title: Metabolic engineering of Salmonella vaccine bacteria to boost human Vγ2Vδ2 T cell immunity.
abstract: Human Vγ2Vδ2 T cells monitor isoprenoid metabolism by recognizing foreign (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMBPP), a metabolite in the 2-C-methyl-D-erythritol-4-phosphate pathway used by most eubacteria and apicomplexan parasites, and self isopentenyl pyrophosphate, a metabolite in the mevalonate pathway used by humans. Whereas microbial infections elicit prolonged expansion of memory Vγ2Vδ2 T cells, immunization with prenyl pyrophosphates or aminobisphosphonates elicit short-term Vγ2Vδ2 expansion with rapid anergy and deletion upon subsequent immunizations. We hypothesized that a live, attenuated bacterial vaccine that overproduces HMBPP would elicit long-lasting Vγ2Vδ2 T cell immunity by mimicking a natural infection. Therefore, we metabolically engineered the avirulent aroA(-) Salmonella enterica serovar Typhimurium SL7207 strain by deleting the gene for LytB (the downstream enzyme from HMBPP) and functionally complementing for this loss with genes encoding mevalonate pathway enzymes. LytB(-) Salmonella SL7207 had high HMBPP levels, infected human cells as efficiently as did the wild-type bacteria, and stimulated large ex vivo expansions of Vγ2Vδ2 T cells from human donors. Importantly, vaccination of a rhesus monkey with live lytB(-) Salmonella SL7207 stimulated a prolonged expansion of Vγ2Vδ2 T cells without significant side effects or anergy induction. These studies provide proof-of-principle that metabolic engineering can be used to derive live bacterial vaccines that boost Vγ2Vδ2 T cell immunity. Similar engineering of metabolic pathways to produce lipid Ags or B vitamin metabolite Ags could be used to derive live bacterial vaccine for other unconventional T cells that recognize nonpeptide Ags.
authors.affiliation: Division of Immunology, Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA 52242; Department of Veterans Affairs, Iowa City Health Care System, Iowa City, IA 52246;
authors.forename: Grefachew
authors.initials: G
authors.lastname: Workalemahu
authors.affiliation: Division of Immunology, Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA 52242; Department of Veterans Affairs, Iowa City Health Care System, Iowa City, IA 52246;
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.affiliation: Division of Immunology, Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA 52242; Singapore Immunology Network, Agency for Science, Technology and Research, Singapore 138648;
authors.forename: Kia-Joo
authors.initials: KJ
authors.lastname: Puan
authors.affiliation: Division of Immunology, Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA 52242; Department of Veterans Affairs, Iowa City Health Care System, Iowa City, IA 52246; Interdisciplinary Graduate Program in Immunology, University of Iowa Carver College of Medicine, Iowa City, IA 52242;
authors.forename: Mohanad H
authors.initials: MH
authors.lastname: Nada
authors.affiliation: Biotechnology Research Center, The University of Tokyo, Tokyo 113-8657, Japan;
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Kuzuyama
authors.affiliation: Department of Microbiology, University of Iowa Carver College of Medicine, Iowa City, IA 52242; Interdisciplinary Graduate Program in Genetics, University of Iowa Carver College of Medicine, Iowa City, IA 52242; and Inflammation Program, University of Iowa Carver College of Medicine, Iowa City, IA 52242.
authors.forename: Bradley D
authors.initials: BD
authors.lastname: Jones
authors.affiliation: Division of Immunology, Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA 52242; Department of Veterans Affairs, Iowa City Health Care System, Iowa City, IA 52246;
authors.forename: Chenggang
authors.initials: C
authors.lastname: Jin
authors.affiliation: Division of Immunology, Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA 52242; Department of Veterans Affairs, Iowa City Health Care System, Iowa City, IA 52246; Interdisciplinary Graduate Program in Immunology, University of Iowa Carver College of Medicine, Iowa City, IA 52242; Craig-Morita@uiowa.edu.
authors.forename: Craig T
authors.initials: CT
authors.lastname: Morita
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D049109:Cell Proliferation; D002478:Cells, Cultured; D017353:Gene Deletion; D006801:Humans; D007114:Immunization; D008213:Lymphocyte Activation / Q000276:immunology; D008253:Macaca mulatta / Q000276:immunology; D060847:Metabolic Engineering / Q000379:methods*; D053858:Metabolic Networks and Pathways / Q000235:genetics / Q000276:immunology; D008798:Mevalonic Acid / Q000378:metabolism; D010755:Organophosphates / Q000378:metabolism; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000276:immunology* / Q000378:metabolism; D022562:Salmonella Vaccines / Q000276:immunology*; D012486:Salmonella typhimurium / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism
chemical_list: C467061:4-hydroxy-3-methyl-2-butenyl diphosphate; D001426:Bacterial Proteins; D010755:Organophosphates; D016692:Receptors, Antigen, T-Cell, gamma-delta; D022562:Salmonella Vaccines; D008798:Mevalonic Acid