The humoral immunity after SARS-CoV-2 infection or vaccination was examined. Convalescent sera after infection with variants of concern (VOCs: B.1.1.7, n = 10; B.1.351, n = 1) and sera from 100 vaccinees (Pfizer/BioNTech, BNT162b2, n = 33; Moderna, mRNA-1273, n = 11; AstraZeneca, ChAdOx1 nCoV-19/AZD1222, n = 56) were tested for the presence of immunoglobulin G (IgG) directed against the viral spike (S)-protein, its receptor-binding domain (RBD), the nucleoprotein (N) and for virus-neutralizing antibodies (VNA). For the latter, surrogate assays (sVNT) and a Vero-cell based neutralization test (cVNT) were used. Maturity of IgG was determined by measuring the avidity in an immunoblot (IB). Past VOC infection resulted in a broad reactivity of anti-S IgG (100%), anti-RBD IgG (100%), and anti-N IgG (91%), while latter were absent in 99% of vaccinees. Starting approximately two weeks after the first vaccine dose, anti-S IgG (75–100%) and particularly anti-RBD IgG (98–100%) were detectable. After the second dose, their titers increased and were higher than in the convalescents. The sVNT showed evidence of VNA in 91% of convalescents and in 80–100%/100% after first/second vaccine dose, respectively. After the second dose, an increase in VNA titer and IgGs of high avidity were demonstrated by cVNT and IB, respectively. Re-vaccination contributes to a more robust immune response.
【저자키워드】 COVID-19, IgG, vaccination, titer, humoral immune response, virus variants, avidity, virus-neutralizing antibodies, 【초록키워드】 immune response, VoC, B.1.351, mRNA-1273, neutralization, SARS-COV-2 infection, Infection, variants of concern, vaccine dose, BNT162b2, Humoral immunity, Immunoglobulin, B.1.1.7, RBD, sera, convalescent, ChAdOx1, AstraZeneca, cVNT, Moderna, anti-N IgG, anti-S IgG, Pfizer/BioNTech, Evidence, Anti-RBD IgG, second dose, sVNT, domain, viral spike, vaccinees, Maturity, starting, immunoblot, virus-neutralizing antibody, vaccinee, robust, tested, examined, detectable, was determined, were used, contribute, demonstrated, increase in, reactivity, 【제목키워드】 SARS-CoV-2, concern, development, Specific,