Different Bacterial Pathogens, Different Strategies, Yet the Aim Is the Same: Evasion of Intestinal Dendritic Cell Recognition

Abstract

Given the central role of intestinal dendritic cells (DCs) in the regulation of gut immune responses, it is not surprising that several bacterial pathogens have evolved strategies to prevent or bypass recognition by DCs. In this article, we will review recent findings on the interaction between intestinal DCs and prototypical bacterial pathogens, such as Salmonella, Yersinia, or Helicobacter. We will discuss the different approaches with which these pathogens seek to evade DC recognition and subsequent T cell activation. These diverse strategies span to include mounting irrelevant immune responses, inhibition of Ag presentation by DCs, and stretch as far as to manipulate the Th1/Th2 balance of CD4+ T cells in the bacteria’s favor.

Absence of Platelet Endothelial Cell Adhesion Molecule 1, PECAM-1/CD31,In VivoIncreases Resistance to Salmonella enterica Serovar Typhimurium in Mice

“…Instead, the Salmonella bacteria interfere with the induction of adaptive immune responses and with the trafficking of dendritic cells to draining lymph nodes and the bloodstream. Residing sheltered from immune attack inside dendritic cells, S. Typhimurium exploits the migrating properties of dendritic cells to reach into deeper tissues and organs (35). Interestingly, our data showed reduced dissemination of Salmonella from the gastrointestinal tract into systemic organs in the absence of PECAM-1.…”

“…Various biological roles for PECAM-1 in thrombosis, inflammation, and the immune system have been identified (35). The role of PECAM-1 in the inflammatory process seems to depend on the stimulus and tissues involved and the genetic background when murine studies are concerned (reviewed in references 35, 36 and 37).…”

Wnt5a Signaling Promotes Host Defense against Leishmania donovani Infection

“…3), perhaps as a result of notable differences in their respective sizes and morphologies. In fact, interactions of the host cytoskeleton with different microbes vary significantly based on the characteristics of the microbes involved (45). Although Wnt5a does not have any direct effect on the L. donovani parasite (Supplemental Fig.…”

Recruitment of Dendritic Cells Is Responsible for Intestinal Epithelial Damage in the Pathogenesis of Necrotizing Enterocolitis by Cronobacter sakazakii

“…Nonetheless, several pathogens have developed strategies to suppress DC maturation so that they can thrive in hostile conditions (28). The stimulation of TLRs in DCs by pathogen-associated microbial patterns leads to the activation of various inflammatory signaling pathways and antimicrobial mechanisms (29).…”