Thanks Daffodil
full paper
here
analysis of this 91-bp pro sequence identified a
distinct gammaretrovirus that is equidistant from
murine endogenous retroviruses (mERVs), XMRV, and MLV
sharing only
7275% nucleotide and amino acid identity (data not
shown).
the presence of particle associated JEV RNA in the two vaccines was confirmed
A 365-bp sequence with 99% nucleotide identity to
a human genomic region (GenBank accession no. AJ289710)
annotated as the
human endogenous retrovirus type H was also
present in the JEV vaccine and most likely represents human DNA
Contamination
There are other mouse-derived biological products that may be
at a higher risk of carrying MLV, such as monoclonal antibodies
(mAbs) that are used in humans for the treatment of cancer,
inflammatory, and autoimmune diseases [30]. Indeed, mouse
hybridomas that have been shown to be contaminated with
endogenous xenotropic MLVs [30], but the production of mouse
mAbs for clinical use requires purification steps that inactivate and
remove viral particles. Our study is also limited by the testing of
only eight vaccines and does not include other live attenuated
vaccines that have a history of passage in rodents, such as early
versions of the oral polio vaccine. We also did not test master virus
seed stocks (MVSS) and master cell banks (MCB) used in the
manufacture of the live attenuated vaccines from our study since
these materials were not readily available.
Although we did not find XMRV or MLV in any of the eight
vaccines, our data reveal that the live attenuated JEV vaccine (SA-
14-14-2) contains multiple hamster genomic DNA and endogenous
gammaretrovirus sequences that are distantly related to MLV.
Merry Christmas everyone!