title: Development of the palatine tonsil in conventional and germ-free piglets.
abstract: Palatine tonsils, like the Peyer's patches, are considered to be major inductive sites for the mucosa-associated lymphoid tissue (MALT), providing sampling and effector functions for the upper respiratory tract. Consistent with this, they have the architecture required of a classic inductive site (B-cell follicles, immunoglobulin class switching and the presence of naïve and memory T-cells). Here we show that much of this architecture develops after birth in the neonatal piglet, the numbers of T-cells, B-cells and accessory cells increasing with age. Conventional piglets also had higher levels of activated and memory T-cell subsets than germ-free piglets, consistent with development occurring as a result of microbial stimulus. The results suggest that the microbial environment influences the development of the tonsil immunological architecture. Given the role of the tonsil in induction of mucosal responses, this raises questions as to the effectiveness of the tonsil in dealing with colonising organisms in the neonate.
authors.affiliation: Division of Veterinary Pathology, Infection and Immunity, School of Clinical Veterinary Science, University of Bristol, Langford House, Bristol BS40 5DU, UK.
authors.forename: Stephen
authors.initials: S
authors.lastname: Wilson
authors.forename: Pam
authors.initials: P
authors.lastname: Norton
authors.forename: Karin
authors.initials: K
authors.lastname: Haverson
authors.forename: James
authors.initials: J
authors.lastname: Leigh
authors.forename: Michael
authors.initials: M
authors.lastname: Bailey
mesh_terms: D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology; D005856:Germ-Free Life; D014066:Palatine Tonsil / Q000033:anatomy & histology / Q000254:growth & development* / Q000276:immunology*; D034421:Sus scrofa / Q000033:anatomy & histology / Q000254:growth & development* / Q000276:immunology*; D013552:Swine; D013556:Swine, Miniature / Q000033:anatomy & histology / Q000254:growth & development* / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology