Tick Cell Lines for Study of Crimean-Congo Hemorrhagic Fever Virus and Other Arboviruses

Abstract

Continuous cell lines derived from many of the vectors of tick-borne arboviruses of medical and veterinary importance are now available. Their role as tools in arbovirus research to date is reviewed and their potential application in studies of tick cell responses to virus infection is explored, by comparison with recent progress in understanding mosquito immunity to arbovirus infection. A preliminary study of propagation of the human pathogen Crimean-Congo hemorrhagic fever virus (CCHFV) in tick cell lines is reported; CCHFV replicated in seven cell lines derived from the ticks Hyalomma anatolicum (a known vector), Amblyomma variegatum, Rhipicephalus (Boophilus) decoloratus, Rhipicephalus (Boophilus) microplus, and Ixodes ricinus, but not in three cell lines derived from Rhipicephalus appendiculatus and Ornithodoros moubata. This indicates that tick cell lines can be used to study growth of CCHFV in arthropod cells and that there may be species-specific restriction in permissive CCHFV infection at the cellular level.

Susceptibility of tick cell lines to infection with Alkhumra haemorrhagic fever virus

“…24 Similarly, Crimean-Congo haemorrhagic fever virus replication as measured by real-time RT-PCR was 10-100-fold higher in cell lines derived from the vector tick species H. anatolicum than in non-vector cell lines. 19 In the present study, yield of viable AHFV from the O. moubata cell line (OME/CTVM24) was ≥10-fold higher than that from the R. appendiculatus cell line (RAE/CTVM1), whilst the H. anatolicum cell line (HAE/CTVM9) appeared to be incapable of supporting production of virus capable of infecting and causing a cytopathic effect in LLC-MK2 cells. It is unclear whether this in vitro pattern reflects real differences in natural vectorial or reservoir host capacity of these tick genera in vivo.…”

“…Tick cell lines are both phenotypically and genotypically diverse 19 and very little is known about the range of cell phenotypes within a particular line, apart from easily recognisable cell types such as hemocytes. It is not known which cells play an important role in AHFV replication in any arthropod.…”

“…Such a phenomenon is not unique to AHFV as similar behaviour was previously reported for Langat virus, West Nile virus (WNV), Venezuelan equine encephalitis virus, Ganjam virus, 20,21 and many other mosquitoborne arboviruses as reviewed recently. 19 Early attempts to propagate arboviruses in arthropod cell lines were predominantly carried out in mosquito-derived cell lines. 22 With the introduction of tick-derived cell lines, a range of arboviruses were found to replicate in these cell lines.…”

“…22 With the introduction of tick-derived cell lines, a range of arboviruses were found to replicate in these cell lines. 19,20 Tick cell lines were subsequently employed to investigate different aspects of the relationship between tick-borne encephalitis virus and ticks at the cellular and molecular levels. 19,23 Growth of arboviruses in vector and non-vector tick cell lines produced interesting findings.…”

“…19,20 Tick cell lines were subsequently employed to investigate different aspects of the relationship between tick-borne encephalitis virus and ticks at the cellular and molecular levels. 19,23 Growth of arboviruses in vector and non-vector tick cell lines produced interesting findings. In a study by Rů zek et al, it was found that there was a clear difference between tick-borne encephalitis virus growth in vector and non-vector tick cell lines.…”