A Vesicular Stomatitis Virus Recombinant Expressing Granulocyte-Macrophage Colony-Stimulating Factor Induces Enhanced T-Cell Responses and Is Highly Attenuated for Replication in Animals

Abstract

Live attenuated vectors based on recombinant vesicular stomatitis viruses (rVSVs) expressing foreign antigens are highly effective vaccines in animal models. In this study, we report that an rVSV (VSV-GMCSF1) expressing high levels of murine granulocyte-macrophage colony-stimulating factor (GM-CSF) from the first position in the viral genome is highly attenuated in terms of viral dissemination and pathogenesis after intranasal delivery to mice. However, this highly attenuated virus generated antibody and T-cell responses equivalent to those induced by a control virus expressing enhanced green fluorescent protein (EGFP) from the first position (VSV-EGFP1). The better containment and clearance of VSV-GMCSF1 may be due to enhanced recruitment of macrophages to the site of infection but is not explained by a greater induction of interferons. The primary CD8 T-cell and neutralizing antibody responses to VSV-GMCSF1 were equivalent to those generated by VSV-EGFP1, while the CD8 T-cell memory and recall responses to the vector were enhanced in mice infected with VSV-GMCSF1. It is likely that the GM-CSF produced by immunization with this virus results in an enhanced recruitment of antigen-presenting cells, leading to better acute and long-term T-cell responses. This recruitment appears to cancel out any negative effect of viral attenuation on immunogenicity.Recombinant vesicular stomatitis viruses (rVSVs) expressing appropriate foreign antigens have been used to generate experimental vaccines protecting against infection or disease caused by several viral pathogens (27,29,30,33). Although no pathogenesis was observed in nonhuman primates given live attenuated VSV vectors by the oral, intranasal, and intramuscular routes (5,27,31), it is likely that additional specific attenuating mutations will be required before live VSV vectors can be used in human vaccine trials. The attenuation of vector pathogenesis is often associated with a loss of immunogenicity, and a loss of immunogenicity was already reported when VSV vectors attenuated for growth were delivered intranasally (25,29). For the present study, we sought a means of attenuating VSV pathogenesis while simultaneously retaining or enhancing immunogenicity.rVSVs derived from plasmid DNA are attenuated to the point that they do not cause neuropathogenesis in 6-to 8-week-old mice after intranasal delivery, but still cause transient weight loss (29). Weight loss is a sensitive measure of pathogenesis correlating with the extent of viral replication after intranasal inoculation. We have previously tested immune responses to rVSV vectors in which the VSV G gene has been deleted. These VSV⌬G vectors are capable of only a single round of replication in the host and induce strong CD8 T-cell responses when delivered intramuscularly, but they are much less effective when delivered by the intranasal route (Publicover et al., unpublished data). In contrast, replicationcompetent rVSVs delivered intranasally generate cytotoxic T-lymphocyte (CTL) responses that are nearly indistinguis...

Peripheral, but not central nervous system, type I interferon expression in mice in response to intranasal vesicular stomatitis virus infection

“…VSV replication in peripheral organs after i.n. infection has been reported (Publicover et al, 2006;Ramsburg et al, 2005); however, those studies inoculated mice with much higher titers and in a larger volume than in our work, which can have dramatic effects on the ability of viruses to replicate in the lung (Yetter et al, 1980). Despite the small dose of virus given in our work (as low as 100 PFU in 5 μl), VSV was still able to productively infect peripheral tissues.…”

Nup98 promotes antiviral gene expression to restrict RNA viral infection in Drosophila

“…We next examined the role of Nup98 in viral infections against additional RNA viruses. First, we infected Nup98-depleted cells with VSV expressing GFP (26) and observed a threefold to fourfold increase in infection as measured by microscopy and immunoblot analyses ( . Because these viruses do not naturally infect Drosophila, but rather infect mosquitoes, we examined the role of Nup98 in the infection of a natural Drosophila pathogen, Drosophila C virus (DCV).…”

Independent of Plasmacytoid Dendritic Cell (pDC) infection, pDC Triggered by Virus-Infected Cells Mount Enhanced Type I IFN Responses of Different Composition as Opposed to pDC Stimulated with Free Virus

“…The VSV variant with mutated matrix protein 2 (VSV-M2) is a natural variant of the VSV wild-type strain HR (26,27). The eGFP-expressing variants enhanced GFP-expressing VSV (VSVeGFP) (28), expressing eGFP upon VSV replication in infected cells, and VSV-G-GFP (29), expressing GFP as a fusion protein with VSV-G, were provided by J.K. Rose. VSV-expressing red fluorescent protein (VSV-RFP) was provided by S.P.J.…”