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. Author manuscript; available in PMC: 2014 Jul 10.
Published in final edited form as: Sci Transl Med. 2013 Aug 14;5(198):198ra107. doi: 10.1126/scitranslmed.3006637

Figure 3. HAI and IgG endpoint titers against seasonal H1N1 and H3N2 IAV strains over a 20 year period.

Figure 3

HAI titers were evaluated using 40 matched serum samples against A) Texas/91 H1N1 virus or B) Ala/81 H3N2 virus. Black hatched lines indicate an HAI titer of 40, which is the conventional cutoff used to indicate seroconversion to a given HA. GMTs are depicted by red lines IgG endpoint titers from the same sera were evaluated by ELISA against recombinant C) Texas/91 HA or D) Ala/81 HA, with GMTs depicted by orange lines. Data were compared using one-way repeated measures ANOVA. GMTs between exams were then compared using Tukey's multiple comparisons test. Statistically significant differences relative to exam 1 are indicated by asterisks. n.s. = not significant. Ratios of IgG endpoint titers to HAI titers for E) TX/91 HA and F) Ala/81 H3 were then determined using the above data and plotted, with means depicted by yellow lines. Data were compared using one-way repeated measures ANOVA. Means between exams were then compared using Tukey's multiple comparisons test to determine statistically significant differences, which are denoted by asterisks. n.s. = not significant.