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Figure S1. Priming of CD4 T cells in CD40KO mice cannot be bypassed by LPS signals alone. (A) CD40KO mice were primed with WT or CD40KO H19-Env peptide-pulsed, LPS-matured DCs delivered s.c. After 4 wk, the mice were boosted with peptide in CFA s.c., and the frequency of tetramer⁺ CD4 T cells in the draining lymph nodes was assessed by FACS. **, P = 0.003. (B) Wild-type and CD40KO mice were primed with H19-Env peptide together with or without LPS (both in IFA). On day 9, the primary expansion of tetramer⁺ CD4 T cells in draining lymph nodes was assessed by FACS. *, P = 0.05. Background staining levels were set by H19-Env tetramer staining on cells from mice immunized with OVA peptide-pulsed DCs (A) or OVA peptide plus LPS in IFA (B). Staining of naive mice is also shown. Each point represents one mouse, and the line shows the mean of each group. This experiment was performed twice with similar results.