title: Immunization with hybrid recombinant Mycobacterium tuberculosis H37Rv proteins increases the TH1 cytokine response in mice following a pulmonary instillation of irradiated mycobacteria.
abstract: The aim of this research was to identify subunit immunogens that can generate enhanced CD8 T cell and TH1 responses against Mycobacterium tuberculosis. A genomic comparison of the M. tuberculosis H(37)R(V) and M. bovis BCG identified 61 proteins that are unique to H(37)R(V). Further screening of these 61 proteins using in silico analyses mimicking proteasomal digestion, transporter-associated antigen processing and H-2 antigen presentation identified 13 proteins with high densities of predicted MHC class I epitopes. Two native proteins, Rv1986c and Rv3875, were selected on the basis of their secreted or transmembrane characteristics and relatively lower frequencies of predicted MHC class II epitopes. To further enhance the CD8 T cell and TH1 responses, a hybrid protein, H32, was constructed by combining the nucleotide sequences encoding the MHC class I antigen-rich segment of Rv1986c and the entire Rv3875 sequence. The two native proteins and the hybrid were used to immunize C57BL/6 and Balb/c mice, which was followed by pulmonary instillation with irradiated M. tuberculosis H(37)R(V). All three proteins elicited elevated IFN-gamma responses, with the hybrid showing significant increases over the native proteins in both mice. This strategy of immunogen selection might be used to improve the current subunit vaccines against M. tuberculosis as well as other intra-cellular pathogens.
authors.affiliation: University of Hawaii at Manoa, Department of Molecular Biosciences and Bioengineering, 1955 East-West Road, Honolulu, HI 96822, USA.
authors.forename: Chad B
authors.initials: CB
authors.lastname: Walton
authors.forename: Ana Blossom H
authors.initials: AB
authors.lastname: Inos
authors.forename: Osler A
authors.initials: OA
authors.lastname: Andres
authors.forename: Sandro
authors.initials: S
authors.lastname: Jube
authors.forename: Heinz Gert
authors.initials: HG
authors.lastname: de Couet
authors.forename: James T
authors.initials: JT
authors.lastname: Douglas
authors.forename: Paul Q
authors.initials: PQ
authors.lastname: Patek
authors.forename: Dulal
authors.initials: D
authors.lastname: Borthakur
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D016207:Cytokines / Q000096:biosynthesis*; D018984:Epitopes, T-Lymphocyte / Q000235:genetics; D008168:Lung / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D009163:Mycobacterium bovis / Q000235:genetics; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology; D018417:Th1 Cells / Q000276:immunology; D032581:Tuberculosis Vaccines / Q000235:genetics / Q000276:immunology*
chemical_list: D001426:Bacterial Proteins; D016207:Cytokines; D018984:Epitopes, T-Lymphocyte; D011993:Recombinant Fusion Proteins; D032581:Tuberculosis Vaccines