Thymus: primary site of lymphopoiesis.
The thymus of the leopard frog is the primary, if not the sole, source of progenitor lymphocytic cells that normally colonize the spleen. Following embryonal parabiosis, a high level of cell chimerism exists in the thymus glands of each member of the parabiotic pair. Evidently, there can be an appreciable amount of cross-circulation of thymic cells between thymus glands.
D000818:Animals; D002454:Cell Differentiation; D006410:Hematopoiesis; D008214:Lymphocytes / Q000166:cytology*; D008297:Male; D010227:Parabiosis; D011894:Rana pipiens / Q000276:immunology; D013154:Spleen / Q000166:cytology / Q000196:embryology*; D013934:Thymectomy; D013950:Thymus Gland / Q000166:cytology / Q000196:embryology*