Serological assessment of SARS-CoV-2 infection during the first wave of the pandemic in Louisville Kentucky.

Serological assays intended for diagnosis, sero-epidemiologic assessment, and measurement of protective antibody titers upon infection or vaccination are essential for managing the SARS-CoV-2 pandemic. Serological assays measuring the antibody responses against SARS-CoV-2 antigens are readily available. However, some lack appropriate characteristics to accurately measure SARS-CoV-2 antibodies titers and neutralization. We developed an Enzyme-linked Immunosorbent Assay (ELISA) methods for measuring IgG, IgA, and IgM responses to SARS-CoV-2, Spike (S), receptor binding domain (RBD), and nucleocapsid (N) proteins. Performance characteristics of sensitivity and specificity have been defined. ELISA results show positive correlation with microneutralization and Plaque Reduction Neutralization assays with infectious SARS-CoV-2. Our ELISA was used to screen healthcare workers in Louisville, KY during the first wave of the local pandemic in the months of May and July 2020. We found a seropositive rate of approximately 1.4% and 2.3%, respectively. Our analyses demonstrate a broad immune response among individuals and suggest some non-RBD specific S IgG and IgA antibodies neutralize SARS-CoV-2.

Stability of plasmid and viral banks supporting the cGMP manufacture of Q-Griffithsin from a TMV-based viral vector.

The "whole genome" TMV-based expression system, Geneware®, was used in the cGMP production of the plant-made pharmaceutical Q-Griffithsin and demonstrates stable expression for up to a two-year period. Virion and plasmid banks which contained viral cDNA and a Q-Griffithsin sequence were able to produce >200 g of Q-Griffithsin. Data assessing the quality and stability of the product banks were measured through functional assessments of visual symptomology and product expression.