B7-2 (CD86) controls the priming of autoreactive CD4 T cell response against pancreatic islets.
The B7-1/2-CD28 system provides the critical signal for the generation of an efficient T cell response. We investigated the role played by B7-2 in influencing pathogenic autoimmunity from islet-reactive CD4 T cells in B7-2 knockout (KO) NOD mice which are protected from type 1 diabetes. B7-2 deficiency caused a profound diminishment in the generation of spontaneously activated CD4 T cells and islet-specific CD4 T cell expansion. B7-2 does not impact the effector phase of the autoimmune response as adoptive transfer of islet Ag-specific BDC2.5 splenocytes stimulated in vitro could easily induce disease in B7-2KO mice. CD4 T cells showed some hallmarks of hyporesponsiveness because TCR/CD28-mediated stimulation led to defective activation and failure to induce disease in NODscid recipients. Furthermore, CD4 T cells exhibited enhanced death in the absence of B7-2. Interestingly, we found that B7-2 is required to achieve normal levels of CD4+CD25+CD62L+ T regulatory cells because a significant reduction of these T regulatory cells was observed in the thymus but not in the peripheral compartments of B7-2KO mice. In addition, our adoptive transfer experiments did not reveal either pathogenic or regulatory potential associated with the B7-2KO splenocytes. Finally, we found that the lack of B7-2 did not induce a compensatory increase in the B7-1 signal on APC in the PLN compartment. Taken together these results clearly indicate that B7-2 plays a critical role in priming islet-reactive CD4 T cells, suggesting a simplified, two-cell model for the impact of this costimulatory molecule in autoimmunity against islets.
Yadav
Deepak
D
Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037, USA.
Judkowski
Valeria
V
Flodstrom-Tullberg
Malin
M
Sterling
Lori
L
Redmond
William L
WL
Sherman
Linda
L
Sarvetnick
Nora
N
D019264:Adoptive Transfer; D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology / Q000378:metabolism; D015703:Antigens, CD / Q000235:genetics / Q000502:physiology*; D001323:Autoantibodies / Q000096:biosynthesis; D001324:Autoantigens / Q000276:immunology*; D018122:B7-1 Antigen / Q000096:biosynthesis; D051940:B7-2 Antigen; D018106:CD28 Antigens / Q000276:immunology / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D002455:Cell Division / Q000235:genetics / Q000276:immunology; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics / Q000276:immunology / Q000517:prevention & control; D005260:Female; D007399:Interphase / Q000235:genetics / Q000276:immunology; D007515:Islets of Langerhans / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D008198:Lymph Nodes / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D008213:Lymphocyte Activation / Q000235:genetics / Q000276:immunology*; D018655:Lymphocyte Count; D008231:Lymphopenia / Q000235:genetics / Q000276:immunology; D008562:Membrane Glycoproteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D051379:Mice; D016688:Mice, Inbred NOD; D018345:Mice, Knockout; D016513:Mice, SCID; D011948:Receptors, Antigen, T-Cell / Q000276:immunology / Q000378:metabolism; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis; D013154:Spleen / Q000378:metabolism / Q000473:pathology / Q000637:transplantation; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism / Q000473:pathology
D015703:Antigens, CD; D001323:Autoantibodies; D001324:Autoantigens; D018122:B7-1 Antigen; D051940:B7-2 Antigen; D018106:CD28 Antigens; C497965:Cd86 protein, mouse; D008562:Membrane Glycoproteins; D011948:Receptors, Antigen, T-Cell; D015375:Receptors, Interleukin-2