Severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) or COVID-19 is a novel respiratory coronavirus that was first isolated in December 2019 from three people connected to a cluster of pneumonia cases in Wuhan City, China. As of May 5 2021, SARS CoV2 has spread globally to nearly every country, infecting more than 154 million people and leading to more than 3.23 million deaths. The R0 (nought/zero) of SARS CoV2, which measures its contagiousness, is 2-2.5, which means that one infected individual can spread the virus to more than 2 individuals. This R0 is higher that the Ro of the 1918 influenza virus that killed over 50 million people worldwide, which makes SARS CoV2 a highly contagious virus.
SARS CoV2 in research, and in vaccine and antiviral development
The publication of the genetic sequence of the SARS CoV2 in January 2020 has greatly helped the research community in understanding this pathogenic coronavirus, and has sped up progress in development of vaccines, drugs and antibodies against SARS CoV2. Developing new drugs and antibodies, collectively known as antivirals, will require testing against SARS CoV2. However, SARS CoV2 is highly contagious and use of this coronavirus requires a minimum biosafety level (BSL) 3 facility. Unfortunately, BSL3 facilities are very limited and this can severely limit testing of antivirals against SARS CoV2.
SARS CoV2 vector to study viral entry and for testing antivirals.
At Tailored Genes, we have developed eGFP and luciferase containing SARS CoV2 vector that can be safely used in a BSL2 facility. Our vector is a hybrid between a lentivirus vector and SARS COV2 spike protein. The spike protein sequence is of the original Wuhan strain of SARS CoV2. Our vector carries markers such as the eGFP gene which allows the visualization of infected cells. The figure on the left show infection of ACE2 expressing cells with the eGFP containing SARS CoV2 vector. Our vector is of high titer (10e8 IU/mL) and high purity thus increasing transduction efficiency of target cells. Our vector will allow the study of SARS CoV2 entry and the testing of antivirals in neutralization assays
Variants of SARS CoV2
Virus replication often leads to mutations in the new virus particles that arise from infected cells. Mutant viruses that gain advantage to survive such as in increased transmissibility or to evade the body’s immune system will increase in frequency and will become the predominant mutant or variant of the virus that is then transmitted further into the human/animal population.
One of the first variant of SARS CoV2 to emerge and establish in March 2020 was a D614G variant which is now found globally. this variant has the D614G mutation in the spike protein that is required for virus binding and entry. As a result this variant appears to spread rapidly. Further mutations in the spike protein in select geographic regions has led to emergence of highly transmissible SARS CoV2 variants. The emergence of three such variants (UK , South Africa, and Brazil) has heightened concerns.
SARS CoV2 vector variants (UK, South Africa, Brazil and India)
We have developed eGFP and luciferase containing SARS CoV2 vectors bearing the spike variant from UK, and from South Africa. Like our Wuhan SARS CoV2 vector, the UK and South Africa variant vectors are of high titer (10e8 IU/ml) and high purity. Our vectors will allow researchers to determine whether antivirals developed against the original Wuhan strain will be effective against the UK and South African variant and allow testing of new antivirals against these variants.
We are also in the process of developing SARS CoV2 vectors with the Brazil and India spike variant.
LVV with SARS CoV2-S gene.
Tailored Genes has also developed lentivirus vector with the SARS CoV2 spike gene. Transduction of target cells with LVV CoV2-S results expression of SARS CoV2-S spike protein. The LVV CoV2-S is of high purity and of high titer (10e8 IU/mL). This vector will allow studies to explore CoV2 spike protein expression on target cell growth and viability.
The LVV CoV2-S is available upon request.