Evaluation of SARS-CoV-2 neutralizing antibodies using a vesicular stomatitis virus possessing SARS-CoV-2 spike protein

SARS-CoV-2 is a novel coronavirus that emerged in 2019 and is now classified in the genus Coronavirus with closely related SARS-CoV. SARS-CoV-2 is highly pathogenic in humans and is classified as a biosafety level (BSL)-3 pathogen, which makes manipulating it relatively difficult due to its infectious nature. To circumvent the need for BSL-3 laboratories, an alternative assay was developed that avoids live virus and instead uses a recombinant VSV expressing luciferase and possesses the full length or truncated spike proteins of SARS-CoV-2. Furthermore, to measure SARS-CoV-2 neutralizing antibodies under BSL2 conditions, a chemiluminescence reduction neutralization test (CRNT) for SARS-CoV-2 was developed. The neutralization values of the serum samples collected from hospitalized patients with COVID-19 or SARS-CoV-2 PCR-negative donors against the pseudotyped virus infection evaluated by the CRNT were compared with antibody titers determined from an immunofluorescence assay (IFA). The CRNT, which used whole blood collected from hospitalized patients with COVID-19, was also examined. As a result, the inhibition of pseudotyped virus infection was specifically observed in both serum and whole blood and was also correlated with the results of the IFA. In conclusion, the CRNT for COVID-19 is a convenient assay system that can be performed in a BSL-2 laboratory with high specificity and sensitivity for evaluating the occurrence of neutralizing antibodies against SARS-CoV-2.

Multidrug treatment with nelfinavir and cepharanthine against COVID-19

Antiviral treatments targeting the emerging coronavirus disease 2019 (COVID-19) are urgently required. We screened a panel of already-approved drugs in a cell culture model of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and identified two new antiviral agents: the HIV protease inhibitor Nelfinavir and the anti-inflammatory drug Cepharanthine. In silico modeling shows Nelfinavir binds the SARS-CoV-2 main protease consistent with its inhibition of viral replication, whilst Cepharanthine inhibits viral attachment and entry into cells. Consistent with their different modes of action, in vitro assays highlight a synergistic effect of this combined treatment to limit SARS-CoV-2 proliferation. Mathematical modeling in vitro antiviral activity coupled with the known pharmacokinetics for these drugs predicts that Nelfinavir will facilitate viral clearance. Combining Nelfinavir/Cepharanthine enhanced their predicted efficacy to control viral proliferation, to ameliorate both the progression of disease and risk of transmission. In summary, this study identifies a new multidrug combination treatment for COVID-19.

Crimean-Congo hemorrhagic fever.

Crimean-Congo hemorrhagic fever (CCHF), caused by infection with CCHF virus (CCHFV), is viral hemorrhagic fever with high case fatality rate. CCHFV is classified to Family Bunyaviridae, Genus Nairovirus. CCHF is endemic to Africa, Eastern Europe, the Middle East, central Asia, and southern Asia. CCHFV is maintained in nature in several spe- cies of ticks (Hyalomma and Ixodes species) and mammals. Humans are infected with CCHFV by tick-bite or direct contact with viremic animals such as sheep. The CCHF-endemic re- gions are relatively economically disadvantaged areas, therefore CCHF is considered to be one of the neglected infectious diseases. The pathophysiology has not yet been clarified fully. It is necessary to clarify the pathophysiology of CCHF and to develop specific antiviral drug- based therapy and vaccines, which might be effective in confering protection against CCHFV infections in the near future, because CCHF outbreaks continue to occur in the endemic re- gions.

Molecular epidemiology of Xinjiang hemorrhagic fever viruses / 中华实验和临床病毒学杂志

<p><b>BACKGROUND</b>To study the molecular biology of Xinjiang hemorrhagic fever (XHF) viruses, to explore its relationship with other Crimean-Congo hemorrhagic fever viruses, analyzing the epidemic origin and the tendency of geographic distribution of XHF.</p><p><b>METHODS</b>The S partial segment from the patient and tick samples collected in 2001 and 2002 was tested by RT-PCR, the positive samples were sequenced directly. The nucleotide homology of S partial segment as well as the whole segments were analyzed and the phylogenetic tree of S and M gene segments was drawn by computer.</p><p><b>RESULTS</b>All compared sequences of S partial segments from the patient and tick samples showed a high homology of nucleotide sequences. Phylogenetic tree divided all the analyzed viruses into three groups; Europe, African and Asian group. The Asian group can be divided further into another two branches: the middle Asian branch and the Chinese branch. All the Chinese isolates were clustered into one single group and was easy to be discriminated from the other isolates. The dividing of M segments seemed not completely related to the geographic origin of the viruses.</p><p><b>CONCLUSION</b>M segment classification was not consistent to the geographic distribution of the viruses. S segments analysis showed the close relationship of genetic background between the patient isolates and the tick isolates. Besides, all the Chinese isolates have the common evolution route and the gene structure characteristics displayed the regional distribution pattern.</p>

Serologic studies of Xinjiang hemorrhagic fever in Bachu county, 2001 / 中华流行病学杂志

<p><b>OBJECTIVE</b>To investigate the situation of Xinjiang hemorrhagic fever (XHF) in patients who have been diagnosed as XHF by clinical methods and to predict the condition in people who were liable to infection and in the host-animals.</p><p><b>METHODS</b>Sera collected from XHF patients and some peasants under the risk of contracting the disease, followed by checking the specific antibody against XHF with IgG-ELISA and IgM capture ELISA, and XHF viral antigen with antigen capture ELISA. In addition, 80 sheep/goats serums were collected from two places where there were more XHF cases and specific IgG antibody against XHF checked by ELISA method.</p><p><b>RESULTS</b>Positive rate of IgG and IgM antibodies were 39.62% (21/53) and 20.75% (11/53) respectively in the serums of patients; one patient's serum showed XHFV antigen positive by antigen capture ELISA. IgG antibody positive rate for peasants' sera was 21.05% (4/19), but IgM antibody detection showed negative for all sera. In sera from 80 sheep and goats, 70% (56/80) showed IgG positive.</p><p><b>CONCLUSION</b>Results showed that XHF broke out in Bachu county from April to June 2001 while recessive infection of the disease remained serious.</p>