Laboratorio de Investigacao Medica em Dermatologia e Imunodeficiencias (LIM 56), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, SP, BR.
Departamento de Virologia, Instituto Aggeu Magalhaes, Fundacao Oswaldo Cruz, Recife, PE, BR.
Clinics (Sao Paulo). 2021 Dec 6;76:e3548. doi: 10.6061/clinics/2021/e3548. eCollection 2021.
In this preliminary study we investigated cellular and humoral immune responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigens in blood samples from 14 recovered coronavirus disease 2019 (COVID-19) patients and compared them to those in samples from 12 uninfected/unvaccinated volunteers.
Cellular immunity was assessed by intracellular detection of IFN-γ in CD3+ T lymphocytes after stimulation with SARS-CoV-2 spike (S1), nucleocapsid (NC), or receptor-binding domain (RBD) recombinant proteins or overlapping peptide pools covering the sequence of SARS-CoV-2 spike, membrane and nucleocapsid regions. The humoral response was examined by ELISAs and/or chemiluminescence assays for the presence of serum IgG antibodies directed to SARS-CoV-2 proteins.
We observed differences between humoral and cellular immune profiles in response to stimulation with the same proteins. Assays of IgG antibodies directed to SARS-CoV-2 NC, RBD and S1/S2 recombinant proteins were able to differentiate convalescent from uninfected/unvaccinated groups. Cellular immune responses to SARS-CoV-2 protein stimuli did not exhibit a specific response, as T cells from both individuals with no history of contact with SARS-CoV-2 and from recovered donors were able to produce IFN-γ.
Determination of the cellular immune response to stimulation with a pool of SARS-CoV-2 peptides but not with SARS-CoV-2 proteins is able to distinguish convalescent individuals from unexposed individuals. Regarding the humoral immune response, the screening for serum IgG antibodies directed to SARS-CoV-2 proteins has been shown to be specific for the response of recovered individuals.
在这项初步研究中，我们调查了 14 例已康复的 2019 年冠状病毒病（COVID-19）患者血液样本中的严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）抗原的细胞和体液免疫反应，并将其与 12 例未感染/未接种疫苗的志愿者的样本进行了比较。
通过刺激 SARS-CoV-2 刺突（S1）、核衣壳（NC）或受体结合域（RBD）重组蛋白或覆盖 SARS-CoV-2 刺突、膜和核衣壳区序列的重叠肽池后，检测 CD3+T 淋巴细胞中 IFN-γ的细胞内表达来评估细胞免疫。通过 ELISA 和/或化学发光测定法检测针对 SARS-CoV-2 蛋白的血清 IgG 抗体的存在来检查体液反应。
我们观察到针对相同蛋白刺激的体液和细胞免疫谱之间存在差异。针对 SARS-CoV-2 NC、RBD 和 S1/S2 重组蛋白的 IgG 抗体检测能够区分恢复期和未感染/未接种疫苗组。针对 SARS-CoV-2 蛋白刺激的细胞免疫反应没有表现出特异性反应，因为没有 SARS-CoV-2 接触史的个体和康复供体的 T 细胞均能够产生 IFN-γ。
用 SARS-CoV-2 肽池而不是 SARS-CoV-2 蛋白刺激来确定细胞免疫反应能够将恢复期个体与未暴露个体区分开来。关于体液免疫反应，针对 SARS-CoV-2 蛋白的血清 IgG 抗体的筛选已被证明是针对康复个体的反应特异性的。
