title: Role of environmental antigens in B cell proliferation in the bursa of Fabricius at neonatal stage.
abstract: Effect of environment antigens on S phase entry rate of bursa cells was studied by utilizing in vivo incorporation of bromodeoxyuridine (BrdUrd). S phase entry rate of bursa cells in chick embryo was determined to be 6.4%/h, this rate increased to 10.0%/h at neonatal stage and decreased to 6.4%/h 6 weeks after hatching. Evidence is presented that isolation of the bursa from the gut before hatching suppressed S phase entry rate of bursa cells after hatching, whereas S phase entry rates of thymocytes were not affected. On tissue sections, a decrease of BrdUrd+ cells was observed in medullary areas of the isolated bursa. It is proposed that in situ stimulation of bursa cells by environmental antigens to the bursa accelerates S phase entry rates, and that medullary areas are the major sites for antigen-driven B cell proliferation after hatching.
authors.affiliation: Department of Anatomy, Kumamoto University Medical School, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Ekino
mesh_terms: D000367:Age Factors; D000818:Animals; D000941:Antigens / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D002060:Bursa of Fabricius / Q000033:anatomy & histology / Q000166:cytology / Q000276:immunology*; D002642:Chick Embryo; D002645:Chickens / Q000276:immunology*; D004777:Environment; D008213:Lymphocyte Activation; D009929:Organ Size; D012044:Regression Analysis; D016196:S Phase; D013950:Thymus Gland / Q000166:cytology
chemical_list: D000941:Antigens