Breiman Adrien, Ruvoën-Clouet Nathalie, Deleers Marie, Beauvais Tiffany, Jouand Nicolas, Rocher Jézabel, Bovin Nicolai, Labarrière Nathalie, El Kenz Hanane, Le Pendu Jacques
Université de Nantes, INSERM, CRCINA, Nantes, France.
CHU de Nantes, Nantes, France.
Front Microbiol. 2021 Feb 11;12:641460. doi: 10.3389/fmicb.2021.641460. eCollection 2021.
Human serum contains large amounts of anti-carbohydrate antibodies, some of which may recognize epitopes on viral glycans. Here, we tested the hypothesis that such antibodies may confer protection against COVID-19 so that patients would be preferentially found among people with low amounts of specific anti-carbohydrate antibodies since individual repertoires vary considerably. After selecting glycan epitopes commonly represented in the human anti-carbohydrate antibody repertoire that may also be expressed on viral glycans, plasma levels of the corresponding antibodies were determined by ELISA in 88 SARS-CoV-2 infected individuals, including 13 asymptomatic, and in 82 non-infected controls. We observed that anti-Tn antibodies levels were significantly lower in patients as compared to non-infected individuals. This was not observed for any of the other tested carbohydrate epitopes, including anti-αGal antibodies used as a negative control since the epitope cannot be synthesized by humans. Owing to structural homologies with blood groups A and B antigens, we also observed that anti-Tn and anti-αGal antibodies levels were lower in blood group A and B, respectively. Analyses of correlations between anti-Tn and the other anti-carbohydrates tested revealed divergent patterns of correlations between patients and controls, suggesting qualitative differences in addition to the quantitative difference. Furthermore, anti-Tn levels correlated with anti-S protein levels in the patients' group, suggesting that anti-Tn might contribute to the development of the specific antiviral response. Overall, this first analysis allows to hypothesize that natural anti-Tn antibodies might be protective against COVID-19.
人血清中含有大量抗碳水化合物抗体，其中一些可能识别病毒聚糖上的表位。在此，我们检验了这样一种假设，即此类抗体可能赋予针对新冠病毒病的保护作用，以至于由于个体抗体库差异很大，在特定抗碳水化合物抗体含量低的人群中更易发现患者。在选择了人抗碳水化合物抗体库中常见且可能也在病毒聚糖上表达的聚糖表位后，通过酶联免疫吸附测定法（ELISA）测定了88名感染严重急性呼吸综合征冠状病毒2（SARS-CoV-2）的个体（包括13名无症状感染者）以及82名未感染对照个体中相应抗体的血浆水平。我们观察到，与未感染个体相比，患者体内的抗Tn抗体水平显著降低。对于任何其他测试的碳水化合物表位，包括用作阴性对照的抗αGal抗体（因为该表位不能由人类合成），均未观察到这种情况。由于与A、B血型抗原存在结构同源性，我们还观察到，抗Tn抗体水平在A型血个体中较低，抗αGal抗体水平在B型血个体中较低。对抗Tn抗体与其他测试的抗碳水化合物抗体之间的相关性分析显示，患者和对照之间的相关性模式不同，这表明除了数量差异外还存在质量差异。此外，在患者组中，抗Tn水平与抗S蛋白水平相关，这表明抗Tn可能有助于特异性抗病毒反应的发展。总体而言，这一初步分析使我们能够推测天然抗Tn抗体可能对新冠病毒病具有保护作用。
