Figure 4

Induction of CD4⁺ Th1 cell response to HBsAg peptides. Unstimulated and HBsAg peptides-stimulated PBMC were stained with fluorochrome-conjugated CD3, CD4, CD8, IFN-γ, TNF-α, IL-2 specific antibodies. The percentage of CD3⁺CD4⁺ T lymphocytes expressing at least one cytokine was determined by flow cytometry. Background cytokine expression from unstimulated cells was subtracted from HBsAg peptides-stimulated cells and the induction of Th1 response at D29 (open circle), D36 (gray circle), D57 (dark gray circle) or D85 (closed circle) compared to D1 was calculated for each subject displaying a statistically significant increase (p < 0.05, see Figure 3) using the formula:

\frac{(\%{\text{ of cytokines}}^{+}\text{ cells at D}29\text{ or D}36\text{ or D}57\text{ or D}85)\times 100}{\%{\text{ of cytokines}}^{+}\text{ cells at D}1}-100