FIG 2.

HIV Env DNA vaccination to intramuscular and intradermal sites maintains durable immune responses at the memory time point. (A) Immunization schedule for tissue-specific DNA vaccination. C57BL/6 mice were immunized twice, 2 weeks apart (n = 4 to 5 per group), either intramuscularly or intradermally. Spleens and skin from the flank and TA were collected 75 days after the final vaccination to analyze antigen-specific immune responses. (B) The frequency of Env-specific IFN-γ (spot-forming units per million splenocytes) maintained at the memory time point was determined by an IFN-γ ELISpot assay in response to pooled Env peptides. (C) Env-specific CD4⁺ T cell responses by intracellular cytokine staining at the vaccination site.