Influenza B Nucleoprotein [3E9/B2]

Influenza virus is a type of enveloped, segmented, negative-sense, single-stranded RNA virus of the Orthomyxoviridae family. There are three major antigenic types of influenza virus that are clinically relevant to humans, including Flu A, B and C. Flu A viruses affect humans and bird populations, whilst Flu B and C only infect humans. Based on the antigenicity of the glycoproteins, influenza A viruses are subdivided into sixteen H (H1-H16) and nine N (N1-N9) subtypes. The main antigenic determinants of influenza A and B viruses are the hemagglutinin (HA) and neuraminidase (NA) transmembrane glycoproteins. Projections of HA and NA cover the surface of the virus particle. NA forms a tetramer with an average molecular weight of 220 kDa (~55 kDa per monomer). The matrix (M) protein of influenza A virus is one of the two group-specific internal proteins of the virion, The non-structural protein (NP) exists as a homeodimer (molecular weight of 52 kDa) consisting of two identical monomers (each ~26 kDa). In healthy individuals, Influenza B causes a self-limiting respiratory illness. However, Influenza B can cause severe illness and hospitalization in the young, the elderly and high-risk patients. Effective vaccines are available for individuals at risk of developing severe disease, but must be developed and administered annually due to the rapidly-evolving nature of the virus. Quadrivalent vaccines that include two subtypes of Influenza A and B, are replacing trivalent vaccines in an attempt to provide greater protection against Influenza B viral infections.