Poster Presentation 8th Australasian Vaccines & Immunotherapeutics Development Meeting 2020

Sensitive detection of total anti-Spike antibodies and isotype switching in asymptomatic and symptomatic COVID-19 patients (#317)

Yun Shan Goh 1 2 , Jean-Marc Chavatte 3 , Alicia Lim 3 , Bernett Lee 2 , Siti Naqiah Amrun 1 2 , Cheryl Yi-Pin Lee 1 2 , Rhonda Sin-Ling Chee 1 2 , Bei Wang 2 , Chia Yin Lee 2 , Eve Zhi Xian Ngoh 2 , Cheng-I Wang 2 , Barnaby Edward Young 3 4 5 , Paul A Tambyah 3 6 , Shirin Kalimuddin 7 8 , Surinder Pada 9 , Seow-Yen Tan 10 , Louisa Jin Sun 11 , Mark I-Cheng Chen 3 12 , Yee-Sin Leo 3 4 5 13 , David C Lye 3 4 5 13 , Lisa FP Ng 1 2 14 15 16 17 , Raymond Tzer Pin Lin 3 13 , Laurent Renia 1 2 17
  1. Infectious Diseases Horizontal Technology Centre, Singapore, 8A BIOMEDICAL GROVE, #04-06 IMMUNOS BUILDING, SINGAPORE 138648
  2. Singapore Immunology Network, Singapore
  3. National Centre for Infectious Diseases, Singapore
  4. Department of Infectious Diseases, Tan Tock Seng Hospital, Singapore
  5. Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
  6. Department of Medicine, National University Hospital, Singapore
  7. Department of Infectious Diseases, Singapore General Hospital, Singapore
  8. Emerging Infectious Disease Program, Duke-NUS Medical School, Singapore
  9. Division of Infectious Diseases, Ng Teng Fong Hospital, Singapore
  10. Department of Infectious Diseases, Changi General Hospital, Singapore
  11. Alexandra Hospital, Singapore
  12. Saw Swee Hock School of Public Health, National University of Singapore and National University Health System,, Singapore
  13. Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore
  14. Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
  15. National Institute of Health Research, Health Protection Research Unit in Emerging and Zoonotic Infections, University of Liverpool, Liverpool
  16. Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool
  17. Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore

Early detection of infections is crucial to limit the spread of coronavirus 2019 disease (COVID-19). Here, we developed a flow cytometry-based assay to detect SARS-CoV-2 Spike protein (S protein) antibodies in COVID-19 patients. The assay detected specific IgM and IgG in COVID-19 patients and also the acquisition of all IgG subclasses, with IgG1 being the most dominant. The antibody response was significantly higher at a later stage of the infection. Furthermore, asymptomatic COVID-19 patients also developed specific IgM and IgG, with IgG1 as the most dominant subclass. Although the antibody levels were lower in asymptomatic infections, the assay was highly sensitive and detected 97% of asymptomatic infections. These findings demonstrated that the assay could be used for serological analysis of symptomatic patients, and also as a sensitive tool to detect asymptomatic infections, which may go undetected.