T cell tolerance and antigen presenting cell function in the thymus.
B7 expression appears much more extensive than previously recognized with anti-human B7 reagents on human leucocyte populations: it is extremely high on splenic and thymic DC, moderate on macrophages and activated B cells, and low on resting B cells. Additionally, B7 is entirely undetectable on any thymic epithelial cells belonging to a panel of transformed cell lines and T cells, but its expression on epithelial cells in situ is still under investigation. This expression pattern is consistent with the hierarchy of costimulatory signal activity among these cell types, with DC being the most effective, and epithelial cells (like other cells of non-hemopoietic origin) not at all. Future studies will investigate to which extent B7 is involved in clonal deletion, i.e., the selection process dependent on self-antigen presentation by DC and B cells.
Izon
D J
DJ
Division of Immunology, Netherlands Cancer Institute, Amsterdam.
Nieland
J D
JD
Jones
L A
LA
Kruisbeek
A M
AM
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000938:Antigen-Presenting Cells / Q000276:immunology*; D000951:Antigens, Neoplasm / Q000276:immunology; D015815:Cell Adhesion Molecules / Q000276:immunology; D006801:Humans; D007108:Immune Tolerance; D039641:Integrin beta Chains; D016023:Integrins / Q000276:immunology; D008213:Lymphocyte Activation; D051379:Mice; D008954:Models, Biological; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D015815:Cell Adhesion Molecules; D039641:Integrin beta Chains; D016023:Integrins; C091368:integrin beta7