Fig. 4
A, B Titration curves showing the binding efficiency of two antibodies; Covat (study mAb from clone 12–3H1–2) and Commercial mAb (2G4–H1–B2–C3, Cat No. 130–10836) against commercial antigen (Nagasaki, DIA-5028) and study recombinant antigen, respectively. Antibody concentrations range from 2.0 to 0.03125 µg/ml. Statistical comparison using the Kruskal–Wallis test showed no significant difference in binding (p = 0.072 and p = 0.12 for panels A and B, respectively) C Binding activity of varying concentrations of our monoclonal antibody against SARS-CoV-2 beta and omicron variants from Kenya and Japan, respectively. The monoclonal antibody with decreasing concentrations (10 µg/ml, 5 µg/ml, 2.5 µg/ml, 1.25 µg/ml and 0.625 µg/ml) showed strong and consistent signal against the virus infected culture fluid (ICF) both Beta (3.45 × 105 PFU/mL) and Omicron (3.45 × 105 PFU/mL) SARS-CoV-2 variants, with minimal reduction in optical density. D Correlation between RT-qPCR cycle threshold (CT) values and ELISA absorbance at 492 nm. An inverse relationship was observed (R2 = 0.915), indicating high assay sensitivity.