Differential expression of adhesion molecules within the human thymus.
Development of a diverse, MHC-restricted yet self-tolerant T-cell repertoire occurs within the thymus, and requires contact between developing T cells and their stromal microenvironment. Such interactions are likely to depend on the combinatorial effect of specific adhesion molecules. As a preliminary step to determining their role in T-cell development, we have studied the distribution of LFA-1/ICAM-1, CD2/LFA-3, VLA-4/VCAM-1, and HECA 452-antigen/E-Selectin ligand pairs on frozen sections of human thymus. Using two color-immunohistochemistry, and a variety of cell-lineage markers that reveal the nature of the cells on which these adhesion molecules are located, we find a differential distribution of adhesion molecules, with some being shared by both endothelial and epithelial cells. We also identify the VCAM-1-positive subpopulation as cortical macrophages. The relevance of these findings to thymopoiesis is discussed.
Reza
J N
JN
Department of Immunology, Royal Postgraduate Medical School, London, U.K.
Ritter
M A
MA
D015815:Cell Adhesion Molecules / Q000096:biosynthesis*; D002454:Cell Differentiation; D002675:Child, Preschool; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D007231:Infant, Newborn; D008264:Macrophages / Q000378:metabolism; D017154:Stromal Cells / Q000378:metabolism; D013950:Thymus Gland / Q000378:metabolism*
D015815:Cell Adhesion Molecules