment laboratories and the lack of an immunocompetent animal host. Previous studies have shown that CCHFV delays the activation of the human innate immune response, specifically, the type I interferon response. Our study results show that antagonism of the interferon-beta promoter is mediated by the nucleoprotein of CCHFV strain Hoti, while strains IbAr10200 and AP92 do not suppress the activity of the IFN-beta promoter. Our results also suggest that several viral factors may provide antagonistic action against the type I interferon response.