FIG. 2.

Late endosomal-lysosomal compartments of B lymphocytes lack Salmonella enterica serovar Typhimurium degradation and favor bacterial survival. After 1, 3, and 18 h postinfection with radiolabeled bacteria, intracellular SCV of activated macrophages and B lymphocytes were obtained by Percoll gradient separation. Salmonella-derived radioactivity within vacuoles was detected by beta scintillation analysis of the fractions. The distribution of late endosome-lysosome across the gradient was detected by β-hexosaminidase enzymatic activity. On the left y axis, we present the percentage of total radioactivity, the percentage of total β-hexosaminidase activity is displayed on the right y axis, and the x axis corresponds to the number of gradient density fractions. One representative experiment out of three is presented for β-hexosaminidase quantification and radioactive detection of SCV.