title: Targeting a polyepitope protein incorporating multiple class II-restricted viral epitopes to the secretory/endocytic pathway facilitates immune recognition by CD4+ cytotoxic T lymphocytes: a novel approach to vaccine design.
abstract: The role of CD4+ and CD8+ cells in the generation of an effective immune response against viral infections is well established. Moreover, there is an increasing realization that subunit vaccines which include both CD4+- and CD8+-T-cell epitopes are highly effective in controlling viral infections, as opposed to those which are designed to activate a CD8+- or CD4+-T-cell response alone. One of the major limitations of epitope-based vaccines designed to stimulate virus-specific CD4+ T cells is that endogenously expressed class II-restricted minimal cytotoxic-T-lymphocyte (CTL) epitopes are poorly recognized by CD4+ CTLs. In the present study we attempted to enhance the efficiency of class II-restricted endogenous presentation of minimal class II-restricted CTL epitopes by specifically targeting a polyepitope protein to class II processing compartments through the endosomal and/or lysosomal pathway. A significantly enhanced stimulation of virus-specific CD4+-T-cell clones by antigen-presenting cells (APC) expressing the recombinant polyepitope protein targeted to the endocytic/secretory pathway was readily demonstrated in cytotoxicity assays. In addition, in vitro activation of Epstein-Barr virus- and influenza virus-specific CD4+ memory CTLs by the recombinant constructs encoding the polyepitope protein, specifically targeted to the lysosomal compartment, was also demonstrated. The enhanced stimulatory capacity of APC expressing a lysosome-targeted polyepitope protein has important implications for vaccine design.
authors.affiliation: CRC for Vaccine Technology, Queensland Institute of Medical Research, The Bancroft Centre, Brisbane, Australia.
authors.forename: S A
authors.initials: SA
authors.lastname: Thomson
authors.forename: S R
authors.initials: SR
authors.lastname: Burrows
authors.forename: I S
authors.initials: IS
authors.lastname: Misko
authors.forename: D J
authors.initials: DJ
authors.lastname: Moss
authors.forename: B E
authors.initials: BE
authors.lastname: Coupar
authors.forename: R
authors.initials: R
authors.lastname: Khanna
mesh_terms: D017951:Antigen Presentation; D015703:Antigens, CD / Q000235:genetics / Q000276:immunology; D000956:Antigens, Viral / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D002461:Cell Line, Transformed; D015195:Drug Design; D004705:Endocytosis; D018984:Epitopes, T-Lymphocyte / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D005822:Genetic Vectors; D006367:HeLa Cells; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D006801:Humans; D007156:Immunologic Memory; D051907:Lysosomal Membrane Proteins; D008247:Lysosomes; D008562:Membrane Glycoproteins / Q000235:genetics / Q000276:immunology; D010446:Peptide Fragments / Q000096:biosynthesis / Q000276:immunology*; D014176:Protein Biosynthesis; D011506:Proteins / Q000276:immunology*; D014616:Vaccinia virus; D014765:Viral Vaccines
chemical_list: D015703:Antigens, CD; D000956:Antigens, Viral; D018984:Epitopes, T-Lymphocyte; D000949:Histocompatibility Antigens Class II; D051907:Lysosomal Membrane Proteins; D008562:Membrane Glycoproteins; D010446:Peptide Fragments; D011506:Proteins; D014765:Viral Vaccines