Radioligand Assay-Based Detection of Antibodies against SARS-CoV-2 in Hospital Workers Treating Patients with Severe COVID-19 in Japan

This study aimed to clarify whether infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is prevalent among the staff of a hospital providing treatment to patients with severe coronavirus disease 2019 (COVID-19) using radioligand assay (RLA). One thousand samples from the staff of a general hospital providing treatment to patients with severe COVID-19 were assayed for SARS-CoV-2 nucleocapsid protein (N) IgG using RLA. Nine patients with COVID-19 who had been treated in inpatient settings and had already recovered were used as control subjects, and 186 blood donor samples obtained more than 10 years ago were used as negative controls. Four of the 1000 samples showed apparently positive results, and approximately 10 or more samples showed slightly high counts. Interestingly, a few among the blood donor samples also showed slightly high values. To validate the results, antibody examinations using ELISA and neutralizing antibody tests were performed on 21 samples, and chemiluminescence immunoassay (CLIA) was performed on 201 samples, both resulting in a very high correlation. One blood donor sample showed slightly positive results in both RLA and CLIA, suggesting a cross-reaction. This study showed that five months after the pandemic began in Japan, the staff of a general hospital with a tertiary emergency medical facility had an extremely low seroprevalence of the antibodies against SARS-CoV-2. Further investigation will be needed to determine whether the slightly high results were due to cross-reactions or a low titer of anti-SARS-CoV-2 antibodies. The quantitative RLA was considered sensitive enough to detect low titers of antibodies.

Estimation of dose-response curves and identification of peaks in hormone pulsations: classic marriages of statistics to science

This essay examines the historical significance of two APS classic papers that are freely available online: De Léan A, Munson PJ, and Rodbard D. Simultaneous analysis of families of sigmoidal curves: application to bioassay, radioligand assay, and physiological dose-response curves. Am J Physiol Endocrinol Metab Gastrointest Physiol 235: E97–E102, 1978 ( http://ajplegacy.physiology.org/cgi/reprint/235/2/E97 ). Merriam GR and Wachter KW.Algorithms for the study of episodic hormone secretion. Am J Physiol Endocrinol Metab 243: E310–E318, 1982 ( http://ajplegacy.physiology.org/cgi/reprint/243/4/E310 ).

Detection by Radioligand Assay of Antibodies against Borna Disease Virus in Patients with Various Psychiatric Disorders

ABSTRACT Using a radioligand assay, which preserves the natural form of the antigen, antibodies against Borna disease virus nucleoprotein and phosphoprotein were detected in 11 and 19 sera of 171 psychiatric patients, respectively. Compared with results by Western blotting, three and nine sera were concordantly positive, respectively. The four sera showing the highest levels of antibodies by radioligand assay were all negative by Western blotting; however, dilution and inhibition tests supported the positive results. Our results suggest the importance of conformational structure to detect human anti-Borna disease virus antibodies.