The Virology of Taterapox Virus In Vitro.

Scott Parker,Robert Buller,Hollyce Hartzler,Leonardo Camilo De Oliveira,Robert Hendrickson,Ryan Crump,Elliot Lefkowitz,William Wold,Cláudio Bonjardim

doi:10.3390/v10090463

Abstract

Taterapox virus (TATV) is phylogenetically the closest related virus to variola—the etiological agent of smallpox. Despite the similarity, few studies have evaluated the virus. In vivo, TATV can infect several animals but produces an inapparent infection in wild-type mice; however, TATV does cause morbidity and mortality in some immunocompromised strains. We employed in vitro techniques to compare TATV to ectromelia (ECTV) and vaccinia (VACV) viruses. Both ECTV and TATV replicate efficiently in primate cell lines but TATV replicates poorly in murine cells lines. Furthermore, TATV induces cytopathic effects, but to a lesser extent than ECTV, and changes cytoskeletal networks differently than both ECTV and VACV. Bioinformatic studies revealed differences in several immunomodulator open reading frames that could contribute to the reduced virulence of TATV, which were supported by in vitro cytokine assays.

Highlights

Variola virus (VARV) is the etiological agent of smallpox
Taterapox virus (TATV) has a genome of approximately 196 kbp and encodes for 162 haploid and two diploid full length open reading frames (ORFs); 23 haploid and four diploid truncated ORFs; and six fragmented ORFs
ORFs located outside of the central conserved region (CCR) are typically considered to be involved in virulence and host-range and are hypothesised to be tailored to the appropriate host(s) of each OPV

Summary

Introduction

Variola virus (VARV) is the etiological agent of smallpox. Only the original report describing the virus in 1975 had been published [4]. This paper by Lourie et al revealed that a sole TATV isolate was recovered from an apparently healthy wild gerbil (Tatera kempi or Gerbilliscus kempi) captured in what is the Republic of Benin. The assays performed in 1975 revealed that, when compared to other OPVs, TATV had many similar characteristics to VARV; in vivo assays were limited in number and description. In 2017, Parker et al published a report that described TATV challenges in several small animals and found that the virus failed to induce significant morbidity in gerbils or wild-type mice but did induce seroconversion [5].

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Conclusion