title: Postnatal development of bronchus-associated lymphoid tissue (BALT) in the rat, Rattus norvegicus.
abstract: The pattern of development of bronchus-associated lymphoid tissue (BALT) in specified-pathogen-free and conventional (non-barrier maintained) rats over the initial 4 weeks of life appeared to be similar. BALT first appeared around the 2nd week of life and increased in amount over the following 2 weeks. Overlying large nodules of BALT the bronchial epithelium becomes infiltrated by lymphocytes to form a lymphoepithelium. This transformation occurs earlier in conventional rats, possibly because of the differing antigen levels to which they are exposed.
mesh_terms: D000818:Animals; D001980:Bronchi / Q000033:anatomy & histology / Q000254:growth & development*; D005260:Female; D008221:Lymphoid Tissue / Q000033:anatomy & histology / Q000254:growth & development*; D008297:Male; D051381:Rats / Q000033:anatomy & histology / Q000254:growth & development*; D013047:Specific Pathogen-Free Organisms