Staphylococcus aureus nasal carriage is associated with serum 25-hydroxyvitamin D levels, gender and smoking status. The Tromsø Staph and Skin Study

Vitamin D induces the expression of antimicrobial peptides with activity against Staphylococcus aureus. Thus, we studied the association between serum 25-hydroxyvitamin D (25(OH)D) and S. aureus nasal colonization and carriage. Nasal swabs, blood samples and clinical data from 2,115 women and 1,674 men, aged 30–87 years, were collected in the Tromsø Staph and Skin Study 2007–08, as part of the population-based sixth Tromsø Study. Multivariate logistic regression analyses were stratified by recognized risk factors for S. aureus carriage: sex, age and smoking. In non-smoking men, we observed a 6.6% and 6.7% decrease in the probability of S. aureus colonization and carriage, respectively, by each 5 nmol/l increase in serum 25(OH)D concentration (P < 0.001 and P = 0.001), and serum 25(OH)D > 59 nmol/l and ≥75 nmol/l as thresholds for ~30% and ~50% reduction in S. aureus colonization and carriage. In non-smoking men aged 44–60 years, the odds ratio for S. aureus colonization was 0.44 (95% confidence interval, 0.28−0.69) in the top tertile of serum 25(OH)D versus the bottom tertile. In women and smokers there were no such associations. Our study supports that serum vitamin D is a determinant of S. aureus colonization and carriage

Genetic Control of Resistance to Trypanosoma brucei brucei Infection in Mice

Trypanosoma brucei are extracellular protozoa transmitted to mammalian host by the tsetse fly. They developed several mechanisms that subvert host's immune defenses. Therefore analysis of genes affecting host's resistance to infection can reveal critical aspects of host-parasite interactions. Trypanosoma brucei brucei infects many animal species including livestock, with particularly severe effects in horses and dogs. Mouse strains differ greatly in susceptibility to T. b. brucei. However, genes controlling susceptibility to this parasite have not been mapped. We analyzed the genetic control of survival after T. b. brucei infection using CcS/Dem recombinant congenic (RC) strains, each of which contains a different random set of 12.5% genes of their donor parental strain STS/A on the BALB/c genetic background. The RC strain CcS-11 is even more susceptible to parasites than BALB/c or STS/A. In F2 hybrids between BALB/c and CcS-11 we detected and mapped four loci, Tbbr1-4 (Trypanosoma brucei brucei response 1–4), that control survival after T. b. brucei infection. Tbbr1 (chromosome 3) and Tbbr2 (chromosome 12) have independent effects, Tbbr3 (chromosome 7) and Tbbr4 (chromosome 19) were detected by their mutual inter-genic interaction. Tbbr2 was precision mapped to a segment of 2.15 Mb that contains 26 genes

Evaluation of Nod-Like Receptor (NLR) Effector Domain Interactions

Members of the Nod-like receptor (NLR) family recognize intracellular pathogens and recruit a variety of effector molecules, including pro-caspases and kinases, which in turn are implicated in cytokine processing and NF-κB activation

Interactions protéine - lipide : dans le cadre de l'induction de mécanismes de défense des plantes

Rapport bibliographique *INRA Dijon, Documentation, 17 rue Sully, BP 86510, 21065 Dijon cedex Diffusion du document : INRA Dijon, Documentation, 17 rue Sully, BP 86510, 21065 Dijon cedex Diplôme : DE

Interactions protéine - lipide : dans le cadre de l'induction de mécanismes de défense des plantes

Rapport bibliographique *INRA Dijon, Documentation, 17 rue Sully, BP 86510, 21065 Dijon cedex Diffusion du document : INRA Dijon, Documentation, 17 rue Sully, BP 86510, 21065 Dijon cedex Diplôme : DE

Characterizing CEACAM5 interaction with CD8α and CD1d in intestinal homeostasis.

Normal intestinal epithelial cells (IECs) could act as non-professional antigen-presenting cells, selectively activating CD8(+)-suppressor T cells. An epithelial cell surface glycoprotein, gp180, recognized by monoclonal antibodies B9 and L12 was determined to be critical in this process. Purification and sequence analysis of mAb B9 reactive material revealed amino-acid sequence homology with CEACAM5. We demonstrate that CEACAM5 has properties attributed to gp180, such as CD8α binding and activation of CD8-associated Lck. CEACAM5 is the only CEACAM member interacting with CD1d through the B3 domain. Its N domain (recognized by B9) is required for CD8α binding. Removal of the N-domain glycosylated residues reduces B9 recognition, CD8α binding affinity, and activation of LcK. Therefore, conformational changes in CEACAM5 glycosylation site are critical for its interaction with CD8α. CEACAM5-activated CD8(+) T cells acquire the ability to suppress the proliferation of CD4(+) T cells in vitro in the presence of interleukin (IL)-15 or IL-7. We provide new insights into the role of CEACAM5 and define its specific immunoregulatory properties among the CEACAMs expressed on IECs. We suggest that unique set of interactions between CEACAM5, CD1d, and CD8 render CD1d more class I-like molecule, facilitating antigen presentation and activation of CD8(+)-suppressor regulatory T cells

Assessment of the immunoglobulin E-mediated immune response to milk-specific proteins in allergic patients using microarrays.

International audienceBACKGROUND: Cow's milk allergy (CMA) is one of the most widespread human allergies, especially in young children. Although CMA is intensively studied, little is known about the recognition patterns of milk allergens in allergic patients, and the determination these patterns is a prerequisite for the development of efficient diagnostic and prognostic tools. Several factors present difficulties for such a determination, because (i) milk contains a large number of potential allergens; (ii) the majority of these allergens consist of complex suspensions rather than solutions; (iii) the major allergens, such as caseins, cannot be highly purified in large amounts; and (iv) most of the time, very small amount of young patients' sera are readily available. METHODS: To overcome these difficulties, we developed a sensitive microarray assay that, in combination with near-infrared fluorescence detection, was used to study the immune response to milk and purified native milk proteins. RESULTS: This new assay allowed us to assess the binding ability of IgE to milk allergens from a large number of young patients using reduced amounts of clinical material. The data show that bovine lactoferrin can be classed as a strong milk allergen. We confirmed that bovine caseins are the main allergens in milk and that alpha(S1)-casein is more allergenic than alpha(S2)-, beta- and kappa-caseins, which were recognized with almost a similar frequency by the sera of patients. CONCLUSION: Microarray methods, in combination with near-infrared fluorescence detection, can be useful for the in vitro diagnosis of food allergies

Mouse and human Notch-1 regulate mucosal immune responses.

The Notch-1 signaling pathway is responsible for homeostatic tight junction expression in vitro, and promotes barrier function in vivo in the RAG1-adoptive transfer model of colitis. In this study, we sought to determine the role of colonic Notch-1 in the lymphoepithelial crosstalk in health and disease. We utilized in vivo and in vitro knockdown to target the expression of Notch-1. We identified that epithelial Notch-1 is required for appropriate activation of intestinal epithelial cells at steady state and upon inflammatory stimulus. Notch-1 expression modulates mucosal chemokine and cytokine secretion, and FoxP3 and effector T-cell responses. We showed that epithelial Notch-1 controls the immune function of the epithelium through crosstalk with the nuclear factor-jB (NF-jB)/mitogen-activated protein kinase (MAPK) pathways that, in turn, elicits T-cell responses. Overall, epithelial Notch-1 bridges innate and adaptive immunity in the gut. Our findings highlight an indispensable role for Notch-1-mediated signaling in the intricate epithelial-immune crosstalk, and validate that epithelial Notch-1 is necessary and sufficient to support protective epithelial proinflammatory responses