Expression of HIV-1 Gag and Env Genes Using the Vesicular Stomatitis Virus Vector System

Traditional vaccine methods have long been employed to control widespread infectious diseases, but so far, all commercially available vaccine strategies have been inadequate in efforts to develop an effective therapeutic HIV vaccine. However, recent advancements in immunological research have led to the generation of novel vaccine strategies, one of which is the recombinant virus vaccine, a method of particular interest that has shown promise in the clearance of HIV infection within HIV-positive patients who have retained immunocompetence. This study examined the stability of expression of HIV-1 genes, gag and env, through a recombinant virus vector, a recombinant vesicular stomatitis virus (VSV), a temperature-sensitive mutant genetically modified to contain the select HIV-1 genes (VSVInd(GML)HIV-1gagenv). For SDS-PAGE, cells infected with VSVInd(GML) temperature-sensitive mutants were incubated at 31 °C and 37 °C, representing permissible and semi-permissible growth conditions respectively. Western blot analyses were used to quantitate levels of protein expression of full VSV proteins, Gag, and Env using a primary rabbit antibody of anti-VSV anti-serum and a secondary anti-IgG from rabbit, a primary antibody of anti-p24 anti-serum and a secondary anti-IgG from rabbit, and a primary goat antibody, anti-gp120, and a secondary anti-IgG from goat, respectively. Results indicated that the VSVInd(GML) vector system allowed for high levels of expression of HIV-1 gag and env genes. It is known that the expression of these genes induce the production of major neutralizing antibodies and the stimulation of cytotoxic T lymphocytes, therefore this finding reveals the potential to use a genetically modified recombinant VSV as a universal vector for the development of recombinant virus vaccines. Specifically, the VSVInd(GML) mutant vector is thus an attractive candidate for the viral vector of a therapeutic HIV vaccine system. Introduction According to the World Health Organization report in 2013, HIV has infected over 70 million people and 36 million people have died from AIDS-related illnesses since 19811. Additional reports from United Nations AIDS disclosed that 2.3 million people were newly infected in 2012, adding to a total of 35.3 million people diagnosed with HIV infection as of 20132. HIV/AIDS is a rising world epidemic and our search for a method to control the spread of this disease has presented one of the most challenging problems of the past three decades. Vaccines are one of the most effective methods of controlling infectious disease and thus a central focus for HIV treatment has been on efforts to develop an effective therapeutic vaccine that will clear HIV infection. There are three types of commercially available vaccine strategies used to prevent many different viral diseases. These include the live-attenuated virus vaccine, such as the measles and mumps vaccines, the killed whole-virus vaccine, such as the influenza and hepatitis A vaccines, and subunit vaccines, such as human hepatitis B virus and human papilloma virus vaccines. However, these three conventional vaccine strategies have so far proved ineffective for use as therapeutic HIV vaccine systems, effectively demonstrating our limited and largely empirically-based knowledge of these technologies and our lack of a comprehensive understanding of the immunological principles underlying widespread infectious diseases such as HIV2,3,4. Recent advancements however, have generated novel vaccine strategies, one of which is the recombinant virus vaccine, a method that has shown to be promising in clearance of HIV infection within HIV-positive patients who have retained immunocompetence5. Recombinant virus vaccines depend on the use of a viral vector to carry genes of interest, such as HIV genes, and express them in the body to activate CD8 positive cytotoxic T lymphocytes (CTLs). Development of a therapeutic HIV vaccine to clear persistently infected Research Article: Expression of HIV-1 gag and env genes Health and Natural Sciences WURJ