Correlation between IgG titers and neutralizing activity.

<p>A, Correlation analysis of anti-2009 HA IgG and MN titers in 40 serum samples with IgG titers ≥1600. For reference, sera from 27 young adults immunized with inactivated 2009 H1N1 vaccine were included. Correlation between IgG and MN titers was calculated by square-coefficient correlation (R2). *N was stated beside data points. B, Correlation analysis of anti-seasonal H1N1 HA and neutralizing antibody titers in the general subjects (n = 40). The correlation between them was analyzed as described above.*N was stated beside data points. C, Correlation of titers of anti-2009 H1N1 and anti-seasonal H1N1 neutralizing antibodies in the general subjects (n = 40). *N was stated beside data points.