title: Approach to discover T- and B-cell antigens of intracellular pathogens applied to the design of Chlamydia trachomatis vaccines.
abstract: Natural immunity against obligate and/or facultative intracellular pathogens is usually mediated by both humoral and cellular immunity. The identification of those antigens stimulating both arms of the immune system is instrumental for vaccine discovery. Although high-throughput technologies have been applied for the discovery of antibody-inducing antigens, few examples of their application for T-cell antigens have been reported. We describe how the compilation of the immunome, here defined as the pool of immunogenic antigens inducing T- and B-cell responses in vivo, can lead to vaccine candidates against Chlamydia trachomatis. We selected 120 C. trachomatis proteins and assessed their immunogenicity using two parallel high-throughput approaches. Protein arrays were generated and screened with sera from C. trachomatis-infected patients to identify antibody-inducing antigens. Splenocytes from C. trachomatis-infected mice were stimulated with 79 proteins, and the frequency of antigen-specific CD4(+)/IFN-γ(+) T cells was analyzed by flow cytometry. We identified 21 antibody-inducing antigens, 16 CD4(+)/IFN-γ(+)-inducing antigens, and five antigens eliciting both types of responses. Assessment of their protective activity in a mouse model of Chlamydia muridarum lung infection led to the identification of seven antigens conferring partial protection when administered with LTK63/CpG adjuvant. Protection was largely the result of cellular immunity as assessed by CD4(+) T-cell depletion. The seven antigens provided robust additive protection when combined in four-antigen combinations. This study paves the way for the development of an effective anti-Chlamydia vaccine and provides a general approach for the discovery of vaccines against other intracellular pathogens.
authors.affiliation: Novartis Vaccines and Diagnostics, 53100 Siena, Italy.
authors.forename: Oretta
authors.initials: O
authors.lastname: Finco
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Frigimelica
authors.forename: Francesca
authors.initials: F
authors.lastname: Buricchi
authors.forename: Roberto
authors.initials: R
authors.lastname: Petracca
authors.forename: Giuliano
authors.initials: G
authors.lastname: Galli
authors.forename: Elisa
authors.initials: E
authors.lastname: Faenzi
authors.forename: Eva
authors.initials: E
authors.lastname: Meoni
authors.forename: Alessandra
authors.initials: A
authors.lastname: Bonci
authors.forename: Mauro
authors.initials: M
authors.lastname: Agnusdei
authors.forename: Filomena
authors.initials: F
authors.lastname: Nardelli
authors.forename: Erika
authors.initials: E
authors.lastname: Bartolini
authors.forename: Maria
authors.initials: M
authors.lastname: Scarselli
authors.forename: Elena
authors.initials: E
authors.lastname: Caproni
authors.forename: Donatello
authors.initials: D
authors.lastname: Laera
authors.forename: Luisanna
authors.initials: L
authors.lastname: Zedda
authors.forename: David
authors.initials: D
authors.lastname: Skibinski
authors.forename: Serena
authors.initials: S
authors.lastname: Giovinazzi
authors.forename: Riccardo
authors.initials: R
authors.lastname: Bastone
authors.forename: Elvira
authors.initials: E
authors.lastname: Ianni
authors.forename: Roberto
authors.initials: R
authors.lastname: Cevenini
authors.forename: Guido
authors.initials: G
authors.lastname: Grandi
authors.forename: Renata
authors.initials: R
authors.lastname: Grifantini
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology; D000942:Antigens, Bacterial / Q000276:immunology* / Q000378:metabolism; D001402:B-Lymphocytes / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology / Q000378:metabolism; D001428:Bacterial Vaccines / Q000276:immunology* / Q000627:therapeutic use; D015153:Blotting, Western; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D002460:Cell Line; D002690:Chlamydia Infections / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control; D023502:Chlamydia muridarum / Q000276:immunology; D002692:Chlamydia trachomatis / Q000276:immunology* / Q000378:metabolism; D005260:Female; D006367:HeLa Cells; D006801:Humans; D007106:Immune Sera / Q000276:immunology; D007114:Immunization; D007371:Interferon-gamma / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D018613:Microscopy, Confocal; D013601:T-Lymphocytes / Q000276:immunology*; D018417:Th1 Cells / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D001428:Bacterial Vaccines; D007106:Immune Sera; D007371:Interferon-gamma