Adenovirus 5 Vectors Expressing SARS-CoV-2 Proteins.

SARS-CoV-2 coronavirus is a recently identified novel coronavirus that is the causative agent of the COVID-19 pandemic that began in 2020. An intense research effort has been undertaken by the research community in order to better understand the molecular etiology of this virus and its mechanisms of host cell subjugation and immune system evasion. To facilitate further research into the SARS-CoV-2 coronavirus we have generated adenovirus 5-based viral vectors that express SARS-CoV-2 proteins-S, N, E, NSP7, NSP8, and NSP12 as hemagglutinin (HA)-tagged and untagged variants. We have also engineered two additional viruses that express the S protein receptor binding domain and a fusion of the receptor binding domain to the N protein. We show that these vectors are expressed in several different cell lines by Western blotting and real-time quantitative reverse transcriptase (qRT-PCR), we evaluate the subcellular localization of these viral proteins, and we show that these coronavirus proteins bind to a variety of cellular targets. The flexibility of adenovirus vectors allows them to be used in a variety of cell models and, importantly, in animal models as well. IMPORTANCE The COVID-19 pandemic caused by the SARS-CoV-2 coronavirus has brought untold personal and economic suffering to the world. Intense research has made tremendous progress in understanding how this virus works, yet much research remains to be done as new variants and continued evolution of the virus keep shifting the rules of engagement on the pandemic battlefield. Therefore, wide availability of resources and reagents to study SARS-CoV-2 is essential in overcoming the pandemic and for the prevention of future outbreaks. Our viral vectors provide additional tools for researchers to use in order to better understand the molecular biology of virus-host interactions and other aspects of SARS-CoV-2.

Frontrunners in the race to develop a SARS-CoV-2 vaccine.

Numerous studies continue to be published on the COVID-19 pandemic that is being caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Given the rapidly evolving global response to SARS-CoV-2, here we primarily review the leading COVID-19 vaccine strategies that are currently in Phase III clinical trials. Nonreplicating viral vector strategies, inactivated virus, recombinant protein subunit vaccines, and nucleic acid vaccine platforms are all being pursued in an effort to combat the infection. Preclinical and clinal trial results of these efforts are examined as well as the characteristics of each vaccine strategy from the humoral and cellular immune responses they stimulate, effects of any adjuvants used, and the potential risks associated with immunization such as antibody-dependent enhancement. A number of promising advancements have been made toward the development of multiple vaccine candidates. Preliminary data now emerging from phase III clinical trials show encouraging results for the protective efficacy and safety of at least 3 frontrunning candidates. There is hope that one or more will emerge as potent weapons to protect against SARS-CoV-2.