title: Effects of hemagglutinin amino acid substitutions in H9 influenza A virus escape mutants.
abstract: We assessed the pH optimum of fusion, HA thermostability, and in vitro replication kinetics of previously obtained influenza H9 escape mutants. The N198S mutation significantly increased the optimum pH of fusion. Four HA changes, S133N, T189A, N198D, and L226Q, were associated with a significant increase in HA thermostability compared to the wild-type virus. HA amino acid changes at positions 116, 133, 135, 157, 162, and 193 significantly decreased the replicative ability of H9 escape mutants in vitro. Monitoring of pleiotropic effects of the HA mutations found in H9 escape mutants is essential for accurate prediction of all possible outcomes of immune selection of H9 influenza A viruses.
authors: D. I. Ivanovsky Institute of Virology, Ministry of Health of the Russian Federation, 123098, Moscow, Russia.
authors: Irina A
authors: IA
authors: Rudneva
authors: D. I. Ivanovsky Institute of Virology, Ministry of Health of the Russian Federation, 123098, Moscow, Russia.
authors: Tatiana A
authors: TA
authors: Timofeeva
authors: D. I. Ivanovsky Institute of Virology, Ministry of Health of the Russian Federation, 123098, Moscow, Russia.
authors: Anna V
authors: AV
authors: Ignatieva
authors: D. I. Ivanovsky Institute of Virology, Ministry of Health of the Russian Federation, 123098, Moscow, Russia.
authors: Aleksandr A
authors: AA
authors: Shilov
authors: FDA CDER, 10903 New Hampshire Avenue, Silver Spring, MD, 20993, USA. Natalia.Ilyushina@fda.hhs.gov.
authors: Natalia A
authors: NA
authors: Ilyushina
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D001717:Birds; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000737:chemistry* / Q000235:genetics; D006863:Hydrogen-Ion Concentration; D057131:Immune Evasion; D009980:Influenza A virus / Q000276:immunology / Q000302:isolation & purification / Q000502:physiology*; D005585:Influenza in Birds / Q000821:virology*; D020125:Mutation, Missense; D055550:Protein Stability; D013696:Temperature; D019562:Viral Load; D053586:Virus Internalization; D014779:Virus Replication
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus