| dc.description.abstract | The COVID-19 pandemic has caused devastating effects on the global socio-economic landscape. Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the causative agent of COVID-19, and infections have led to approximately 7 million fatalities worldwide. Previous findings have confirmed that neutralizing antibodies are a highly predictive measure of immune protection. Thus, measuring SARS-CoV-2 neutralizing responses after infection or vaccination remains a priority, especially in the event of newly emerging SARS-CoV-2 variants. Due to the limitations of working with live virus in a BSL3 facility, pseudoparticles are an alternative tool used to study viral surface proteins. This research aims to develop a SARSCoV-2 pseudoparticle system to detect neutralizing antibodies in sera from previously infected or vaccinated individuals. The use of vesicular stomatitis virus (VSV) as a vector for the pseudoparticle system, provides several advantages over the lentivirus system including faster assay time, and lack of interference from antiretroviral drugs present in sera from HIVpositive patients on antiretroviral therapy (ART). The latter is particularly relevant in South Africa where there are more than 7.8 million HIV people living with HIV. After generating VSV pseudoparticles bearing the SARS-CoV-2 spike from the Wuhan/D614G, Beta, Delta and Omicron variants, a neutralizing assay was optimized using characterized human monoclonal antibodies. The assay was then applied to a sample set of patient sera and the ID50 values were compared to those obtained using a lentivirus-based SARS-CoV-2 neutralization assay. The comparison highlighted a strong concordance between the VSV and lentivirus neutralization assays particularly for the Wuhan/D614G and Omicron variants. The findings indicate that the development of a VSV-based neutralization assay is a valuable contribution to our ongoing efforts to characterize protective immune responses arising from SARS-CoV-2 infection or vaccination. | en_US |
