HT, MK, KS, TS, MS, and YM wrote and edited the manuscript

HT, MK, KS, TS, MS, and YM wrote and edited the manuscript. collected from hospitalized patients with COVID-19, was also examined. As a result, the inhibition of pseudotyped computer virus contamination was specifically observed in both serum and whole blood and was also correlated with the results of the IFA. Conclusions In conclusion, the CRNT for COVID-19 is usually a convenient assay system that Tos-PEG4-NH-Boc can be performed in a BSL-2 laboratory with high specificity and sensitivity for evaluating the occurrence of neutralizing antibodies against SARS-CoV-2. Keywords: Pseudotyped computer virus, VSV, SARS-CoV-2, Neutralization assay, Serum, Whole blood Background Recently, the infectious Coronavirus Tos-PEG4-NH-Boc Disease 2019 (COVID-19) emerged and is caused by a newly identified coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) [1]. Globally, COVID-19 severely impacted health and socio-economic conditions. Currently, no safe and effective antivirals or other therapies for COVID-19 exist, although some drugs, such as remdesivir, showed limited efficacy for the treatment of patients with COVID-19 [2, 3]. Much like other diseases, proper treatment requires an accurate diagnosis. Therefore, establishing diagnostics, such as the detection of target viral genes and antibodies, is also required. The genome structure of SARS-CoV-2 is similar to that of severe acute respiratory syndrome coronavirus SARS-CoV, which is the causative agent for severe acute respiratory syndrome (SARS) that showed high mortality and morbidity in the late 2002-to the middle of 2003 outbreak, which mainly occurred in China [4]. The proteins of SARS-CoV-2 consist of Tos-PEG4-NH-Boc two large polyproteins: ORF1a and ORF1ab; four structural proteins: spike (S), envelope (E), membrane (M), and nucleocapsid (N); and eight accessory proteins: ORF3a, ORF3b, ORF6, ORF7a, ORF7b, ORF8a, ORF8b, and ORF9b. S protein is usually a glycoprotein, which is responsible for binding and penetration of target cells. The S Tos-PEG4-NH-Boc protein is also important for induction of protective humoral and cellular immunity during contamination. The S protein is the main target with which the neutralizing antibodies react. Measuring the SARS-CoV-2 neutralizing antibodies is important for proper diagnosis, to study the serological epidemiology and determine infection control of SARS-CoV-2. The enzyme-linked immunosorbent assay (ELISA), immunofluorescence assay (IFA), and immunochromatography utilize the principle of antigenCantibody reaction and were developed as serodiagnostic methods for SARS-CoV-2 infection. The specificity of these assays is fairly high, but problems are present such as relatively low sensitivity except for ELISA and a high rate of false positives. The neutralization antibody test (NT) for serum using live SARS-CoV-2 is a method in which inhibition of the serum upon viral infection is observed in the presence of neutralizing antibodies against proteins involved in viral binding and penetration in the serum. Generally, the NT is the standard method used to confirm the presence of neutralizing antibodies against SARS-CoV-2. However, this method takes a long time because it depends on the growth of the virus, and it is not a simple measuring system in terms of complicated handling and biosafety for highly pathogenic SARS-CoV-2. Therefore, recently, a pseudotyped virus system Rabbit Polyclonal to NRIP3 based on vesicular stomatitis virus (VSV) or pseudotyped particle systems based on lentivirus or retrovirus were developed for the detection of neutralizing antibodies instead of using infectious and authentic viruses [5C7]. Although a significant need exists to evaluate the neutralizing antibody against SARS-CoV-2 in the clinical setting as reported in recent papers [8C12], the ability to perform the NT under lower BSL laboratory conditions is preferred. In this study, an antibody detection system based on the chemiluminescence reduction neutralization test (CRNT) and using the truncated S protein-based pseudotyped viruses was developed. Truncated S protein-based pseudotyped viruses was highly infectious and easier to use for CRNT. The correlation between antibody titers against SARS-CoV-2 determined by CRNT were evaluated along with those determined by the IFA and ELISA in which recombinant S protein was used as an antigen. In addition, this study showed that CRNT can assess the presence of neutralizing antibodies even in Tos-PEG4-NH-Boc a small amount of whole blood. The usefulness of.