title: Optimization of CD4+ T lymphocyte response to human cytomegalovirus nuclear IE1 protein through modifications of both size and cellular localization.
abstract: We have previously reported that the CD4+ T lymphocyte response against nuclear human CMV IE1 protein depends in part on endogenous MHC class II presentation. To optimize presentation by HLA-DR of the nuclear IE1 protein and increase the response by CD4+ T cells, we have constructed two different adenovirus vectors containing mutant versions of IE1, containing a HLA-DR3 epitope, fused to GFP. The first construct consisted of a sequence of 46 aa encoded by exon 4, called GFP-IE1 (86-131). The second construct consisted of the whole IE1 mutated on exon 4 nuclear localization signals, identified in this study, and deleted of already known exon 2 nuclear localization signals (GFP-IE1M). Both of these IE1 vectors expressed proteins with cytoplasmic localization, as evidenced by GFP expression, as opposed to control GFP-IE1, which was nuclear. GFP-IE1 (86-131) induced IE1-specific CD4+ T cell clone response that was >30-fold more potent than that against GFP-IE1 and GFP-IE1M. The CD4+ T cell response was due to endogenous presentation followed by exogenous presentation at later time points. Presentation was dependent on both proteasome and acidic compartments. GFP-IE1 (86-131) was rapidly degraded by the APC, which may account for better presentation. Our data show potentiation of the CD4+ T cell response to a specific epitope through shortening and relocation of an otherwise nuclear protein and suggest applications in vaccination.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale Unité 563, Centre de Physiopathologie de Toulouse Purpan, Toulouse, France.
authors.forename: Sandra
authors.initials: S
authors.lastname: Delmas
authors.forename: Laurence
authors.initials: L
authors.lastname: Martin
authors.forename: Michel
authors.initials: M
authors.lastname: Baron
authors.forename: Jay A
authors.initials: JA
authors.lastname: Nelson
authors.forename: Daniel N
authors.initials: DN
authors.lastname: Streblow
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Davignon
mesh_terms: D017951:Antigen Presentation; D001483:Base Sequence; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002451:Cell Compartmentation; D002460:Cell Line; D002467:Cell Nucleus / Q000821:virology; D003587:Cytomegalovirus / Q000235:genetics / Q000276:immunology*; D003593:Cytoplasm / Q000821:virology; D004279:DNA, Viral / Q000235:genetics; D000939:Epitopes / Q000737:chemistry / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D015803:HLA-DR3 Antigen / Q000378:metabolism; D006801:Humans; D017874:Immediate-Early Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D019913:Nuclear Localization Signals / Q000235:genetics; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*
chemical_list: D004279:DNA, Viral; D000939:Epitopes; D015803:HLA-DR3 Antigen; C088645:IE1 protein, cytomegalovirus; D017874:Immediate-Early Proteins; D019913:Nuclear Localization Signals; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; D049452:Green Fluorescent Proteins; D046988:Proteasome Endopeptidase Complex