The ongoing COVID-19 pandemic has presented many challenges worldwide. For a while, it seemed that the more we learned about the virus, the more we realized we didn’t know enough. One thing is certain, with new and effective vaccines against SARS-CoV-2 soon to be released, we have begun to see the light at the end of the tunnel. Still, vaccine distribution will be challenging, given that the need is almost unsurmountable.
During the pandemic, the wheels of innovation have been hard at work spinning new therapeutic and diagnostic tools. GenScript joined the efforts early on by developing a variety of resources to accelerate SARS-CoV-2 research, including Spike/RBD monoclonal antibodies, gram level Spike/RBD proteins, ACE2 expressing cell lines, and SARS-CoV-2 peptide libraries.
For diagnostics, GenScript teamed up with Professor Linfa Wang, Ph. D., at Duke-NUS Medical School and National Centre for Infectious Disease, Singapore, to develop a test to detect SARS-CoV-2 neutralizing antibody responses, which could support not only infection detection efforts but also enable vaccine efficacy evaluation (Tan et al. 2020). GenScript acquired CE-IVD mark for cPass™ in May, allowing distribution in Europe and other international markets. On November 6th, the FDA granted an Emergency Use Authorization to GenScript's cPass™ SARS-CoV-2 Neutralization Antibody Detection Kit for use as an in-vitro diagnostics test. The FDA’s authorization for the use of cPass™ by high complexity CLIA certified laboratories in the US will allow health care providers to test whether patients have been exposed to the SARS-CoV-2 virus and generated neutralizing antibodies by detecting the presence of an adaptive immune response. This emergency authorization makes cPass™ the only authorized test in the market to qualitatively detect total neutralizing antibodies to SARS-CoV-2.
Broadly defined, neutralizing antibodies not only bind specifically to a virus but also inhibit viral infection and are thought to represent the best correlate of protection following vaccination (Klasse, 2014). In agreement with this notion, several studies so far have indicated the relevance of anti-SARS-CoV-2 antibodies and specifically those binding to the Spike/RBD domain in protective immunity (Addetia et al. 2020, Carrillo et al. 2020, Wajnberg et al. 2020).
The cPass™ kit was developed to provide a fast, specific and safe approach to the detection of SARS-CoV-2 neutralizing antibodies. The test is based on a blocking ELISA assay, where the ACE2 receptor is immobilized and binding to the soluble Spike/RBD domain is inhibited only in the presence of neutralizing antibodies, such as those which may be found in convalescent plasma. Because the cPass™ kit does not rely on cell lines or a live virus, it's safe and does not require BSL3 containment conditions. Additionally, the cPass™ kit provides expedited results within 1-2hours.
Much work remains to be done to understand whether vaccine induced immunity to SARS-CoV-2 is long-lasting. In this regard, our work has just begun. Immune responses will need to be closely monitored to fully understand the efficacy of vaccines and to identify best correlates of protection. To this end, the cPass™ test may help support vaccine efficacy evaluation and herd immunity assessments.
