Neutralising Antibodies After COVID-19
A research team from the Paul-Ehrlich-Institut, in collaboration with Frankfurt University Hospital, investigated the humoural immune response to SARS-CoV-2. The more severe the disease, the more neutralising antibodies the immune system produces.
COVID-19 can take very different courses: while some of those infected develop no symptoms, others become seriously ill. In almost 2% of confirmed cases in Germany, the disease is fatal. In order to develop effective therapeutic measures, it is first necessary to understand the pathogenesis of COVID-19 and the immunological processes that lead to the different courses of the disease.
The formation of antibodies against SARS-CoV-2 – the humoural immune response – can provide us with information about these relationships. Research teams from the Paul-Ehrlich-Institut led by Prof. Barbara Schnierle, head of the AIDS, New and Emerging Pathogens section, and Dr Heinrich Scheiblauer, deputy head of the in-vitro diagnostics testing laboratory, investigated this question together with scientists from the University Hospital of Frankfurt am Main and the Leibniz Institute for Primate Research. They characterised the humoural immune response of 143 COVID-19 patients and identified SARS-CoV-2-specific antibodies using enzyme-linked immunosorbent assay (ELISA). The neutralisation activity, i.e. the ability of the antibodies to prevent the infection of target cells, was analysed using pseudotyped lentiviral vectors – virus particles equipped with the spike protein of SARS-CoV-2.
A knowledge of the relationship between pathogenesis and immune response is a prerequisite for identifying possible correlates of protection for the development of vaccines and therapeutic antibodies.
Prof. Barbara Schnierle , Head of the AIDS, New and Emerging Pathogens Section
Around three quarters of the 143 COVID-19 patients experienced only mild illness. Clinically severe cases were, however, more common among the elderly patients. The more severe the disease, the more SARS-CoV-2 neutralising antibodies were found in the patients’ serum samples. The titres of the immunoglobulins (Ig) IgG and IgA correlated with the severity of the disease. In mild cases, the IgG antibody level declined significantly around 100 days after the onset of the disease. The low antibody titre after a mild case of COVID-19 explains why most plasma samples from recovered patients do not display a high neutralising activity.
Literature
Henss L, Scholz T, von Rhein C, Wieters I, Borgans F, Eberhardt FJ, Zacharowski K, Ciesek S, Rohde G, Vehreschild M, Stephan C, Wolf T, Hofmann-Winkler H, Scheiblauer H, Schnierle BS (2020): Analysis of humoral immune responses in SARS-CoV-2 infected patients.
J Infect Dis 223: 56-61.