<i>In vivo</i> CD4⁺ T cell response to OVA-decorated BCG.

<p>C57BL/6 mice were injected subcutaneously with BCG surface decorated with OVA, unmodified BCG wild-type, PBS (control), BCG genetically transformed to express OVA (BCG-p19-OVA) or transformed with control plasmid and surface decorated with Avi-OVA (BCG-p19-AviOVA). After a 20-day period, splenocytes were prepared from the spleens of euthanized animals and stained with PE-conjugated I-A^b-OVA_323-339 tetramers (A) or PE-conjugated I-A^b-Ag85B_280-294 tetramer (B) followed by AF647-CD4 Ab and 7-AAD. Samples were then analyzed by FACS. Results are expressed as two-parameter dot plots that show the average frequencies± SEM of tetramer positive events in the CD4⁺ population from two animals/group. Data shown are representative of three independent experiments. The data in graphs (C) are expressed as mean value± SEM of the absolute number (in a total of 500,000 events) of OVA Tetramer specific CD4⁺ cells in (left graph) or Ag85B Tetramer specific CD4⁺ T cells (right graph) from two animals/group and three independent experiments. *P<0.05; **P<0.01; ***P<0.001.