Abstract
Objectives: Antiviral adaptive immunity involves memory B cells (MBC) and memory T cells (MTC). The dynamics of MBC and MTC in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) convalescents warrant further investigation.
Methods: In this cross-sectional and longitudinal study, blood-derived MBC and MTC responses were evaluated in 68 anti-spike IgG-positive mild coronavirus disease 2019 (COVID-19) convalescents at visit 1, between 1 and 7 months (median 4.1 months) after disease onset. SARS-CoV-2 anti-spike IgG was determined by ELISA, MBC by SARS-CoV-2-specific receptor binding domain (RBD) ELISpot, and interferon gamma (IFN-γ)-, interleukin 2 (IL2)-, and IFN-γ+IL2-secreting MTC by IFN-γ and IL2 SARS-CoV-2 FluoroSpot. For 24 patients sampled at the first visit, the IgG, MBC, and MTC analyses were also performed 3 months later at the second visit.
Results: Seventy-two percent of convalescents were both MBC- and MTC-positive, 18% were MBC-positive and MTC-negative, and 10% were MTC-positive and MBC-negative. The peak MBC response level was detected at 3 months after COVID-19 onset and persisted up to 7 months post infection. Significant MTC levels were detected 1 month after onset in response to S1, S2_N, and SNMO peptide pools. The frequency and magnitude of the MTC response to SNMO was higher than those to S1 and S2_N. Longitudinal analysis demonstrated that even when specific humoral immunity declined, the cellular immunity persisted.
Conclusions: The study findings demonstrate the durability of adaptive cellular immunity at least for 7 months after SARS-CoV-2 infection, suggesting long-lasting protection.
Keywords: Convalescents; IgG; Memory B cells; Memory T cells; SARS-CoV-2.
【저자키워드】 SARS-CoV-2, IgG, memory B cells, memory T cells, Convalescents, 【초록키워드】 COVID-19, coronavirus disease, SARS-CoV-2, Coronavirus disease 2019, coronavirus, adaptive, Immunity, T cells, cross-sectional, SARS-COV-2 infection, memory B cells, peptide, severe acute respiratory syndrome Coronavirus, ELISA, Receptor binding domain, Humoral immunity, interleukin, anti-Spike IgG, cellular immunity, longitudinal study, RBD, response, memory T cells, Patient, Mild, ELISPOT, respiratory, convalescent, longitudinal, memory T cell, Anti-spike, memory B cell, IFN-γ, MBC, longitudinal analysis, interferon gamma, Frequency, Analysis, disease onset, determined by, acute respiratory syndrome, first visit, acute respiratory syndrome coronavirus, acute respiratory syndrome coronavirus 2, peptide pools, post infection, interleukin 2, adaptive cellular immunity, SARS-CoV-2 anti-spike IgG, performed, evaluated, median, was determined, demonstrated, long-lasting, magnitude, Significant, IL2, declined, 【제목키워드】 SARS-CoV-2, T cell, Mild, profile, memory B, COVID-19 convalescent patient,