A recombinant rabies virus expressing vesicular

A recombinant rabies virus expressing vesicular stomatitis virus glycoprotein (VSV-G) is a genetically engineered virus designed for potential use as a vaccine or vector for gene therapy. 

Rabies Virus:

Rabies is a deadly viral disease that affects the central nervous system. It is typically transmitted through the bite of an infected animal, such as a dog or bat. Rabies virus belongs to the Rhabdoviridae family.

Vesicular Stomatitis Virus Glycoprotein (VSV-G):

VSV-G is a protein found on the surface of vesicular stomatitis virus (VSV), which is another type of virus. VSV is relatively harmless to humans but can infect animals, including livestock. VSV-G is often used in genetic engineering as a tool to pseudotype (disguise) other viruses, such as rabies virus, to enhance their ability to infect target cells.

Recombinant Virus:

Recombinant DNA technology is used to insert genetic material from one organism into the genome of another. In this case, genes encoding VSV-G are inserted into the genome of a rabies virus. As a result, the recombinant virus expresses VSV-G on its surface.


By expressing VSV-G, the recombinant rabies virus gains the ability to infect cells that it typically wouldn't be able to infect. This can enhance the virus's ability to deliver genetic material (such as genes encoding antigens for vaccine purposes or therapeutic genes for gene therapy) to target cells.

Such a recombinant rabies virus expressing VSV-G could potentially be used in various applications:

Vaccine Development:

The recombinant virus could be developed as a vaccine candidate against rabies or other diseases. By expressing rabies antigens along with VSV-G, the virus could induce a strong immune response against both rabies and the inserted antigen.

Gene Therapy:

The recombinant virus could be used as a vector for delivering therapeutic genes to target cells. By pseudotyping with VSV-G, the virus may gain improved ability to enter specific types of cells, potentially enhancing the effectiveness of gene therapy treatments.


Synthesis of infectious recombinant rabies virus particles from cloned cDNA


To investigate the importance of rabies virus (RV) glycoprotein (G) in protection against rabies, we constructed a recombinant RV (rRV) in which the ecto- and transmembrane domains of RV G were replaced by the corresponding regions of the vesicular stomatitis virus (VSV) glycoprotein (rRV-VSV-G). We were able to recover rRV-VSV-G and found that the particle production was equal to rRV.

However, budding of the chimeric virus was delayed and infectious titers were reduced 10-fold compared to the parental strain of rRV containing RV G. Biochemical analysis showed equal replication rates of both viruses, and amounts Similar wild type and chimeric G were present.

in the respective viral particles. Additional studies were performed to determine if the immune response against rRV-VSV-G was sufficient to protect against rabies. Mice were primed with rRV or rRV-VSV-G and challenged with a pathogenic strain of RV 12 days later. Similar immune responses against internal viral proteins of both viruses indicated successful infection. All mice receiving the rRV vaccine survived the challenge, while immunization with rRV-VSV-G did not induce protection. The results confirm the crucial role of RV G in an RV vaccine.

Rabies virus (RV), a negative-strand RNA virus, belongs to the genus Lyssavirus within the family Rhabdoviridae. Five structural proteins, including nucleoprotein (N), phosphoprotein, matrix protein (M), glycoprotein (G), and RNA-dependent RNA polymerase (L), are encoded by the 12 kb viral genome.

G, the only protein exposed on the surface of the virus particle, mediates both binding to cell receptors and entry into host cells. Being a highly immunogenic protein, virus-neutralizing antibodies that are induced against this protein (1, 2) protect against RV infection (3). In addition, RV G induces cytotoxic T lymphocytes (4) and helper T cells (5).

Although RV G appears to be the primary determinant of protection against RV infection, some researchers have reported that it is not essential in a rabies vaccine. Immunization of mice and raccoons with ribonucleoprotein RV (RNP) in complete Freund's adjuvant resulted in protection (6). Moreover, administration of N alone or via an RV N-expressing viral vector resulted in protection against lethal challenge with RV (7–9).

On the other hand, others have reported only partial protection after immunization with RV N and suggest that immunization reduces the incubation period and clinical symptoms of rabies (10). Therefore, the question of the importance of RV G alone or in combination with N in protection remains. Further clarification of this debate will help to develop more effective vaccines.

The development of an efficient salvage system for the rescue of infectious RV from cDNA has enabled direct manipulations of the RV genome and the production of genetically engineered recombinant viruses. Using this technology, RVs expressing stable heterologous proteins were rescued. Foreign genes such as CAT (11), CD4 and CXCR4 (12) or HIV-1 gp160 (13) have been inserted into the RV genome, in addition to the five standard genes.

An advantage of rhabdovirus-based vectors is the ability to incorporate foreign glycoproteins into viral particles. For RV, this process requires replacement of the cytoplasmic domain of the foreign glycoprotein with the corresponding fragment of RV G (12, 14). This process appears to be different for vesicular stomatitis virus (VSV), another rhabdovirus.

The incorporation of foreign glycoproteins into VSV particles depends only on the expression level of the glycoproteins and does not require any modification (15-17). Moreover, VSV even incorporates its own glycoprotein containing a foreign cytoplasmic domain as efficiently as the G protein of wild-type VSV.