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Monoclonal antibody (mAb) therapy is one of the most promising immunotherapies that have shown the potential to prevent or neutralize the effects of COVID-19 in patients at very early stages, with a few formulations recently approved by the European and American medicine agencies. However, a main bottleneck for their general implementation resides in the time-consuming, laborious, and highly-specialized techniques employed for the manufacturing and assessing of these therapies, excessively increasing their prices and delaying their administration to the patients. We propose a biomimetic nanoplasmonic biosensor as a novel analytical technique for the screening and evaluation of COVID-19 mAb therapies in a simpler, faster, and reliable manner. By creating an artificial cell membrane on the plasmonic sensor surface, our label-free sensing approach enables real-time monitoring of virus-cell interactions as well as direct analysis of antibody blocking effects in only 15 min assay time. We have achieved detection limits in the 102 TCID50/mL range for the study of SARS-CoV-2 viruses, which allows to perform neutralization assays by only employing a low-volume sample with common viral loads. We have demonstrated the accuracy of the biosensor for the evaluation of two different neutralizing antibodies targeting both Delta and Omicron variants of SARS-CoV-2, with half maximal inhibitory concentrations (IC50) determined in the ng/mL range. Our user-friendly and reliable technology could be employed in biomedical and pharmaceutical laboratories to accelerate, cheapen, and simplify the development of effective immunotherapies for COVID-19 and other serious infectious diseases or cancer.

Ljungan virus (LV), a Parechovirus of the Picornavirus family, first isolated from a bank vole at the Ljungan river in Sweden, has been implicated in the risk for autoimmune type 1 diabetes. An assay for neutralizing Ljungan virus antibodies (NLVA) was developed using the original 87-012 LV isolate. The goal was to determine NLVA titres in incident 0-18 years old newly diagnosed type 1 diabetes patients (n=67) and school children controls (n=292) from Jämtland county in Sweden. NLVA were found in 41 of 67 (61 %) patients compared to 127 of 292 (44 %) controls (P=0.009). In the type 1 diabetes patients, NLVA titres were associated with autoantibodies to glutamic acid decarboxylase (GADA) (P=0.023), but not to autoantibodies against insulin (IAA) or islet antigen-2 (IA-2A). The NLVA assay should prove useful for further investigations to determine levels of LV antibodies in patients and future studies to determine a possible role of LV in autoimmune type 1 diabetes., Erratum: Neutralizing Ljungan virus antibodies in children with newly diagnosed type 1 diabetes, Annika Lundstig, Sharla L. McDonald, Marlena Maziarz, William C. Weldon, Fariba Vaziri-Sani, Åke Lernmark and Anna-Lena Nilsson, Journal of General Virology 2021;102, doi: 10.1099/jgv.0.001602In the published version of this article, the second author’s name was listed incorrectly. The author’s name should have been listed as: ‘Sharla L. McDonald’.The Microbiology Society apologises for any inconvenience caused.Funding information:This study was supported by the:Stiftelsen Axel Tielmans MinnesfondPrinciple Award Recipient: Annika LundstigH.K.H. Kronprinsessan Lovisas Förening för Barnasjukvård (SE)Principle Award Recipient: Annika LundstigSven Mattssons Stiftelse Principle Award Recipient: Annika LundstigLunds Revisorer Principle Award Recipient: Annika LundstigLisa och Johan Grönbergs StiftelsePrinciple Award Recipient: Annika LundstigSydvästra Skånes Diabetesförening Principle Award Recipient: Annika Lundstig

We conducted a serologic survey of 2,430 serum samples collected during 1997-2012 for various studies to determine the prevalence of the hemorrhagic fever virus Ebola virus (EBOV) in equatorial Africa. We screened serum samples for neutralizing antibodies by using a pseudotype microneutralization assay and a newly developed luciferase immunoprecipitation system assay. Specimens seroreactive for EBOV were confirmed by using an ELISA. Our results suggest a serologic prevalence of 2%-3.5% in the Republic of the Congo and the Democratic Republic of the Congo, which have reported outbreaks of infection with EBOV. In addition we detected a seroprevalence of 1.3% in southern Cameroon, which indicated a low risk for exposure in this region.

[Background] In Ebola virus (EBOV) infection, the specific neutralizing activity of convalescent plasma against other members of the Ebolavirus genus has not been extensively analyzed. [Methods] We measured the neutralizing activity in plasma from 3 survivors of the recent outbreak due to the Makona variant of EBOV and tested its neutralizing potency against other variants of EBOV (ie, Mayinga and Kikwit) and against Sudan virus (SUDV), Bundibugyo virus (BDBV), and Reston virus (RESTV), using a glycoprotein (GP)–pseudotyped lentiviral system both with fulllength GP and in vitro–cleaved GP (GPCL). [Results] Convalescent plasma specimens from survivors of EBOV infection showed low neutralizing activity against full-length GPs of SUDV, BDBV, RESTV, and EBOV variants Mayinga and Kikwit. However, broad and potent neutralizing activity was observed against the GPCL forms of SUDV, BDBV, and RESTV. [Discussion] Removal of the mucin-like domain and glycan cap from the GP of members of the Ebolavirus genus presumably exposes conserved epitopes in or in the vicinity of the receptor binding site and internal fusion loop that are readily amenable to neutralization. These types of broad neutralizing antibodies could be induced by using immunogens mimicking GPCL.

It is confirmed that a short peptide, QLKLNWFKKGSS can elicit neutralizing antibodies in rabbits. The titer of the antibodies in neutralization was 1:320 for a 50% reduction. Attempt to express NS1 in mammalian cells was made using NS1 coding sequence cloned under the control of RSV promoter. No protein was detected by in vivo labeling and immunoprecipitation techniques. The same coding sequence of NS1 when transferred to a vaccinia-based expression system which produces both the mRNA and the protein in the cytoplasm, there was good expression of NS1, suggesting that there is no lethal mutation in the coding sequence of NS1. A long cDNA from nucleotide 7 to 4700 of DEN-2 genome was constructed.