title: Dynamics of immune cell infiltration in the caecal lamina propria of chickens after neonatal infection with a Salmonella enteritidis strain.
abstract: Dynamics of leucocyte infiltration and bacterial invasion in the caecal wall were studied after oral infection of 2-day-old chicks with Salmonella enterica ser. Enteritidis. Bacteria invaded the lamina propria of the caecal wall from 12h post-challenge onwards. Bacteriological examination of internal organs (liver, spleen) showed a peak in Salmonella bacteria at 3days post-infection, after which the number of bacteria decreased. Immunohistochemistry revealed macrophages and T-lymphocytes invading the caecal propria mucosae from 24h after challenge onwards, while B-lymphocytes came somewhat later, subsequently organising into follicular aggregates. An early increase in granulocytes was partly masked by the response to natural flora. While the B-lymphocyte and granulocyte populations were maintained, T-lymphocyte and macrophage populations were already reducing by 10days post-challenge. The infiltration of macrophages and T-lymphocytes in the caecal wall, followed by B-lymphocytes, is the result of an inflammatory response, caused by invading bacteria at this site. The structural maturation of the mucosa-associated lymphoid tissues is antigen driven, since B-cells organise in a follicular pattern.
authors.affiliation: Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820, Merelbeke, Belgium. filip.vanimmerseel@rug.ac.be
authors.forename: Filip
authors.initials: F
authors.lastname: Van Immerseel
authors.forename: Jeroen
authors.initials: J
authors.lastname: De Buck
authors.forename: Isabel
authors.initials: I
authors.lastname: De Smet
authors.forename: Jan
authors.initials: J
authors.lastname: Mast
authors.forename: Freddy
authors.initials: F
authors.lastname: Haesebrouck
authors.forename: Richard
authors.initials: R
authors.lastname: Ducatelle
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001402:B-Lymphocytes / Q000276:immunology / Q000473:pathology; D002432:Cecum / Q000276:immunology* / Q000473:pathology; D002645:Chickens; D006098:Granulocytes / Q000276:immunology / Q000473:pathology; D007070:Immunoglobulin A / Q000378:metabolism; D007962:Leukocytes / Q000276:immunology / Q000473:pathology; D008099:Liver / Q000382:microbiology; D008264:Macrophages / Q000276:immunology / Q000473:pathology; D011201:Poultry Diseases / Q000276:immunology* / Q000382:microbiology / Q000473:pathology; D012481:Salmonella Infections, Animal / Q000276:immunology* / Q000382:microbiology / Q000473:pathology; D012477:Salmonella enteritidis; D013154:Spleen / Q000382:microbiology; D013601:T-Lymphocytes / Q000276:immunology / Q000473:pathology
chemical_list: D007070:Immunoglobulin A