1. T-cell stimulation by SPI-2-mediated delivery of a model antigen from S. Typhimurium ΔsseG ΔsopD2 ΔsrfH.
T-cell stimulation by SPI-2-mediated delivery of a model antigen from S. Typhimurium ΔsseG ΔsopD2 ΔsrfH. Bone marrow-derived dendritic cells (BM-DC) were infected with indicated S. Typhimurium strains harboring the plasmid pWSK29 PsseAsseJ::OVA::HA (p3631). Cells infected with wild-type S. Typhimurium, in the absence of the plasmid, were used as a negative control. Stimulation with the SIINFEKL peptide was used as a positive control. Infected cells were cocultured for 22 h with B3Z T-cell hybridoma reporter cells (ratio of BM-DC to T cells of 1:4) followed by a 6-h incubation in the presence of the β-galactosidase substrate chlorophenyl red β-galactopyranoside. β-Galactosidase activity was measured colormetrically by the amount of substrate converted at 595 nm. Results were normalized to values obtained with the negative control and are expressed as means ± SEM of the results of four independent experiments, each performed in triplicate. P values were obtained by Student’s t test relative to the wild-type negative-control results (*, P < 0.05; **, P < 0.01).
Rita Figueira et al. mBio 2013; doi: /mBio