We investigated immune responses against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among a group of convalescent, potential blood donors in Germany who had PCR-confirmed SARS-CoV-2 infection. Sixty days after onset of symptoms, 13/78 (17%) study participants had borderline or negative results to an ELISA detecting IgG against the S1 protein of SARS-CoV-2. We analyzed participants with PCR-confirmed infection who had strong antibody responses (ratio >3) as positive controls and participants without symptoms of SARS-CoV-2 infection and without household contact with infected patients as negative controls. Using interferon-γ ELISpot, we observed that 78% of PCR-positive volunteers with undetectable antibodies showed T cell immunity against SARS-CoV-2. We observed a similar frequency (80%) of T-cell immunity in convalescent donors with strong antibody responses but did not detect immunity in negative controls. We concluded that, in convalescent patients with undetectable SARS-CoV-2 IgG, immunity may be mediated through T cells.
【저자키워드】 COVID-19, coronavirus disease, severe acute respiratory syndrome coronavirus 2, viruses, respiratory infections, zoonoses, convalescent plasma, SARS-CoV-2, T cells, SARS, B cells, Severe acute respiratory syndrome, cellular immunity, ELISPOT, Seronegativity, PCR-confirmed infection, 【초록키워드】 IgG, coronavirus, immune response, Immunity, antibody, SARS-COV-2 infection, Antibody Response, Infection, ELISA, T cell, Germany, convalescent, SARS-CoV-2 IgG, convalescent patient, Donor, T-cell immunity, Frequency, Contact, blood donor, interferon-γ, acute respiratory syndrome, PCR-confirmed, negative controls, PCR-positive, participant, positive control, Volunteer, analyzed, detect, investigated, infected patient, the S1 protein, onset of symptoms, study participant, undetectable, without symptom, 【제목키워드】 IgG,