In vivo biodistribution of a highly attenuated recombinant vesicular stomatitis virus expressing HIV-1 Gag following intramuscular, intranasal, or intravenous inoculation

Abstract

Recombinant vesicular stomatitis viruses (rVSVs) are being developed as potential HIV-1 vaccine candidates. To characterize the in vivo replication and dissemination of rVSV vectors in mice, high doses of a highly attenuated vector expressing HIV-1 Gag, rVSV IN -N4CT9-Gag1, and a prototypic reference virus, rVSV IN -HIVGag5, were delivered intramuscularly (IM), intranasally (IN), or intravenously (IV). We used quantitative, real-time RT-PCR (Q-PCR) and standard plaque assays to measure the temporal dissemination of these viruses to various tissues. Following IM inoculation, both viruses were detected primarily at the injection site as well as in draining lymph nodes; neither virus induced significant weight loss, pathologic signs, or evidence of neuroinvasion. In contrast, following IN inoculation, the prototypic virus was detected in all tissues tested and caused significant weight loss leading to death. IN administration of rVSV IN -N4CT9-Gag1 resulted in detection in numerous tissues (brain, lung, nasal turbinates, and lymph nodes) albeit in significantly reduced levels, which caused little or no weight loss nor any mortality. Following IV inoculation, both prototypic and attenuated viruses were detected by Q-PCR in all tissues tested. In contrast to the prototype, rVSV IN -N4CT9-Gag1 viral loads were significantly lower in all organs tested, and no infectious virus was detected in the brain following IV inoculation, despite the presence of viral RNA. These studies demonstrated significant differences in the biodistribution patterns of and the associated pathogenicity engendered by the prototypic and attenuated vectors in a highly susceptible host.

A Novel, Live-Attenuated Vesicular Stomatitis Virus Vector Displaying Conformationally Intact, Functional HIV-1 Envelope Trimers That Elicits Potent Cellular and Humoral Responses in Mice

“…This contrasted sharply with the morbidity and mortality observed in animals that were inoculated the progenitor vector rVSV-G 4 (Fig.5) or the results observed in earlier studies with the VSV-Gag 4 -G 5 prototype VSV-HIV vector [24] It well known that mice are highly susceptible to VSV neuroinvasion when they are experimentally infected by IN administration or by other routes, and that susceptibility is age-dependent with young mice being prone to encephalitis; thus, rodent models have been used to study VSV neurovirulence and have been used to evaluate potential risk of using VSV vectors in [62], [89]–[91]. It also is known that considerable vector engineering is needed to generate genetically stable vectors that exhibit substantially reduced neurovirlence in the murine model, and that it is very difficult to completely eliminate the appearance of viral nucleic acid in the brain particularly after IN inoculation even with modified VSV that has been attenuated sufficiently to prevent symptoms [62]. Consistent with these earlier findings, rVSV-EnvG 4 -G 6 gRNA was detectable in whole brain extracts prepared from mice vaccinated by the IN route, but it is important to note that N mRNA quantities were just above the limit of detection in only 1 of 4 animals indicating that gene expression and replication in the brain was quite restricted, which was consistent with our observation of no significant weight loss, absence of fever, and no distress caused by rVSV-EnvG 4 -G 6 vaccination.…”

Vesicular Stomatitis Virus Genomic RNA PersistsIn Vivoin the Absence of Viral Replication

“…A recent study has also reported the concentration in lymph nodes and long-term persistence of rwt and other attenuated VSV vector RNAs after i.m. inoculation of mice (12).…”

Preclinical Pharmacokinetics and Biodistribution of Human Papillomavirus DNA Vaccine Delivered in Human Endogenous Retrovirus Envelope-Coated Baculovirus Vector

“…For example, adenovirus type 5-vectored DNA vaccine was found to be biodistributed only to spleen and liver through binding to coxsackievirus and adenovirus receptor (23). Recombinant vesicular stomatitis virus expressing HIV-1 Gag showed greater persistence in lymph nodes compared to other tissues after intramuscular administrations (24).…”