The M. tuberculosis Phosphate-Binding Lipoproteins PstS1 and PstS3 Induce Th1 and Th17 Responses That Are Not Associated with Protection against M. tuberculosis Infection
Figure 4
Cytokine production in response to PstS1 or PstS3 proteins in spleen cells of immunized mice. Pooled spleen cells (3 mice/group) of mice vaccinated with PstS3 antigen (panels (a) and (b)) or with PstS1 antigen (panels (c) and (d)) were cultured at cells/well and re-stimulated ex vivo with PstS1 or PstS3 proteins (5 μg/mL each) for 4 days before measuring IFN-γ ((a) and (c)) or IL-17 ((b) and (d)) in the supernatant of culture by specific ELISA kit. Data were combined from 3 independent experiments and are presented as mean. Error bars indicate SEM. §Statistical significant difference between PstS1- and PstS3-induced responses in each group of immunized mice ( or determined by a two-tailed Student’s t-test). In some experiments spleen cells of DNA x4-, DNA/protein-LTK63-, or protein/LTK63-immunized mice with both PstS3 (e) or PstS1 (f) antigens were depleted of CD4+ T cells by using magnetic beads as described in Materials and Methods. Undepleted cells and CD4+ T cell-depleted subset were re-stimulated with PstS1 or PstS3 protein (5 μg/mL) for 4 days before testing the IFN-γ by a specific ELISA kit ((e) and (f)). Error bars indicate SEM. The level of statistical significance for differences among undepleted cells and CD4+ T cell-depleted subset in each group was determined by Student’s t-test (; ).
