title: Characterization of host immunity to cytomegalovirus pp150 (UL32).
abstract: The basic phosphoprotein 150 (pp150), the product of UL32 (unique long domain 32) gene of human cytomegalovirus (CMV), is an abundant component of the viral tegument and a target of human leukocyte antigen (HLA)-restricted cytotoxic T cells (CTLs) after infection. Identification of minimal cytotoxic epitopes (MCEs) from this CMV protein is of importance for peptide-based vaccines and immunotherapeutic approaches. Several pp150-specific CTL clones were derived from peripheral blood mononuclear cells of healthy CMV-positive donors with autologous fibroblasts infected either with CMV AD169 or with a recombinant vaccinia virus expressing full-length pp150 protein. HLA A*0301- and HLA A*6801-restricted CD8+ pp150 T-cell clones derived from different donors were found to efficiently kill autologous CMV-infected fibroblasts. Fine mapping of each MCE first used a T-cell epitope prediction algorithm. Overlapping peptides within the recognized regions were screened. The analysis identified pp150(792-802) and pp150(945-955) as MCEs for the HLA A*6801 and the HLA A*0301 pp150 clones, respectively. In vitro stimulation by recombinant modified vaccinia Ankara virus expressing full-length pp150 elicited high frequencies of CMV-CTL and interferon gamma production specific for the MCE identified in all subjects. The consistent presence of pp150 T cells in CMV-exposed individuals supports a role for this antigen in shaping the antiviral CTL response and indicates that pp150 could be a pivotal constituent of prophylactic and therapeutic CMV vaccines.
authors.affiliation: Laboratory of Vaccine Research, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA.
authors.forename: Corinna
authors.initials: C
authors.lastname: La Rosa
authors.forename: Zhongde
authors.initials: Z
authors.lastname: Wang
authors.forename: Simon F
authors.initials: SF
authors.lastname: Lacey
authors.forename: Susan F
authors.initials: SF
authors.lastname: Markel
authors.forename: Madeva C
authors.initials: MC
authors.lastname: Sharma
authors.forename: Joybelle
authors.initials: J
authors.lastname: Martinez
authors.forename: Maria M
authors.initials: MM
authors.lastname: Lalimarmo
authors.forename: Don J
authors.initials: DJ
authors.lastname: Diamond
mesh_terms: D002999:Clone Cells; D003587:Cytomegalovirus / Q000276:immunology; D003586:Cytomegalovirus Infections / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D018604:Epitope Mapping; D006680:HLA Antigens / Q000276:immunology; D006801:Humans; D010750:Phosphoproteins / Q000235:genetics* / Q000276:immunology*; D016693:Receptors, Antigen, T-Cell, alpha-beta; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology / Q000821:virology*; D019444:Vaccines, DNA / Q000276:immunology*; D014616:Vaccinia virus; D014763:Viral Matrix Proteins / Q000235:genetics* / Q000276:immunology*
chemical_list: D006680:HLA Antigens; D010750:Phosphoproteins; D016693:Receptors, Antigen, T-Cell, alpha-beta; D019444:Vaccines, DNA; D014763:Viral Matrix Proteins; C056367:pp150 protein, Cytomegalovirus