title: Coupling presentation of MHC class I peptides to constitutive activation of antigen-presenting cells through the product of a single gene.
abstract: Priming of naive CD8 T cells by dendritic cells (DCs) entails both effective antigen presentation on MHC class I products and co-stimulatory signaling. Their optimal coupling is a major goal in the development of CTL-inducing vaccines. We recently reported that a membranal derivative of the invariant MHC-I light chain, β(2)-microglobulin (β(2)m), markedly stabilizes MHC-I molecules and can serve as a universal platform for exceptional presentation of genetically linked peptides. To test whether it is possible to equip the resulting MHC-I complexes with an inherent ability to activate antigen-presenting cells, we engrafted the intracellular Toll/IL-1 receptor domain of mouse Toll-like receptor (TLR) 4 or TLR2 onto the peptide-β(2)m scaffold. We evaluated the level of peptide presentation and status of cell activation conferred by such constructs in stably transfected mouse RAW264.7 macrophages and mRNA-transfected mouse DC2.4 DCs. We show that the encoded peptide-β(2)m-TLR polypeptides are expressed at the cell surface, pair with endogenous heavy chains, stabilize MHC-I products, prompt efficient peptide-specific T-cell recognition and confer a constitutively activated phenotype on the transfected cells, as judged by the up-regulation of pro-inflammatory genes and surface co-stimulatory molecules. Our results provide evidence that the product of a single recombinant gene can couple MHC peptide presentation to TLR-mediated signaling and offer a safe, economical and highly versatile modality for a novel category of genetic CTL-inducing vaccines.
authors.affiliation: Laboratory of Immunology, MIGAL Research Institute, Kiryat Shmona, Israel.
authors.forename: Gal
authors.initials: G
authors.lastname: Cafri
authors.forename: Eytan
authors.initials: E
authors.lastname: Amram
authors.forename: Gal
authors.initials: G
authors.lastname: Rinott
authors.forename: Gabriela
authors.initials: G
authors.lastname: Koifman
authors.forename: Sigal
authors.initials: S
authors.lastname: Fishman
authors.forename: Yona
authors.initials: Y
authors.lastname: Keisari
authors.forename: Esther
authors.initials: E
authors.lastname: Tzehoval
authors.forename: Alon
authors.initials: A
authors.lastname: Margalit
authors.forename: Lea
authors.initials: L
authors.lastname: Eisenbach
authors.forename: Gideon
authors.initials: G
authors.lastname: Gross
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000276:immunology*; D000938:Antigen-Presenting Cells / Q000276:immunology*; D005822:Genetic Vectors / Q000235:genetics; D006183:H-2 Antigens / Q000276:immunology*; D008264:Macrophages / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D010455:Peptides / Q000235:genetics / Q000276:immunology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051193:Toll-Like Receptors / Q000235:genetics / Q000276:immunology; D014162:Transfection; D001613:beta 2-Microglobulin / Q000235:genetics / Q000276:immunology
chemical_list: D006183:H-2 Antigens; D010455:Peptides; D012333:RNA, Messenger; D051193:Toll-Like Receptors; D001613:beta 2-Microglobulin