Patent ID: 7687611

Claim:
A method for quantifying the hemagglutinin (HA) titer of an influenza A or influenza B HA antigen preparation, the method comprising: separating hemagglutinin (HA) antigens from an influenza A or influenza B virus by a method comprising: obtaining a preparation comprising HA antigens from influenza A or influenza B virus; solubilizing the antigens by a detergent in a pH controlled solution; cleaving the HA antigens into HA1 and HA2 with a protease; reducing the HA1 and HA2 antigens with a reducing agent; derivatizing the HA1 and HA2 antigens with an alkylating agent; applying the antigen preparation on a Reversed-Phase High-Performance Liquid Chromatography (RP-HPLC) column; eluting HA1 and HA2 antigens from the RP-HPLC column with an ion pairing agent in an organic mobile phase, wherein elution is performed at a temperature of between approximately 50° C. and approximately 70° C., thereby separating HA1 from HA2; and measuring the peak area of eluted HA1 antigen in a chromatogram resulting from the elution to quantify the HA titer of the antigen preparation.