Fig 2.

M. tuberculosis- and p24-specific cellular responses induced by pP24-Mtb immunization. Two weeks after the last immunization, splenocytes were harvested and stimulated with M. tuberculosis peptides or p24 protein in vitro. (A) Lymphocyte proliferation was measured and expressed as stimulation index (SI). (B) IFN-γ-secreting lymphocytes were quantified by ELISPOT assay. Images represent splenic ELISPOT responses in the immunized mice. (C) Frequency of IFN-γ-secreting cells in the spleens of mice measured by ELISPOT assay. (D and E) The percentages of CD4⁺ IFN-γ⁺ or CD8⁺ IFN-γ⁺ T cells in the spleens were analyzed by flow cytometry following M. tuberculosis peptide stimulation (D) or following p24 stimulation (E). (F) M. tuberculosis- and p24-specific CTL activity was expressed as the percent cytotoxicity. Data in the graph are from one representative experiment of three independent experiments performed. Error bars represent the means plus standard deviations (SD) (n = 6). Values that are statistically significantly different (P < 0.05) are indicated by a short horizontal line and an asterisk.