Neutralization of Different Variants of SARS-CoV-2 by a F(ab’)2 Preparation from Sera of Horses Immunized with the Viral Receptor Binding Domain

Le résumé fourni par la source

The Receptor Binding Domain (RBD) of SARS-CoV-2, the virus responsible for the COVID-19 pandemic, is the functional region of the viral Spike protein (S), which is involved in cell attachment to target cells. The virus has accumulated progressively mutations in its genome, particularly in the RBD region, many of them associated with immune evasion to the host neutralizing antibodies. Some of the viral lineages derived from this evolution, have been classified as Variant of Interest (VOI) or Concern (VOC). The neutralizing capacity of a F(ab’)2 preparation from sera of horses immunized with viral RBD was evaluated, by lytic plaque reduction assay, against different SARS-CoV-2 variants. A F(ab’)2 preparation of an hyperimmune serum with 15 immunizations with RBD, exhibited a high titer of neutralizing antibodies against the ancestral-like strain (1/18,528). A reduction in the title of the F(ab’)2 preparation was observed against the different variants tested. The highest reduction was observed for the Omicron VOC (4.7 fold), followed by the Mu VOI (2.6), Delta VOC (1.8 fold) and Gamma VOC (1.5). Even if a progressive reduction in the neutralizing antibodies titer against the different variants evaluated was observed, the serum still exhibited a significant neutralizing titer, against the Mu VOI and the Omicron VOC (1/7113 and 1/3918 respectively), the strains evaluated most resistant to neutralization.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.