VLP-ELISA for the Detection of IgG Antibodies against Spike, Envelope, and Membrane Antigens of SARS-CoV-2 in Indian Population

• Published in: Vaccines (Basel) 2023-03, Vol.11 (4), p.743
• Main Authors: Kumar, Dilip, Roy, Sourav Singha, Rastogi, Ruchir, Arora, Kajal, Undale, Avinash, Gupta, Reeshu, Arora, Nupur Mehrotra, Kundu, Prabuddha K
• Format: Article
• Language: English
• Subjects: Antibodies; Antigens; Asymptomatic; Batch culture; Coronaviruses; COVID-19; COVID-19 vaccines; Disease transmission; ELISA; Enzyme-linked immunosorbent assay; Epidemiology; Fermentation; Identification and classification; Immunoglobulin G; Infections; Membranes; Methods; nanoparticle tracking analysis; Nanoparticles; Potassium; Proteins; Sensitivity analysis; Serology; Severe acute respiratory syndrome coronavirus 2; Spike protein; Virus-like particles
• ISSN: 2076-393X; 2076-393X
• DOI: 10.3390/vaccines11040743

Serological methods to conduct epidemiological survey are often directed only against the spike protein. To overcome this limitation, we have designed PRAK-03202, a virus-like particle (VLP), by inserting three antigens (Spike, envelope and membrane) of SARS-CoV-2 into a highly characterized -based D-Crypt™ platform. Dot blot analysis was performed to confirm the presence of S, E, and M proteins in PRAK-03202. The number of particles in PRAK-03202 was measured using nanoparticle tracking analysis (NTA). The sensitivity of VLP-ELISA was evaluated in 100 COVID positive. PRAK-03202 was produced at a 5 L scale using fed-batch fermentation. Dot blot confirmed the presence of S, E, and M proteins in PRAK-03202. The number of particles in PRAK-03202 was 1.21 × 10 mL . In samples collected >14 days after symptom onset, the sensitivity, specificity, and accuracy of VLP-ELISA were 96%. We did not observe any significant differences in sensitivity, specificity, and accuracy when post-COVID-19 samples were used as negative controls compared to pre-COVID-samples. At a scale of 5 L, the total yield of PRAK-03202 was 100-120 mg/L. In conclusion, we have successfully developed an in-house VLP-ELISA to detect IgG antibodies against three antigens of SARS-CoV-2 as a simple and affordable alternative test.