Antigenically relevant amino acid positions as revealed by reactions of monoclonal antibodies with the nucleoproteins of closely related influenza A virus strains

The locations of amino acid positions relevant to antigenic variation in the nucleoprotein (NP) of influenza virus are not conclusively known. We analysed the antigenic structure of influenza A virus NP by introducing site-specific mutations at amino acid positions presumed to be relevant for the differentiation of strain differences by anti-NP monoclonal antibodies. Mutant proteins were expressed in a prokaryotic system and analysed by performing ELISA with monoclonal antibodies. Four amino acid residues were found to determine four different antibody-binding sites. When mapped in a 3D X-ray model of NP, the four antigenically relevant amino acid positions were found to be located in separate physical sites of the NP molecule.

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Antigenic characterization of influenza A virus matrix protein with monoclonal antibodies.

Journal of Virology ◽

10.1128/jvi.49.1.248-252.1984 ◽

1984 ◽

Vol 49 (1) ◽

pp. 248-252 ◽

Cited By ~ 26

Author(s):

K L van Wyke ◽

J W Yewdell ◽

L J Reck ◽

B R Murphy

Keyword(s):

Monoclonal Antibodies ◽

Influenza A Virus ◽

Influenza A ◽

Matrix Protein ◽

Antigenic Characterization

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Analysis of the Receptor Specificity of Influenza A Virus Strains Using the Method of Surface Plasmon Resonance

BIOPHYSICS ◽

10.1134/s0006350920020153 ◽

2020 ◽

Vol 65 (2) ◽

pp. 222-224

Author(s):

G. S. Onkhonova ◽

P. Yu. Torzhkova ◽

V. Yu. Marchenko ◽

S. V. Svyatchenko ◽

A. S. Gudymo ◽

...

Keyword(s):

Surface Plasmon Resonance ◽

Influenza A Virus ◽

Surface Plasmon ◽

Plasmon Resonance ◽

Influenza A ◽

Receptor Specificity ◽

Virus Strains

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QUALITATIVE DIFFERENCES IN THE ANTIGENIC COMPOSITION OF INFLUENZA A VIRUS STRAINS

Journal of Experimental Medicine ◽

10.1084/jem.79.6.633 ◽

1944 ◽

Vol 79 (6) ◽

pp. 633-647 ◽

Cited By ~ 18

Author(s):

William F. Friedewald

Keyword(s):

Influenza A Virus ◽

Influenza A ◽

Serum Antibody ◽

Allantoic Fluid ◽

Influenza B Virus ◽

Influenza B ◽

Red Cell ◽

Homologous Virus ◽

Cell Adsorption ◽

Virus Strains

A study of the PR8, Christie, Talmey, W.S., and swine strains of influenza A virus by means of antibody absorption tests revealed the following findings: 1. Serum antibody could be specifically absorbed with allantoic fluid containing influenza virus or, more effectively, with concentrated suspensions of virus obtained from allantoic fluid by high-speed centrifugation or by the red cell adsorption and elution technique. Normal allantoic fluid, or the centrifugalized sediment therefrom, failed to absorb antibodies. Influenza B virus (Lee) caused no detectable absorption of antibody from antisera directed against influenza A virus strains, but it specifically absorbed antibody from Lee antisera. 2. The neutralizing, agglutination-inhibiting, and complement-fixing anti-bodies in ferret antisera were completely absorbed only by the homologous virus strain, even though 2 absorptions were carried out with large amounts of heterologous virus strains. 3. PR8 virus appeared to have the broadest range of specific antigenic components for it completely absorbed the heterologous antibodies in Christie and W.S. antisera and left only those antibodies which reacted with the respective homologous strains. The other virus strains (Christie, Talmey, W.S., swine) were more specific in the absorption of heterologous antibodies and completely removed only those antibodies which reacted with the absorbing virus. 4. The absorption tests revealed a higher degree of specificity and individuality of the virus strains than the various cross reactions previously reported. The strain specificity of PR8 virus was equally manifest in absorption tests with ferret sera and with human sera following vaccination. 5. The amount of homologous antibody remaining in a PR8 ferret serum after absorption with PR8 virus, obtained by the red cell adsorption and elution method, varied inversely as the concentration of virus used for absorption. A given concentration of virus, however, absorbed a greater percentage of neutralizing antibodies than either agglutination-inhibiting or complement-fixing antibodies.

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Functional Analysis of PA Binding by Influenza A Virus PB1: Effects on Polymerase Activity and Viral Infectivity

Journal of Virology ◽

10.1128/jvi.75.17.8127-8136.2001 ◽

2001 ◽

Vol 75 (17) ◽

pp. 8127-8136 ◽

Cited By ~ 78

Author(s):

Daniel R. Perez ◽

Ruben O. Donis

Keyword(s):

Amino Acids ◽

Influenza Virus ◽

Amino Acid ◽

Viral Replication ◽

Influenza A Virus ◽

Influenza A ◽

Amino Acid Sequences ◽

Influenza Viruses ◽

Virus Growth ◽

Transcription And Replication

ABSTRACT Influenza A virus expresses three viral polymerase (P) subunits—PB1, PB2, and PA—all of which are essential for RNA and viral replication. The functions of P proteins in transcription and replication have been partially elucidated, yet some of these functions seem to be dependent on the formation of a heterotrimer for optimal viral RNA transcription and replication. Although it is conceivable that heterotrimer subunit interactions may allow a more efficient catalysis, direct evidence of their essentiality for viral replication is lacking. Biochemical studies addressing the molecular anatomy of the P complexes have revealed direct interactions between PB1 and PB2 as well as between PB1 and PA. Previous studies have shown that the N-terminal 48 amino acids of PB1, termed domain α, contain the residues required for binding PA. We report here the refined mapping of the amino acid sequences within this small region of PB1 that are indispensable for binding PA by deletion mutagenesis of PB1 in a two-hybrid assay. Subsequently, we used site-directed mutagenesis to identify the critical amino acid residues of PB1 for interaction with PA in vivo. The first 12 amino acids of PB1 were found to constitute the core of the interaction interface, thus narrowing the previous boundaries of domain α. The role of the minimal PB1 domain α in influenza virus gene expression and genome replication was subsequently analyzed by evaluating the activity of a set of PB1 mutants in a model reporter minigenome system. A strong correlation was observed between a functional PA binding site on PB1 and P activity. Influenza viruses bearing mutant PB1 genes were recovered using a plasmid-based influenza virus reverse genetics system. Interestingly, mutations that rendered PB1 unable to bind PA were either nonviable or severely growth impaired. These data are consistent with an essential role for the N terminus of PB1 in binding PA, P activity, and virus growth.

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