title: Evidence for direct and indirect pathways in the generation of the alloimmune response against pancreatic islets.
abstract: The role of the direct and indirect pathways of alloantigen presentation in the generation of the alloimmune response was dissected using the murine mixed lymphocyte-islet coculture system (MLIC). Stimulator DBA/2J (H-2d) pancreatic islet populations consisted of whole islets (MHC class I+, II+) or FACS-purified beta cells (MHC class I+, II-). Responding C57Bl/6 (H-2b) splenocyte populations were either: (1) untreated; (2) depleted of helper T cells with anti-L3T4 monoclonal antibody plus complement; (3) depleted of cytotoxic T lymphocytes with anti-Lyt2 mAb plus complement; or (4) depleted of antigen-presenting cells by passage through a Sephadex G-10 column. Whole islets were capable of stimulating a significant C57Bl/6 anti-DBA cytotoxic T cell response if the responding population was untreated or treated with complement alone. Depletion of responding splenocytes with either anti-Lyt2 or anti-L3T4 mAb plus complement abrogated the generation of allospecific CTL. If the responding splenocyte population was depleted of APCs, the allo-CTL response against whole islets was decreased, but still significant. If, however, the stimulator population consisted of FACS-purified DBA 2J beta cells, APC-depleted C57Bl 6 splenocytes were incapable of generating any CTL response. Adding responder type (C57Bl/6) APCs back to the microwells restored the capacity for both whole islets and purified beta cells to stimulate a strong allo-CTL response. These data demonstrate that both indirect and direct pathways of alloantigen presentation function in the MLIC.
authors.affiliation: Department of Surgery, University of Minnesota Hospitals, Minneapolis 55455.
authors.forename: P G
authors.initials: PG
authors.lastname: Stock
authors.forename: N L
authors.initials: NL
authors.lastname: Ascher
authors.forename: S
authors.initials: S
authors.lastname: Chen
authors.forename: J
authors.initials: J
authors.lastname: Field
authors.forename: F H
authors.initials: FH
authors.lastname: Bach
authors.forename: D E
authors.initials: DE
authors.lastname: Sutherland
mesh_terms: D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D007515:Islets of Langerhans / Q000276:immunology*; D007518:Isoantibodies / Q000276:immunology*; D007519:Isoantigens / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D007959:Lymphocyte Culture Test, Mixed; D016131:Lymphocyte Subsets / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D010641:Phenotype; D013154:Spleen / Q000166:cytology / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology
chemical_list: D000949:Histocompatibility Antigens Class II; D007518:Isoantibodies; D007519:Isoantigens