POWER AND APPLICABILITY LIMITS OF METHODS FOR DETERMINATION OF INFLUENZA VIRUS HEMAGGLUTININ
Hemagglutinins (HA) of influenza virus are proteins that bind to sialic acid residues on the surface of host cells, promoting virus internalization. Study of possibilities to block these processes supports progress in development of antiviral drugs. Many factors determine «the state of HA» outside the virus: HA source and preparation method, posttrans-lational modifications, pH, etc. (the term «state» jointly means both tertiary structure and oligomerization degree of HA). Functional activity determined with the state of HA considerably affects the results acquired by different methods. This review analyzes the abilities and applicability limits of current assays regarding the state of HA.