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Toxoplasma gondii is an obligate intracellular parasite that is the etiologic agent responsible for toxoplasmosis. Infection with T. gondii results in activation of nucleotide binding domain and leucine rich repeat containing receptors (NLRs). NLR activation leads to inflammasome formation, the activation of caspase-1, and the subsequent cleavage of IL-1β and IL-18. Recently, a noncanonical inflammasome has been characterized which functions through caspase-11 and appears to augment many biological functions previously considered to be dependent upon the canonical inflammasome. To better elucidate the function of this noncanonical inflammasome in toxoplasmosis, we utilized Asc−/− and Casp11−/− mice and infected these animals with T. gondii. Our data indicates that caspase-11 modulates the innate immune response to T. gondii through a mechanism which is distinct from that currently described for the canonical inflammasome. Asc−/− mice demonstrated increased disease pathogenesis during the acute phase of T. gondii infection, whereas Casp11−/− mice demonstrated significantly attenuated disease pathogenesis and reduced inflammation. This attenuated host response was associated with reduced local and systemic cytokine production, including diminished IL-1β. During the chronic phase of infection, caspase-11 deficiency resulted in increased neuroinflammation and tissue cyst burden in the brain. Together, our data suggest that caspase-11 functions to protect the host by enhancing inflammation during the early phase of infection in an effort to minimize disease pathogenesis during later stages of toxoplasmosis.

The mechanism by which type II interferon (IFN) inhibits virus replications remains to be identified. Murine leukemia virus (MLV) replication was significantly restricted by γ-IFN, but not human immunodeficiency virus type 1 (HIV-1) replication. Because MLV enters host cells via endosomes, we speculated that certain cellular factors among γ-IFN-induced, endosome-localized proteins inhibit MLV replication. We found that γ-IFN-inducible lysosomal thiolreductase (GILT) significantly restricts HIV-1 replication as well as MLV replication by its thiolreductase activity. GILT silencing enhanced replication-defective HIV-1 vector infection and virion production in γ-IFN-treated cells, although γ-IFN did not inhibit HIV-1 replication. This result showed that GILT is required for the anti-viral activity of γ-IFN. Interestingly, GILT protein level was increased by γ-IFN in uninfected cells and env-deleted HIV-1-infected cells, but not in full-length HIV-1-infected cells. γ-IFN-induced transcription from the γ-IFN-activation sequence was attenuated by the HIV-1 Env protein. These results suggested that the γ-IFN cannot restrict HIV-1 replication due to the inhibition of γ-IFN signaling by HIV-1 Env. Finally, we found that 4,4’-dithiodipyridine (4-PDS), which inhibits S-S bond formation at acidic pH, significantly suppresses HIV-1 vector infection and virion production, like GILT. In conclusion, this study showed that GILT functions as a host restriction factor against the retroviruses, and a GILT mimic, 4-PDS, is the leading compound for the development of novel concept of anti-viral agents.

