Lymphocyte-differentiating hormone of bursa of fabricius

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Science  23 Jul 1976:
Vol. 193, Issue 4250, pp. 319-321
DOI: 10.1126/science.180600


Induction of early lymphocyte differentiation was studied in vitro in fractionated bone marrow cells of newly hatched chickens, with alloantiserums to identify newly differentiated B cells (Bu-1+) and T cells (Th-1+). Thymus extract induced selective T cell differentiation; the activity of the extract corresponds to that of thymopoietin. Bursal extract induced both B cell and T cell differentiation, but at lower concentrations B cell differentiation was always greater. This activity is ascribed to a lymphocyte-differentiating hormone of the bursa of Fabricius, for which the name bursopoietin is suggested.