Determination of the contents of two types of hemagglutinin B in quadrivalent influenza vaccines (split virion) by single radial immunodiffusion assay

Objective Quadrivalent influenza vaccines contain two lineages of type B virus, this study aimed to assess whether the result of single radial immunodiffusion (SRID) are accurate. The cross-interference of two type B hemagglutinins remains unknown. Methods We detected the vaccine samples developed by Jiangsu GDK Biological Technology Co., ltd by SRID. Results There was no significant difference between the HA content of antigen reagent, bulk sample and mixed sample of two B bulk within 10 to 40 μg/ml (P>0.05). Then each hemagglutinin B was diluted respectively by other three HA, 30 μg/ml, the other hemagglutinin B or phosphate buffer solution were measured within 10-160 μg/ml. Within 10-40 μg/ml, the HA content was proportional to the diameters of immunodiffusion (R2=0.998), while within the higher content range, a ternary linear regression equation fitted best (R2=0.999). Conclusions No cross-interference between B/Brisbane and B/Phuket was found in SRID within both detection ranges. Key words: Quadrivalent Influenza vaccine (split virion); B hemagglutinin content; Single radial immunodiffusion; Antigen; Linear regression