CD4+ T cell immunity to Salmonella is transient in the circulation.

While Salmonella enterica is seen as an archetypal facultative intracellular bacterial pathogen where protection is mediated by CD4+ T cells, identifying circulating protective cells has proved very difficult, inhibiting steps to identify key antigen specificities. Exploiting a mouse model of vaccination, we show that the spleens of C57BL/6 mice vaccinated with live-attenuated Salmonella serovar Typhimurium (S. Typhimurium) strains carried a pool of IFN-γ+ CD4+ T cells that could adoptively transfer protection, but only transiently.

CCL17-expressing dendritic cells in the intestine are preferentially infected by Salmonella but CCL17 plays a redundant role in systemic dissemination.

Introduction: Salmonella spp. are a recognized and global cause of serious health issues from gastroenteritis to invasive disease. The mouse model of human typhoid fever, which uses Salmonella enterica serovar Typhimurium (STM) in susceptible mouse strains, has revealed that the bacteria gain access to extraintestinal tissues from the gastrointestinal tract to cause severe systemic disease.

CCL17 exerts a neuroimmune modulatory function and is expressed in hippocampal neurons.

Chemokines are important signaling molecules in the immune and nervous system. Using a fluorescence reporter mouse model, we demonstrate that the chemokine CCL17, a ligand of the chemokine receptor CCR4, is produced in the murine brain, particularly in a subset of hippocampal CA1 neurons. We found that basal expression of Ccl17 in hippocampal neurons was strongly enhanced by peripheral challenge with lipopolysaccharide (LPS).

RNA Aptamers Recognizing Murine CCL17 Inhibit T Cell Chemotaxis and Reduce Contact Hypersensitivity In Vivo.

The chemokine CCL17, mainly produced by dendritic cells (DCs) in the immune system, is involved in the pathogenesis of various inflammatory diseases. As a ligand of CCR4, CCL17 induces chemotaxis and facilitates T cell-DC interactions. We report the identification of two novel RNA aptamers, which were validated in vitro and in vivo for their capability to neutralize CCL17.