title: CD4+ T Cells Recognizing PE/PPE Antigens Directly or via Cross Reactivity Are Protective against Pulmonary Mycobacterium tuberculosis Infection.
abstract: Mycobacterium tuberculosis (Mtb), possesses at least three type VII secretion systems, ESX-1, -3 and -5 that are actively involved in pathogenesis and host-pathogen interaction. We recently showed that an attenuated Mtb vaccine candidate (Mtb Δppe25-pe19), which lacks the characteristic ESX-5-associated pe/ppe genes, but harbors all other components of the ESX-5 system, induces CD4+ T-cell immune responses against non-esx-5-associated PE/PPE protein homologs. These T cells strongly cross-recognize the missing esx-5-associated PE/PPE proteins. Here, we characterized the fine composition of the functional cross-reactive Th1 effector subsets specific to the shared PE/PPE epitopes in mice immunized with the Mtb Δppe25-pe19 vaccine candidate. We provide evidence that the Mtb Δppe25-pe19 strain, despite its significant attenuation, is comparable to the WT Mtb strain with regard to: (i) its antigenic repertoire related to the different ESX systems, (ii) the induced Th1 effector subset composition, (iii) the differentiation status of the Th1 cells induced, and (iv) its particular features at stimulating the innate immune response. Indeed, we found significant contribution of PE/PPE-specific Th1 effector cells in the protective immunity against pulmonary Mtb infection. These results offer detailed insights into the immune mechanisms underlying the remarkable protective efficacy of the live attenuated Mtb Δppe25-pe19 vaccine candidate, as well as the specific potential of PE/PPE proteins as protective immunogens.
authors.affiliation: Institut Pasteur, Unité de Pathogénomique Mycobactérienne Intégrée, Paris, France.
authors.forename: Fadel
authors.initials: F
authors.lastname: Sayes
authors.affiliation: Institut Pasteur, Unité de Pathogénomique Mycobactérienne Intégrée, Paris, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Pawlik
authors.affiliation: Institut Pasteur, Unité de Pathogénomique Mycobactérienne Intégrée, Paris, France.
authors.forename: Wafa
authors.initials: W
authors.lastname: Frigui
authors.affiliation: Institut Pasteur, Unité de Pathogénomique Mycobactérienne Intégrée, Paris, France.
authors.forename: Matthias I
authors.initials: MI
authors.lastname: Gröschel
authors.affiliation: Institut Pasteur, Unité de Pathogénomique Mycobactérienne Intégrée, Paris, France.
authors.forename: Samuel
authors.initials: S
authors.lastname: Crommelynck
authors.affiliation: Institut Pasteur, Unité de Régulation Immunitaire et Vaccinologie, Paris, France.|INSERM U1041, Paris, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Fayolle
authors.affiliation: London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Felipe
authors.initials: F
authors.lastname: Cia
authors.affiliation: London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Bancroft
authors.affiliation: University of Pisa, Ricerca Traslazionale e delle Nuove Tecnologie in Medicina e Chirurgia, Pisa, Italy.
authors.forename: Daria
authors.initials: D
authors.lastname: Bottai
authors.affiliation: Institut Pasteur, Unité de Régulation Immunitaire et Vaccinologie, Paris, France.|INSERM U1041, Paris, France.
authors.forename: Claude
authors.initials: C
authors.lastname: Leclerc
authors.affiliation: Institut Pasteur, Unité de Pathogénomique Mycobactérienne Intégrée, Paris, France.
authors.forename: Roland
authors.initials: R
authors.lastname: Brosch
authors.affiliation: Institut Pasteur, Unité de Pathogénomique Mycobactérienne Intégrée, Paris, France.
authors.forename: Laleh
authors.initials: L
authors.lastname: Majlessi
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D003429:Cross Reactions; D004195:Disease Models, Animal; D005260:Female; D005434:Flow Cytometry; D051379:Mice; D008810:Mice, Inbred C57BL; D009169:Mycobacterium tuberculosis / Q000276:immunology; D018417:Th1 Cells; D032581:Tuberculosis Vaccines / Q000276:immunology*; D014397:Tuberculosis, Pulmonary / Q000276:immunology*
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C582018:PPE2 protein, Mycobacterium tuberculosis; D032581:Tuberculosis Vaccines