title: Migratory monocytes and granulocytes are major lymphatic carriers of Salmonella from tissue to draining lymph node.
abstract: Dendritic cells (DC) are recognized as sentinels, which capture antigens in tissue and migrate to the lymph node, where they initiate immune responses. However, when a vaccine strain of green fluorescent protein-expressing Salmonella abortusovis (SAO) was inoculated into sheep oral mucosa, it induced accumulation of myeloid non-DC in the subcapsular sinus and paracortex of the draining lymph node, and SAO was mainly found associated with these cells (granulocytes and macrophages) but rarely with DC. To analyze how bacteria reached lymph nodes, we used cervical pseudo-afferent lymph duct catheterization. We showed that Salmonella administered in the oral mucosa were traveling free in lymph or associated with cells, largely with lymph monocytes and granulocytes but less with DC. SAO also induced a strong influx of these phagocytic cells in afferent lymph. Migrating DC presented a semi-mature phenotype, and SAO administration did not alter their expression of major histocompatibility complex type 2 and coactivation molecules. Compared with blood counterparts, lymph monocytes expressed lower levels of CD40, and granulocytes expressed higher levels of CD80. The data suggest that immunity to bacteria may result from the complex interplay between a mixture of phagocytic cell types, which transport antigens and are massively recruited via lymph to decisional lymph nodes.
authors.affiliation: Domaine de Vilvert, 78352 Jouy-en-Josas Cedex, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Bonneau
authors.forename: Mathieu
authors.initials: M
authors.lastname: Epardaud
authors.forename: Fabrice
authors.initials: F
authors.lastname: Payot
authors.forename: Violeta
authors.initials: V
authors.lastname: Niborski
authors.forename: Maria-Isabel
authors.initials: MI
authors.lastname: Thoulouze
authors.forename: Florence
authors.initials: F
authors.lastname: Bernex
authors.forename: Bernard
authors.initials: B
authors.lastname: Charley
authors.forename: Sabine
authors.initials: S
authors.lastname: Riffault
authors.forename: Laurence A
authors.initials: LA
authors.lastname: Guilloteau
authors.forename: Isabelle
authors.initials: I
authors.lastname: Schwartz-Cornil
mesh_terms: D000818:Animals; D002634:Chemotaxis, Leukocyte / Q000276:immunology*; D003713:Dendritic Cells; D005260:Female; D006098:Granulocytes / Q000276:immunology* / Q000382:microbiology; D049452:Green Fluorescent Proteins / Q000276:immunology; D008198:Lymph Nodes / Q000276:immunology*; D009000:Monocytes / Q000276:immunology* / Q000382:microbiology; D009061:Mouth Mucosa / Q000276:immunology; D010641:Phenotype; D012475:Salmonella / Q000276:immunology*; D012481:Salmonella Infections, Animal / Q000276:immunology* / Q000382:microbiology; D012756:Sheep
chemical_list: D049452:Green Fluorescent Proteins