title: Adhesion molecules involved in the interactions between early T cells and mesenchymal bone marrow stromal cells.
abstract: We previously reported that among the various thymic lymphocyte subpopulations, the immature T cells preferentially adhere to mesenchymal bone marrow stroma. In the present study we examined the interactions between phenotypically defined populations of early T cells and stromal cell lines. The immature T cells segregated into two subpopulations according to their adhesive capacity. Whereas the majority of the adherent CD4-CD8- T cells were devoid of CD3/TCRalphabeta, most of the nonadherent CD4-CD8- T cells expressed this receptor complex. The adhesion of T cells to bone marrow stroma almost entirely was accounted for by CD49d and CD90, whereas that of adherent CD4-CD8- cells also was dependent on CD44, CD62L, and CD117 receptor. Blocking antibody combinations failed to reduce the adherence of these early T cells to less than 50% that of the control. On the other hand, the adhesion of unselected thymocytes to the stroma was reduced by 80%, using the same blocking antibodies. Therefore, the participation of additional molecules in the adhesion of early T cells to mesenchymal stroma is implicated. Comparison between the interaction of T cells with bone marrow mesenchymal or with thymus-derived epithelial stroma indicated that T cells utilize a selected set of adhesion molecules under each situation. Although CD49d and CD90 participated in both cases, CD11a, CD18, and CD2 receptors played a dominant role in the adhesion of T cells to thymic epithelium only. This study may point to a role of mesenchymal stroma in the regulation of early T-cell lymphopoiesis in the bone marrow.
authors.affiliation: Department of Life Sciences, Bar-Ilan University, Ramat Gan, Israel.
authors.forename: M
authors.initials: M
authors.lastname: Barda-Saad
authors.forename: L A
authors.initials: LA
authors.lastname: Rozenszajn
authors.forename: H
authors.initials: H
authors.lastname: Ashush
authors.forename: Y
authors.initials: Y
authors.lastname: Shav-Tal
authors.forename: A
authors.initials: A
authors.lastname: Ben Nun
authors.forename: D
authors.initials: D
authors.lastname: Zipori
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D001483:Base Sequence; D001854:Bone Marrow Cells / Q000166:cytology*; D002448:Cell Adhesion / Q000502:physiology; D015815:Cell Adhesion Molecules / Q000502:physiology*; D002460:Cell Line; D018920:Coculture Techniques; D017931:DNA Primers; D016130:Immunophenotyping; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D018613:Microscopy, Confocal; D010641:Phenotype; D017154:Stromal Cells / Q000166:cytology*; D013601:T-Lymphocytes / Q000166:cytology* / Q000276:immunology; D013950:Thymus Gland / Q000166:cytology
chemical_list: D015703:Antigens, CD; D015815:Cell Adhesion Molecules; D017931:DNA Primers