SARS-CoV-2 specific antibody and neutralization assays reveal the wide range of the humoral immune response to virus

Development of antibody protection during SARS-CoV-2 infection is a pressing question for public health and for vaccine development. We developed highly sensitive SARS-CoV-2-specific antibody and neutralization assays. SARS-CoV-2 Spike protein or Nucleocapsid protein specific IgG antibodies at titers more than 1:100,000 were detectable in all PCR+ subjects (n=115) and were absent in the negative controls. Other isotype antibodies (IgA, IgG1-4) were also detected. SARS-CoV-2 neutralization was determined in COVID-19 and convalescent plasma at up to 10,000-fold dilution, using Spike protein pseudotyped lentiviruses, which were also blocked by neutralizing antibodies (NAbs). Hospitalized patients had up to 3000-fold higher antibody and neutralization titers compared to outpatients or convalescent plasma donors. Interestingly, some COVID-19 patients also possessed NAbs against SARS-CoV Spike protein pseudovirus. Together these results demonstrate the high specificity and sensitivity of our assays, which may impact understanding the quality or duration of the antibody response during COVID-19 and in determining the effectiveness of potential vaccines. Using SARS-CoV-2-specific antibody- and neutralization assays, Dogan et al find that hospitalized individuals show higher IgG antibody responses and higher neutralization titers compared to outpatient or convalescent plasma donors, providing insights into the host humoral response to SARS CoV-2.

Automated summary

Development of highly sensitive SARS-CoV-2-specific antibody and neutralization assays revealed that hospitalized individuals have higher IgG antibody responses and neutralization titers compared to outpatient or convalescent plasma donors, providing insights into the host humoral response to SARS CoV-2.