VOC 202012/01 Variant Is Effectively Neutralized by Antibodies Produced by Patients Infected before Its Diffusion in Italy

Abstract

The coronavirus disease 2019 (Covid-19) pandemic is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and presents a global health emergency that needs urgent intervention. Viruses constantly change through mutation, and new variants of a virus are expected to occur over time. In the United Kingdom (UK), a new variant called B.1.1.7 has emerged with an unusually large number of mutations. The aim of this study is to evaluate the level of protection of sera from 12 patients infected and later healed in Apulia Region (Italy) with Covid-19 between March and November 2020, when the English variant was not circulating in this territory yet, against the new VOC 202012/01 variant by seroneutralization assay. The sera of patients had already been tested before, using a virus belonging to the lineage B.1 and showed an antibody neutralizing titer ranging between 1:160 and 1:320. All the 12 sera donors confirmed the same titers of neutralizing antibodies obtained with a strain belonging to the lineage B.1.1.7 (VOC 202012/01). These data indicate that antibodies produced in subjects infected with variants of Sars-CoV-2 strain before the appearance of the English one, seem to have a neutralizing power also against this variant.

Outbreak of SARS-CoV-2 Lineage 20I/501Y.V1 in a Nursing Home Underlines the Crucial Role of Vaccination in Both Residents and Staff

“…The SARS-CoV-2 lineage 20I/501Y.V1 seems to be covered by the available vaccines. A recent Italian study by Rondinone et al [32] has indicated a high level of cross-lineage reactivity between the previously circulating strains and 20I/501Y.V1 lineage. In particular, all tested samples from the previously infected patients (n = 12) developed neutralizing antibody titers of 1:160-1:320 against the novel 20I/501Y.V1 lineage and these latter were the same as those against the previously circulating variant.…”

Identification of Human SARS-CoV-2 Monoclonal Antibodies from Convalescent Patients Using EBV Immortalization

“…The purified mAbs showed a spike S1/S2 binding activity of 103 and 81 AU/mL at a 1:2 dilution in the diasorin test. They were then tested by microneutralization assay, using three different Italian SARS-CoV-2 viral isolates belonging to Clades G and O and the lineage B1.1.7 U.K. [ 14 ]. The two anti-spike mAbs did not show any measurable neutralizing activity even at the highest concentration tested of 0.5 mg/mL.…”

“…The purified mAbs were tested for neutralization using three virus strains: Clade G VR10734 (S-D614G mutant, hCoV-19/Italy/LOM-INMI-10734/2020; GISAID Accession ID: EPI_ISL_568579), Clade O (2019-nCoV/Italy-INMI1; GISAID accession ID EPI_ISL_410546), and VOC 202012/01 (hCoV-19/Italy/CAM-INMI-118/2020; GISAID Accession ID: EPI_ISL_736997; Lineage B1.1.7) with serial dilution of purified antibody from the two positive clones (0.5 mg/mL to 0.5 ng/mL) according to published procedures [ 14 ]. Briefly, mAbs were diluted in serum-free medium and titrated in duplicate in ten-fold dilutions.…”

“…Equal volumes of 100 TCID 50 /well of each virus strain and mAbs dilutions were mixed and incubated at 37 °C for 30′ and then added to sub-confluent Vero E6 cells and incubated at 37 °C and 5% CO 2 . Seroneutralization was measured after 72 h incubation, based on the cytopathic effect observed in an inverted microscope [ 14 ]. Serum from the National Institute for Biological Standards and Control, U.K. (NIBSC) with known neutralization titer was used as a reference in the microneutralization assay (Research reagent for anti-SARS-CoV-2 Ab NIBSC code 20/130).…”

Detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a fourplex real-time quantitative reverse transcription-PCR assays

“…Since the beginning of the COVID-19 pandemic, several studies have reported genomic sequence variations of SARS-CoV-2 isolates (Leung et al 2021;Martin et al 2021;Rondinone et al 2021;Tegally et al 2021a;Tegally et al 2021b). Among these genetic variations, a single nucleotide polymorphism (SNP) found at position 8,782 (in orf1ab; C instead of T) of SARS-CoV-2 genomic sequence is a hallmark of the L strain (Tang et al 2020), whereas the unaltered nucleotide is found at the same position in the S strain.…”