Highlights • A swine influenza virus H3N2 subtype was isolated during epidemiological survey. • It is a complex and novel reassortant , and acquired accumulation of adaptive mutations. • Both rescue and parent strains demonstrated efficient replication in mammalian cells. • Key residues of the H3N2 HA collectively enhance the binding preference for human-type receptor. • The rescued H3N2 cause significant pulmonary pathological damage in mice. Abstract Pigs serve as key "mixing vessels" for influenza A viruses, playing a critical role in cross-species transmission , while the H3N2 subtype represents an important lineage within the swine influenza virus (SIV) family. In this study, a novel reassortant H3N2 SIV strain , designated A/Swine/Jiangsu/YZ07/2024 , was isolated from pigs exhibiting clinical symptoms in Northern Jiangsu , China during epidemiological survey . Genetic analysis revealed that the virus is a complex reassortant, with the internal ...
Abstract Nipah virus is a highly pathogenic virus in the family Paramyxoviridae that utilizes two distinct surface glycoproteins to infect cells . The receptor-binding protein (RBP) binds host receptors whereas the fusion protein (F) merges viral and host membranes . Here, we use nonreplicative pseudoviruses to safely measure the effects of all F single amino acid residue mutations on its cell entry function and neutralization by monoclonal antibodies . We compare mutational tolerance in F with previous experimental measurements for RBP and show that F is much more functionally constrained than the RBP . We also identify mutationally intolerant sites on the F trimer surface and core that are critical for proper function, and describe mutations that are candidates for stabilizing F in the prefusion conformation for vaccine design . We quantify how F mutations affect neutralization by six monoclonal antibodies, and show that the magnitude of mutational effects on neutralization var...