Autophagy recognizes intracellular Salmonella enterica serovar Typhimurium in damaged vacuoles

Abstract

Autophagy is responsible for the degradation of cytosolic components within eukaryotic cells. Interestingly, autophagy also appears to play a role in recognizing invading intracellular pathogens. Salmonella enterica serovar Typhimurium (S. Typhimurium) is an intracellular pathogen that normally resides and replicates within the Salmonella-containing vacuole (SCV). However, during in vitro infection a population of S. Typhimurium damage and escape from the SCV to enter the cytosol. We have observed that some intracellular S. Typhimurium are recognized by autophagy under in vitro infection conditions. Immunofluorescence studies revealed that autophagy recognizes the population of S. Typhimurium within damaged SCVs early after infection. The consequences of autophagic recognition of S. Typhimurium are still being elucidated, though a restrictive effect on intracellular bacterial replication has been demonstrated. Results of our in vitro infection studies are consistent with autophagy playing a role in cellular defense against S. Typhimurium that become exposed to the cytosol.