A new murine virus may be an old story retold

According to Charles River scientists, a new murine virus described in a February online article of the Journal of Virology is not so new after all. In the article, lead author Swapneel J. Patel of the Division of Rheumatology at Washington University in St. Louis and his cohorts describe a virus they call murine roseolovirus (MRV). Through genome sequencing, they demonstrate that the virus is related to the roseolovirus genus and human herpesviruses 6A (HHV-6A), HHV-6B, and HHV-7.

However, Senior Scientist Chuanwu Wang with Charles River’s infectious disease molecular diagnostics department in Wilmington, MA, says the virus they describe is not novel. He believes that it is in fact mouse thymic lymphotropic virus (MTLV), a virus that has been studied for decades.

“We got most of the genome sequences of MTLV in November 2016,” Wang said. “During the serology assay development in March 2017, we found there is one sequence, named as MRV, already deposited in GenBank. We download the whole sequence of MRV and aligned it with my MTLV. The results showed that the sequence we determined for MTLV is 100% identical to the newly reported MRV.”

Wang’s commentary, co-authored by two other scientists from Charles River, will be published this fall in the Journal of Virology, and will also be presented as a poster during the 68th American Association for Laboratory Animal Science (AALAS) meeting in October. The poster and the article will demonstrate that MRV is really just MTLV with a new name, as demonstrated by the CRL scientists’ work on rapidly sequencing the MTLV genome through Next Generation Sequencing.

The issue is not merely one of semantics. If any organism of interest to researchers is known under multiple names, it can lead to confusion and needlessly duplicated research. If a scientist is researching a particular organism, it is important that they be able to find all available research on that organism without worrying about a possible alias.

Furthermore, since the virus is often studied through animal models, the name confusion could violate the “reduction” portion of the 3Rs of humane animal research (Replacement, Reduction and Refinement). If the viruses are incorrectly thought to be separate, animal model research of the virus will be replicated instead of reduced.

“The key issue is that the whole genome sequence of MTLV is not known,” Wang said. “Currently, detection of MTLV antibodies for serological assays requires virus antigen that is produced either by virus propagation in cell culture or by the inoculation of weanling mice to acquire infected tissue. From a 3Rs point view, sequencing MTLV will allow us to identify a virus protein that could be expressed to simplify and improve antigen production. In other words, if we know the sequence of MTLV, we can synthesize one specific fragment of MTLV after bioinformatical computation, rather than rely on animals for antigen production.”

Since the virus in question may be valuable for research on human herpesvirus infections, the matter of the name is singularly important. Research on the virus cannot be fragmented, and in terms of humane animal testing, it should not be needlessly duplicated.