Structural and functional characterization of the #antigenicity of #influenza A virus #hemagglutinin subtype #H15

Mapping Genetic Markers Associated with Antigenicity and Host Range in H9N2 Influenza A Viruses Infecting Poultry in Pakistan - PubMed

The aim of the current study was to map the genetic diversity in the haemagglutinin (HA) glycoprotein of influenza A viruses (IAVs) of the H9N2 subtype. Twenty-five H9N2 IAVs were isolated from broiler chickens from March to July 2019. The HA gene was amplified, and phylogenetic analysis was perform …

Antigenicity and receptor affinity of SARS-CoV-2 BA.2.86 spike - Nature

A SARS-CoV-2 Omicron subvariant, BA.2.86, has emerged and spread to numerous countries worldwide, raising alarm because its spike protein contains 34 additional mutations compared to its BA.2 predecessor1. We examined its antigenicity using human sera and monoclonal antibodies (mAbs). Reassuringly, BA.2.86 was not more resistant to human sera than the currently dominant XBB.1.5 and EG.5.1, indicating that the new subvariant would not have a growth advantage in this regard. Importantly, sera from patients who had XBB breakthrough infection exhibited robust neutralizing activity against all viruses tested, suggesting that upcoming XBB.1.5 monovalent vaccines could confer added protection. While BA.2.86 showed greater resistance to mAbs to subdomain 1 (SD1) and receptor-binding domain (RBD) class 2 and 3 epitopes, it was more sensitive to mAbs to class 1 and 4/1 epitopes in the “inner face” of RBD that is exposed only when this domain is in the “up” position. We also identified six new spike mutations that mediate antibody resistance, including E554K that threatens SD1 mAbs in clinical development. The BA.2.86 spike also had a remarkably high receptor affinity. The ultimate trajectory of this new SARS-CoV-2 variant will soon be revealed by continuing surveillance, but its worldwide spread is worrisome.