title: CD40/APC-specific antibodies with three T-cell epitopes loaded in the constant domains induce CD4+ T-cell responses.
abstract: CD4+ T lymphocytes play a central role in the orchestration and maintenance of the adaptive immune response. Targeting of antigen to antigen presenting cells (APCs) increases peptide loading of major histocompatibility complex (MHC) class II molecules and CD4+ T-cell activation. APCs have been targeted by APC-specific recombinant antibodies (rAbs) with single T-cell epitopes integrated in the constant region of the heavy chain (C(H)). However, the strategy may be improved if several T-cell epitopes could be delivered simultaneously by one rAb. We here demonstrate that a single rAb can be loaded with multiple identical or different T-cell epitopes, integrated as loops between β-strands in C(H) domains. One epitope was inserted in C(H)1, while two were placed in C(H)2 of IgG. T-cell proliferation assays showed that all three peptides were excised from loops and presented on MHC class II to T-cells. Induction of T-cell activation by each epitope in the multi-peptide rAb was as good, or even better, than that elicited by corresponding single-peptide rAbs. Furthermore, following DNA vaccination of mice with plasmids that encode CD40-specific rAbs loaded with either one or three peptides, T-cell responses were induced. Thus, integration of multiple epitopes in C(H) region loops of APC-specific rAbs is feasible and may be utilized in design of multi-vaccines.
authors.affiliation: Centre for Immune Regulation, Department of Molecular Biosciences, University of Oslo, PO Box 1041, Blindern, NO-0316 Oslo, Norway.
authors.forename: Ingunn B
authors.initials: IB
authors.lastname: Rasmussen
authors.forename: Inger
authors.initials: I
authors.lastname: Oynebråten
authors.forename: Lene S
authors.initials: LS
authors.lastname: Høydahl
authors.forename: Morten
authors.initials: M
authors.lastname: Flobakk
authors.forename: Elin
authors.initials: E
authors.lastname: Lunde
authors.forename: Terje E
authors.initials: TE
authors.lastname: Michaelsen
authors.forename: Bjarne
authors.initials: B
authors.lastname: Bogen
authors.forename: Inger
authors.initials: I
authors.lastname: Sandlie
mesh_terms: D000818:Animals; D017951:Antigen Presentation; D000938:Antigen-Presenting Cells / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D019013:CD40 Antigens / Q000276:immunology*; D000939:Epitopes / Q000276:immunology*; D005803:Genes, Immunoglobulin; D005822:Genetic Vectors; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D006801:Humans; D007127:Immunoglobulin Constant Regions / Q000235:genetics / Q000276:immunology*; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008822:Mice, Transgenic; D008958:Models, Molecular; D010957:Plasmids; D011487:Protein Conformation; D015202:Protein Engineering; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology; D037182:T-Cell Antigen Receptor Specificity; D014611:Vaccination; D019444:Vaccines, DNA
chemical_list: D019013:CD40 Antigens; D000939:Epitopes; D000949:Histocompatibility Antigens Class II; D007127:Immunoglobulin Constant Regions; D007143:Immunoglobulin Heavy Chains; D011993:Recombinant Fusion Proteins; D019444:Vaccines, DNA