Enhanced pseudotyping efficiency of HIV-1 lentiviral vectors by a rabies/vesicular stomatitis virus chimeric envelope glycoprotein.

Rabies virus glycoprotein (RVG) can pseudotype lentiviral vectors, although at a lower efficiency to that of vesicular stomatitis virus glycoprotein (VSVG). Transduction with VSVG-pseudotyped vectors of rodent central nervous system (CNS) leads to local neurotropic gene transfer, whereas with RVG-pseudotyped vectors additional disperse transduction of neurons located at distal efferent sites occurs via axonal retrograde transport. Attempts to produce high-titre RVG-pseudotyped lentiviral vectors for preclinical and clinical trials has to date been problematic. We have constructed several chimeric RVG/VSVG glycoproteins and found that a construct bearing the external/transmembrane domain of RVG and the cytoplasmic domain of VSVG shows increased incorporation onto HIV-1 lentiviral particles and has increased infectivity in vitro in 293T cells and in differentiated neuronal cell lines of human, rat and murine origin. Stereotactic application of vector pseudotyped with this RVG/VSVG chimera in the rat striatum resulted in efficient gene transfer at the site of injection showing both neuronal and glial tropism. Distal neuronal transduction in the substantia nigra, thalamus and olfactory bulb via retrograde axonal transport also occurs after intrastriatal administration of chimera-pseudotyped vectors at similar levels to that observed with a RVG-pseudotyped vector. This is the first report of distal transduction in the olfactory bulb. The enhanced pseudotyping with this envelope should enable easier production of higher-titre pseudotyped lentiviral vectors that exhibit efficient local and dispersed neuronal transduction in the CNS.

Role of infectious secretions in the transmission of rhinovirus.

In a series of studies aimed at investigating the role of environmental surfaces in the transmission of certain respiratory virus infections, it was shown that small amounts of nasal mucus containing rhinovirus (infectious mucus) can spread from fingertips to door knobs, faucet handles, or other environmental surfaces and remain infectious for many hours. These surfaces can serve as a reservoir of virus and may provide sufficient infectious material to contaminate hands. Recent studies have shown that once virus is on the fingers, it may be transferred to the nasal and conjunctival mucosa by means of autoinoculation. It has been estimated that as little as 1.0 plaque-forming unit can produce an infection in a susceptible human. In the present experiments, the amount of rhinovirus transmitted from fingers contaminated with infectious mucus to environmental surfaces and from there onto the fingers of a volunteer who touched the contaminated objects was quantitated, and the efficiency of transfer was studied. From 3 to 1,800 plaque-forming units of rhinovirus were recovered from the fingertips of volunteers (recipients) who handled either a door knob or a faucet that had previously been manipulated by another volunteer (donor) whose fingers were contaminated with infectious mucus. The average amount of rhinovirus recovered from the fingers of the recipients was approximately 13.5% of the amount recoverable from the fingers of the donor. In experiments in which there was direct hand-to-hand contact between donor and recipient, about 6.7% of the virus present on the fingertips of donors was recoverable from the recipients.