Figure 2. Correlations of pH1N1 IFNγ ELISPOT results with pHN1 at baseline (A), post dose 1 (B) and post dose 2 (C). Data were derived from 67, 67 and 63 subjects in panels A, B and C, respectively. PBMC, frozen and thawed to preserve viability, were rested overnight. ELISPOT assays were performed only on PBMC with viability ≥ 70% both immediately after thawing and after resting. The assays used MabTech kits and live pH1N1 viral infection to promote stimulation of both CD4+ and CD8+ T cells. HAI titers were measured using pH1N1 antigens. Assays are described in detail in the methods section. The coefficients of correlation and p values shown on each graph were calculated using Spearman correlation test.