title: Enhancing the potency of peptide-pulsed antigen presenting cells by vector-driven hyperexpression of a triad of costimulatory molecules.
abstract: Recombinant orthopox vectors (both replication-defective fowlpox [rF], and replication competent vaccinia [rV] have been developed that simultaneously express three T-cell costimulatory molecule transgenes. The constituents of this triad of costimulatory molecules (designated TRICOM) are B7-1, ICAM-1, and LFA-3. We have previously shown that infection of murine dendritic cells (DCs) with TRICOM vectors increases their level of expression of the triad of costimulatory molecules and enhances the efficacy of DCs to activate T cells. While DCs are arguably the most potent antigen presenting cell (APC), limitations clearly exist in their use due to the level of effort and cost for their generation. The studies reported here demonstrate that a generic APC population, murine splenocytes, can be made markedly more efficient as APCs by infection with either rF-TRICOM or rV-TRICOM vectors. Infection of splenocytes with either TRICOM vector led to significant improvement of APC capabilities in terms of: (a) enhancement of mixed lymphocyte reactions; (b) a reduction in the amount of signal 1 to activate naive T cells; and (c) a reduction in the amount of APCs required to activate T cells using a constant amount of signal 1. TRICOM-enhanced T-cell activation was shown to correspond to increases in type-1 cytokines and a reduced level of apoptosis, compared with T cells activated with uninfected or control vector-infected splenocytes. In vitro and in vivo experiments compared DCs with TRICOM-infected splenocytes. Infection of splenocytes with TRICOM vectors markedly enhanced their ability to activate T cells to levels approaching that of DCs. These studies thus demonstrate for the first time that an abundant and accessible population of APCs obtainable without lengthy culture or the use of costly exogenous cytokines (in contrast to that of DCs) can be made more potent as APCs with the use of vectors that express a triad of costimulatory molecules.
authors.affiliation: Laboratory of Tumor Immunology and Biology, National Cancer Institute, National Institutes of Health, Building 10, Room 8B07, 10 Center Drive, Bethesda, MD 20892-1750, USA.
authors.forename: J W
authors.initials: JW
authors.lastname: Hodge
authors.forename: D W
authors.initials: DW
authors.lastname: Grosenbach
authors.forename: A N
authors.initials: AN
authors.lastname: Rad
authors.forename: M
authors.initials: M
authors.lastname: Giuliano
authors.forename: H
authors.initials: H
authors.lastname: Sabzevari
authors.forename: J
authors.initials: J
authors.lastname: Schlom
mesh_terms: D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology*; D017209:Apoptosis; D018122:B7-1 Antigen / Q000008:administration & dosage / Q000235:genetics; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018968:CD58 Antigens / Q000008:administration & dosage / Q000235:genetics; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D003713:Dendritic Cells / Q000276:immunology; D005260:Female; D005587:Fowlpox virus / Q000235:genetics; D005822:Genetic Vectors; D016882:ISCOMs / Q000008:administration & dosage* / Q000235:genetics*; D007156:Immunologic Memory; D018799:Intercellular Adhesion Molecule-1 / Q000008:administration & dosage / Q000235:genetics; D007371:Interferon-gamma / Q000096:biosynthesis; D007376:Interleukin-2 / Q000096:biosynthesis; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D010047:Ovalbumin / Q000276:immunology; D013154:Spleen / Q000166:cytology / Q000276:immunology; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology; D014616:Vaccinia virus / Q000235:genetics
chemical_list: D018122:B7-1 Antigen; D018968:CD58 Antigens; D016882:ISCOMs; D007376:Interleukin-2; D018799:Intercellular Adhesion Molecule-1; D007371:Interferon-gamma; D010047:Ovalbumin