Pre-existing cross-reactive neutralizing activity against SARS-CoV-2 and seasonal coronaviruses prior to the COVID-19 pandemic (2014-2019) with limited immunity against recent emerging SARS-CoV-2 variants, Vietnam

• Published in: International journal of infectious diseases Vol. 139; pp. 109 - 117
• Main Authors: Nguyen, Thi Thanh Ngan, Choo, Ee Mei, Nakamura, Yukio, Suzuki, Ryuji, Shiina, Takashi, Shin-I, Tadasu, Fukuta, Mizuki, Nguyen, Co Thach, Nguyen, Thi Thu Thuy, Nguyen, Le Khanh Hang, Hoang, Vu Mai Phuong, Morita, Kouichi, Dang, Duc Anh, Hasebe, Futoshi, Le, Thi Quynh Mai, Moi, Meng Ling
• Format: Journal Article
• Language: English
• Published: Canada Elsevier 01.02.2024
• Subjects: Antibodies, Neutralizing; Antibodies, Viral; Cellular immunity; COVID-19; COVID-19 - epidemiology; COVID-19 Vaccines; Epitopes; Humans; Pandemics; Pre-existing antibodies; SARS-CoV-2 - genetics; Seasons; Spike Glycoprotein, Coronavirus - genetics; Variants of concern; Vietnam; Vietnam - epidemiology; Vietnam; COVID-19; Variants of concern; Vietnam; Cellular immunity; Pre-existing antibodies
• ISSN: 1201-9712; 1878-3511
• DOI: 10.1016/j.ijid.2023.11.008

SARS-CoV-2 transmission and epidemic potential is related to the population's immunity levels. As such, assessing different regions' preexisting immune responses to SARS-CoV-2 is important to understand the transmission potential of emerging SARS-CoV-2 variants. In 975 serum samples from Vietnam (2014 to 2019), anti-SARS-CoV-2 Immunoglobulin G levels were determined by enzyme-linked immunosorbent assay. Plaque reduction neutralization test (PRNT) was performed using Wuhan strain and variants of concern (VOCs). Cross-reactivity was confirmed by analyzing B-cell receptor (BCR) repertoire sequences and identifying BCR repertoire sequences-derived T-cell epitopes. Overall, 20.9% (n = 76/364) and 9.2% (n = 7) demonstrated SARS-CoV-2 neutralizing activity (PRNT ) against the Wuhan and Alpha strain, respectively. Neutralizing activity against Beta, Gamma, and Delta strains was absent (PRNT <5) in all samples. Cross-reactive epitopes against SARS-CoV-2 and other coronavirus spike proteins were detected in the N-terminal domain, S2, and receptor-binding domain regions. Following BCR and major histocompatibility complex analysis, T-cell receptor-recognized epitope motif (TREM) among pathogenic coronaviruses and coronaviruses spike proteins were the top TREM peptide, suggesting that pre-existing immunity against SARS-CoV-2 in Vietnam was due to exposure to common cold coronaviruses. With limited immunity against emerging VOCs, further monitoring, and control of the epidemic, along with COVID-19 vaccine programs against VOCs, are necessary.