Comparative study of hemagglutinin adsorption from influenza A H1N1, H3N2, and H5N1 strains on model surfaces using a...

Influenza A virus has caused multiple global pandemics throughout history, including the 1918 Spanish flu and the 2009 swine flu, and remains the primary cause of seasonal influenza worldwide, resulting in high infection rates and hundreds of thousands of deaths annually. Although transmission primarily occurs via close human-to-human contact through virus-containing aerosols, Influenza A can persist on various surfaces for prolonged periods, and transmission through contaminated surfaces is recognized as an additional route of infection. However, the processes governing how viral components interact with and adhere to surfaces remain insufficiently understood. To address this gap, we systematically investigated the adsorption behavior of hemagglutinin (HA), a surface glycoprotein of Influenza A, on various substrates under different temperature and pH conditions using a quartz crystal microbalance (QCM). HA derived from three strains, human H1N1, H3N2, and avian-origin H5N1, were compared. Distinct strain-dependent adsorption patterns were observed, with H3N2 HA exhibiting consistently higher adsorption affinity than H1N1 across multiple surfaces, aligning with the epidemiological predominance of H3N2. HA from H5N1 demonstrated the highest adsorption capacity on most functionalized surfaces; although H5N1 currently exhibits limited human-to-human transmission, its pronounced surface-binding propensity could represent an additional risk factor should adaptive mutations enhance transmissibility. Notably, adsorption was generally enhanced at pH 6 and 37 °C, emphasizing the conformational and functional compatibility of HA with physiologically relevant conditions. Overall, although isolated HA does not fully recapitulate whole-virion behavior, this work provides mechanistic insight into strain-dependent HA-surface interactions, and their potential implications for viral persistence and transmission dynamics.