title: CD2 is involved in maintenance and reversal of human alloantigen-specific clonal anergy.
abstract: Induction and maintenance of a state of T cell unresponsiveness to specific alloantigen would have significant implications for human organ transplantation. Using human histocompatibility leukocyte antigen DR7-specific helper T cell clones, we demonstrate that blockade of the B7 family of costimulatory molecules is sufficient to induce alloantigen-specific T cell clonal anergy. Anergized cells do not respond to alloantigen and a variety of costimulatory molecules, including B7-1, B7-2, intercellular adhesion molecule-1 (ICAM-1), and lymphocyte function-associated molecule (LFA)-3. However, after culture in exogenous interleukin (IL)-2 for at least 7 d, anergized cells can respond to alloantigen in the presence of LFA-3. LFA-3 costimulation subsequently restores responsiveness to alloantigen in the presence of previously insufficient costimulatory signals. Expression of CD2R epitope is downregulated on anergic cells and is restored after 7 d of IL-2 culture. The loss of the CD2R is temporally associated with the inability of anergized cells to respond to LFA-3. These results suggest that in addition to blockade of B7 family members, inhibition of CD2 and, potentially, other costimulatory pathways that might reverse anergy will be necessary to maintain prolonged alloantigen-specific tolerance.
authors.affiliation: Dana-Farber Cancer Institute, Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115.
authors.forename: V A
authors.initials: VA
authors.lastname: Boussiotis
authors.forename: G J
authors.initials: GJ
authors.lastname: Freeman
authors.forename: J D
authors.initials: JD
authors.lastname: Griffin
authors.forename: G S
authors.initials: GS
authors.lastname: Gray
authors.forename: J G
authors.initials: JG
authors.lastname: Gribben
authors.forename: L M
authors.initials: LM
authors.lastname: Nadler
mesh_terms: D000069594:Abatacept; D015703:Antigens, CD / Q000502:physiology; D000943:Antigens, Differentiation / Q000502:physiology; D018122:B7-1 Antigen / Q000502:physiology; D018801:CD2 Antigens / Q000502:physiology*; D018968:CD58 Antigens; D060908:CTLA-4 Antigen; D017635:Clonal Anergy; D002999:Clone Cells; D000939:Epitopes; D015809:HLA-DR7 Antigen / Q000502:physiology; D006801:Humans; D018796:Immunoconjugates; D007376:Interleukin-2 / Q000494:pharmacology; D007519:Isoantigens / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000502:physiology
chemical_list: D015703:Antigens, CD; D000943:Antigens, Differentiation; D018122:B7-1 Antigen; D018801:CD2 Antigens; D018968:CD58 Antigens; D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human; D000939:Epitopes; D015809:HLA-DR7 Antigen; D018796:Immunoconjugates; D007376:Interleukin-2; D007519:Isoantigens; D008562:Membrane Glycoproteins; D000069594:Abatacept