Characteristics of chicken intraembryonic cells that express B-L (Ia-like) antigen under the influence of cultured bursal epithelium.
In-vitro-cultured bursal epithelium (BE) and BE-conditioned medium (BECM) induce B-L antigen on chicken intraembryonic cells. Cells prepared from 9-day-old intraembryonic mesoderm were fractionated in accordance with cell size by linear albumin gradient sedimentation at 1 g. Two cell types could be distinguished on which expression of the B-L antigen was altered after a 6-h incubation with the bursal epithelial component. One fraction contained small mononuclear cells with low sedimentation velocity (less than or equal to 3 mm/h) and low spontaneous proliferation activity. These cells responded strongly to BECM and showed a slight but not significant response to BE (index after incubation with BECM 3.8, with BE 1.7, as compared with RPMI medium control). The other fraction was composed of large mononuclear cells with sedimentation velocity greater than 9 mm/h and with high spontaneous proliferation. These cells showed a response of equal magnitude to both BE and BECM (index after incubation with BE 2.0, with BECM 2.3). These results suggest that the bursa of Fabricius has influence on two different cell types: a large, probably primitive undifferentiated cell, responding equally to bursal cellular contacts and BE culture supernatant, and a small mononuclear cell type, probably more mature, responding more clearly to the bursal humoral factor.
D000818:Animals; D002060:Bursa of Fabricius / Q000166:cytology / Q000276:immunology; D002469:Cell Separation; D002642:Chick Embryo / Q000276:immunology*; D002645:Chickens; D003470:Culture Media; D004848:Epithelium / Q000276:immunology; D004912:Erythrocytes / Q000166:cytology / Q000378:metabolism; D004920:Erythropoiesis; D000949:Histocompatibility Antigens Class II / Q000032:analysis*; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000145:classification* / Q000276:immunology
D003470:Culture Media; D000949:Histocompatibility Antigens Class II