Acid-induced conformational modification of the hemagglutinin molecule alters interaction of influenza virus with antigen-presenting cells

• Published in: The Journal of immunology (1950) Vol. 141; no. 6; pp. 1870 - 1876
• Main Authors: Eisenlohr, LC, Gerhard, W, Hackett, CJ
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Am Assoc Immnol 15-09-1988; American Association of Immunologists
• Subjects: Acetates; Antigen-Presenting Cells - immunology; Antigen-Presenting Cells - metabolism; Biological and medical sciences; Citrates; Epitopes - immunology; Fundamental and applied biological sciences. Psychology; Hemagglutinin Glycoproteins, Influenza Virus; Hemagglutinins, Viral - immunology; Hemagglutinins, Viral - metabolism; Hydrogen-Ion Concentration; Influenza A virus - immunology; Influenza A virus - metabolism; influenza virus; Kinetics; Membrane Glycoproteins - immunology; Membrane Glycoproteins - metabolism; Microbiology; Protein Conformation - drug effects; Replicative cycle, interference, host-virus relations, pathogenicity, miscellaneous strains; T-Lymphocytes - immunology; T-Lymphocytes - metabolism; Virology; Virus; Antigen; Influenzavirus A; Cell line; Hemagglutinin; PH; Orthomyxoviridae; Molecular interaction; Influenzavirus; Lymphocyte; Acid medium; Host virus relation
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.141.6.1870

Brief exposure of influenza virus to pH 5 was found to have extensive effects upon presentation of viral Th cell antigenic determinants. This acidity, comparable to that encountered in host cell endosomes, was known to effect conformational changes in the viral hemagglutinin (HA) which alter the molecule's fusion activity, antigenicity, and susceptibility to enzymes. Three major effects of low pH upon presentation of viral T cell determinants were observed: first, acid pretreatment permitted presentation by pre-fixed APC of two of three linear T cell sites of the HA molecule, bypassing the APC activity required to present untreated virus; second, the two determinants presented in this manner disappeared rapidly from APC surfaces; third, acid-pretreated virus was not efficiently utilized by active APC in the normal pathway of viral antigen presentation. These observations suggest that the pH-induced conformational transition of HA may constitute sufficient processing for certain linear determinants of the molecule and additionally influences the processes involved in the general formation and presentation of viral T cell sites.