tetano
Editor, Senior Moderator
J Virol Methods
. 2020 Nov 20;114025.
doi: 10.1016/j.jviromet.2020.114025. Online ahead of print.
Evaluating SARS-CoV-2 spike and nucleocapsid proteins as targets for antibody detection in severe and mild COVID-19 cases using a Luminex bead-based assay
Joachim Mari?n[SUP] 1 [/SUP], Ann Ceulemans[SUP] 2 [/SUP], Johan Michiels[SUP] 2 [/SUP], Leo Heyndrickx[SUP] 2 [/SUP], Karen Kerkhof[SUP] 2 [/SUP], Nikki Foque[SUP] 3 [/SUP], Marc-Alain Widdowson[SUP] 4 [/SUP], Laure Mortgat[SUP] 5 [/SUP], Els Duysburgh[SUP] 5 [/SUP], Isabelle Desombere[SUP] 6 [/SUP], Hilde Jansens[SUP] 7 [/SUP], Marjan Van Esbroeck[SUP] 3 [/SUP], Kevin K Ari?n[SUP] 8 [/SUP]
Affiliations
Abstract
Large-scale serosurveillance of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) will only be possible if serological tests are sufficiently reliable, rapid and affordable. Many assays are either labour-intensive and require specialised facilities (e.g. virus neutralization assays), or are expensive with suboptimal specificity (e.g. commercial ELISAs and RDTs). Bead-based assays offer a cost-effective alternative and allow for multiplexing to test for antibodies against multiple antigens and against other pathogens. Here, we compare the performance of spike (S) and nucleocapsid (NP) antigens for the detection of SARS-CoV-2 specific IgG, IgM and IgA antibodies in a panel of sera that includes recent (up to six weeks after symptom onset, severe n = 44; and mild cases n = 52) and old infections (five months after symptom onset, mild n = 104), using a Luminex-bead based assay and comparison to a virus neutralization test. While we show that neutralising antibody levels are significantly lower in mild than in severe cases, we demonstrate that a combination of the recombinant nucleocapsid protein (NP) and receptor-binding domain (RBD) results in highly specific (99%) IgG antibody detection five months after infection in 96% of cases. Although most severe Covid-19 cases developed a clear IgM and IgA response, titers fell below the detection threshold in more than 20% of mild cases in our bead-based assay. In conclusion, our data supports the use of RBD and NP for the development of SARS-CoV-2 serological IgG bead-based assays.
Keywords: Luminex antibody test; Sars-CoV-2; bead-based assay; serosurveillance; virus neutralization test.
. 2020 Nov 20;114025.
doi: 10.1016/j.jviromet.2020.114025. Online ahead of print.
Evaluating SARS-CoV-2 spike and nucleocapsid proteins as targets for antibody detection in severe and mild COVID-19 cases using a Luminex bead-based assay
Joachim Mari?n[SUP] 1 [/SUP], Ann Ceulemans[SUP] 2 [/SUP], Johan Michiels[SUP] 2 [/SUP], Leo Heyndrickx[SUP] 2 [/SUP], Karen Kerkhof[SUP] 2 [/SUP], Nikki Foque[SUP] 3 [/SUP], Marc-Alain Widdowson[SUP] 4 [/SUP], Laure Mortgat[SUP] 5 [/SUP], Els Duysburgh[SUP] 5 [/SUP], Isabelle Desombere[SUP] 6 [/SUP], Hilde Jansens[SUP] 7 [/SUP], Marjan Van Esbroeck[SUP] 3 [/SUP], Kevin K Ari?n[SUP] 8 [/SUP]
Affiliations
- PMID: 33227340
- DOI: 10.1016/j.jviromet.2020.114025
Abstract
Large-scale serosurveillance of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) will only be possible if serological tests are sufficiently reliable, rapid and affordable. Many assays are either labour-intensive and require specialised facilities (e.g. virus neutralization assays), or are expensive with suboptimal specificity (e.g. commercial ELISAs and RDTs). Bead-based assays offer a cost-effective alternative and allow for multiplexing to test for antibodies against multiple antigens and against other pathogens. Here, we compare the performance of spike (S) and nucleocapsid (NP) antigens for the detection of SARS-CoV-2 specific IgG, IgM and IgA antibodies in a panel of sera that includes recent (up to six weeks after symptom onset, severe n = 44; and mild cases n = 52) and old infections (five months after symptom onset, mild n = 104), using a Luminex-bead based assay and comparison to a virus neutralization test. While we show that neutralising antibody levels are significantly lower in mild than in severe cases, we demonstrate that a combination of the recombinant nucleocapsid protein (NP) and receptor-binding domain (RBD) results in highly specific (99%) IgG antibody detection five months after infection in 96% of cases. Although most severe Covid-19 cases developed a clear IgM and IgA response, titers fell below the detection threshold in more than 20% of mild cases in our bead-based assay. In conclusion, our data supports the use of RBD and NP for the development of SARS-CoV-2 serological IgG bead-based assays.
Keywords: Luminex antibody test; Sars-CoV-2; bead-based assay; serosurveillance; virus neutralization test.