Abstract: Provided are an antiviral agent and an antiviral food as novel methods for utilizing a Euglena-derived material. The antiviral agent and antiviral food, both comprising a Euglena-derived material as an active ingredient, are to be used for preventing or treating an infectious disease caused by an envelope-free RNA virus. Examples of the envelope-free RNA virus include rotaviruses belonging to Reoviridae. Examples of the Euglena-derived material include Euglena, a hot water extract of Euglena, paramylon and an alkali-treated paramylon.

Abstract: [Object] To provide an anti-human influenza virus antibody and an immunogenic artificial polypeptide. [Constitution] An anti-human influenza virus antibody which recognizes the stem regions of haemagglutinin molecules of the H1N1 and H2N2 subtypes and has a neutralization activity but does not recognize the stem region of the H3N2 subtype and has no neutralization activity. An immunogenic artificial polypeptide having an antigenicity substantially same as the stem regions of haemagglutinin molecules. An immunogenic artificial polypeptide having an antigenicity substantially same as the stem regions of haemagglutinin molecule and lacking the globular head region of haemagglutinin molecules. [Effect] This antibody is useful in the diagnosis and treatment of influenza A virus, while these polypeptides are useful as a vaccine.

Abstract: [Object] To provide an anti-human influenza virus antibody and an immunogenic artificial polypeptide.

Abstract: The invention provides an anti-human influenza virus antibody which recognizes the stem regions of haemagglutinin molecules of the H1N1 and H2N2 subtypes and has a neutralization activity but does not recognize the stem region of the H3N2 subtype and has no neutralization activity. Also provided is an immunogenic artificial polypeptide having an antigenicity substantially same as the stem region of haemagglutinin molecules, particularly lacking the globular head region of haemagglutinin molecules. This antibody is useful in the diagnosis and treatment of influenza A virus, while the polypeptides are useful as a vaccine.

Abstract: An anti-human influenza virus antibody is provided having the following characteristics: (a) specifically binds to the stem region of hemagglutinin of human influenza A virus subtype H3N2; (b) does not specifically bind to the stem region of hemagglutinin of human influenza A virus subtypes H1N1 and H2N2; and (c) does not specifically bind to the stem region of hemagglutinin of human influenza B virus. A composition comprising the antibody is also provided.

Abstract: An anti-human influenza virus antibody is provided which recognizes the stem regions of haemagglutinin molecules of the H1N1 and H2N2 subtypes and has a neutralization activity, but does not recognize the stem region of the H3N2 subtype and has no neutralization activity. Also provided is an immunogenic artificial polypeptide having an antigenicity substantially the same as the stem regions of haemagglutinin molecules. Provided further is an immunogenic artificial polypeptide having an antigenicity substantially the same as the stem regions of haemagglutinin molecule and lacking the globular head region of haemagglutinin molecules. The antibody is useful in the diagnosis and treatment of influenza A virus, while the polypeptides are useful as a vaccine.