RESUMO
Serological testing is essential to curb the consequences of the COVID-19 pandemic. However, most assays are still limited to single analytes and samples collected within healthcare. Thus, we establish a multianalyte and multiplexed approach to reliably profile IgG and IgM levels against several versions of SARS-CoV-2 proteins (S, RBD, N) in home-sampled dried blood spots (DBS). We analyse DBS collected during spring of 2020 from 878 random and undiagnosed individuals from the population in Stockholm, Sweden, and use classification approaches to estimate an accumulated seroprevalence of 12.5% (95% CI: 10.3%-14.7%). This includes 5.4% of the samples being IgG+IgM+ against several SARS-CoV-2 proteins, as well as 2.1% being IgG-IgM+ and 5.0% being IgG+IgM- for the virus' S protein. Subjects classified as IgG+ for several SARS-CoV-2 proteins report influenza-like symptoms more frequently than those being IgG+ for only the S protein (OR = 6.1; p < 0.001). Among all seropositive cases, 30% are asymptomatic. Our strategy enables an accurate individual-level and multiplexed assessment of antibodies in home-sampled blood, assisting our understanding about the undiagnosed seroprevalence and diversity of the immune response against the coronavirus.
Assuntos
Coleta de Amostras Sanguíneas/métodos , Teste Sorológico para COVID-19/métodos , COVID-19/imunologia , Imunidade Humoral , Adulto , Idoso , Anticorpos Antivirais/imunologia , COVID-19/etiologia , Teste em Amostras de Sangue Seco , Feminino , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Masculino , Pessoa de Meia-Idade , SARS-CoV-2/imunologia , Suécia , Adulto JovemRESUMO
With the increasing availability of collections of antibodies, their evaluation in terms of binding selectivity becomes an important but challenging task. Planar antigen microarrays are very suitable tools to address this task and provide a powerful proteomics platform for the characterization of the binding selectivity of antibodies toward thousands of antigens in parallel. In this chapter, we describe our in-house developed procedures for the generation of high-density planar antigen microarrays with over 21,000 features. We also provide the details of the assay protocol, which we routinely use for the assessment of binding selectivity of the polyclonal antibodies generated within the Human Protein Atlas.