About Influenza B Hemagglutinin (HA) (B/Washington/02/2019, Victoria Lineage) Recombinant Protein

Influenza B virus is a major cause of seasonal influenza and contributes significantly to annual respiratory disease worldwide. Unlike influenza A viruses, influenza B viruses primarily infect humans and are divided into two antigenically distinct lineages: Victoria and Yamagata. The B/Washington/02/2019 (Victoria lineage) strain was selected by the World Health Organization (WHO) as a recommended vaccine strain for the 2020–2021 and 2021–2022 Northern Hemisphere influenza seasons, making it an important reference strain for vaccine production, antigenic surveillance, and influenza research.

The viral hemagglutinin (HA) glycoprotein is the major surface antigen of influenza B virus and is responsible for binding sialic acid-containing receptors on host epithelial cells, initiating viral entry through receptor-mediated endocytosis and membrane fusion. Because HA is the primary target of protective neutralizing antibodies and the principal antigen incorporated into seasonal influenza vaccines, recombinant HA proteins are widely used in vaccine research, serological assays, antibody characterization, and diagnostic development. eEnzyme's Influenza B Hemagglutinin (HA) (B/Washington/02/2019, Victoria Lineage) Recombinant Protein is expressed in HEK293 cells, providing native mammalian glycosylation and proper protein folding. The recombinant protein consists of amino acids 16–543 with a C-terminal 6×His tag, exhibits >95% purity, and is suitable for ELISA, Western blotting, hemagglutination inhibition (HI) assays, receptor-binding studies, structural biology, and diagnostic assay development.

Applications

Biological Significance of Influenza B Hemagglutinin

Hemagglutinin is the key viral glycoprotein responsible for initiating influenza infection by recognizing terminal sialic acid receptors on host cells and mediating low pH-induced membrane fusion within endosomes. As the dominant antigen exposed on the viral surface, HA elicits protective antibody responses and is the principal target of seasonal influenza vaccines. Continuous antigenic drift within the HA protein drives the emergence of new influenza variants, necessitating periodic updates of vaccine strains. The B/Washington/02/2019 (Victoria lineage) virus became an important vaccine reference strain because of its antigenic similarity to circulating Victoria-lineage viruses and has been widely used for vaccine potency testing, serological assays, and immunological studies.

The Influenza B Hemagglutinin (HA) (B/Washington/02/2019, Victoria Lineage) Recombinant Protein provides a high-quality research reagent for investigating influenza virus biology, evaluating vaccine-induced immune responses, screening therapeutic antibodies, and supporting the development of next-generation influenza vaccines, diagnostics, and antiviral therapeutics. Its mammalian expression system preserves native glycosylation and conformational epitopes, making it particularly valuable for immunological and structural studies.