Les tècniques dels IGRAs (Interferon-gamma release assays) Quantiferon-TB Gold in Tube (QFN-G-IT) així com el T-SPOT.TB, quantifiquen la resposta cel·lular immune a través de la detecció de l' Interferó-gamma (IF-γ) produït per les cèl·lules T sensibilitzades prèviament, en resposta a una estimulació in vitro amb antígens específics: l'ESAT-6, CFP-10 i TB7.7, que estan presents al M. tuberculosis complex, però absents en el bacil vacunal BCG i la majoria de les micobactèries no tuberculoses. L'objectiu d'aquesta Tesi Doctoral és comparar la utilitat clínica d'aquestes tècniques amb la prova de la tuberculina (PT) en diferents situacions. 1er Estudi: Avaluar la positivitat del QFN-G-IT i el T-SPOT.TB en adults amb Tuberculosi (TB) activa. La sensibilitat global en els casos amb confirmació microbiològica va ser del 75,9% utilitzant T-SPOT.TB i del 58,2% amb QFN-G-IT. En els pacients inclosos en l'inici del tractament, la sensibilitat per a T-SPOT.TB va ser del 83,3% i del 69,4% per QFN-G-IT. Per contra, en els pacients avaluats durant el tractament, la sensibilitat va ser del 69,8% per a T-SPOT.TB i 48,8% per QFN-G-IT. 2n Estudi: Avaluar els IGRAs i la PT en el diagnòstic de la Infecció Tuberculosa (IT) en nens reclutats en estudis de contacte i cribratges de salut públics. La concordança entre la PT i els IGRAs va ser alta en els nens no vacunats amb BCG. Les variables associades amb resultats discordants van ser: pertànyer al grup de cribratge (OR ajustada = 6,9; 95% CI = 3.4-14.4; p 0,001); ser vacunats amb BCG (OR ajustada = 10,1; IC del 95% = 3.3-30.9; p 0,001); i PT entre 5-9 mm (OR ajustada = 10,4; IC del 95% = 3.5-31.1; p 6 h en comparació amb els de 6 hores d'exposició . L'amuntegament no es va associar amb la positivitat de cap de les proves. La positivitat de la PT no es va correlacionar amb els factors de risc estudiats: tos, retard diagnòstic; mida de l'habitació; amuntegament. Tanmateix, ambdós IGRAs van mostrar una associació significativa amb la presè, Interferon-γ (IF-γ) release assays (IGRAs), Quantiferon-TB Gold in Tube (QFN-G-IT) as well as T-SPOT.TB quantify the cellular immune response by detecting IF-γ, produced by T-cells sensitized previously, in response to in vitro stimulation with specific antigens: ESAT-6, CFP-10 and TB7.7 which are present in M. tuberculosis complex but absent in BCG vaccine strain and most environmental mycobacteria. The purpose of this Doctoral Thesis is to test and compare the clinical utility of both IGRA techniques and TST in different situations. 1st Study: To assess the positivity of QFN-G-IT and T-SPOT.TB test in adult patients with active tuberculosis (TB). The overall sensitivity in microbiologically confirmed patients was 75.9% using T-SPOT.TB and 58.2% using QFN-G-IT. In patients included at the beginning of the treatment, the sensitivity for T-SPOT.TB was 83.3% and 69.4% for QFN-G-IT. In contrast, in patients evaluated during treatment, the sensitivity was 69.8% for T-SPOT.TB and 48.8% for QFN-G-IT. 2nStudy: To evaluate IGRAs and TST in diagnosing TB infection in children, recruited from contact-tracing studies and from public health screenings. The agreement between TST and IFN-γ-tests was high in non-BCG-vaccinated children. Variables associated with discordant results were: belonging to the screening group (adjusted OR=6.9; 95%CI=3.4.14.4; p 0.001); being vaccinated with BCG (adjusted OR=10.1; 95%CI=3.3.30.9; p 0.001); and TST between 5-9 mm (adjusted OR=10.4; 95%CI=3.5.31.1; p 6 h of exposure, in comparison to the contacts with 6 h of exposure. Overcrowding was not associated with the positivity of any of the tests. The TST positivity was not correlated with any risk factors: cough; delayed diagnosis; room size; overcrowding. However both IGRAs associated better than TST with cough and the size of the room where contact was made. The results of all the studies presented in this doctoral thesis show that the new laboratory methods for the immunodiagnosis of latent tub

Background: Infection with the Gram-negative bacterium Burkholderia pseudomallei is an important cause of community-acquired lethal sepsis in endemic regions in southeast Asia and northern Australia and is increasingly reported in other tropical areas. In animal models, production of interferon-gamma (IFN-gamma) is critical for resistance, but in humans the characteristics of IFN-gamma production and the bacterial antigens that are recognized by the cell-mediated immune response have not been defined. Methods: Peripheral blood from 133 healthy individuals who lived in the endemic area and had no history of melioidosis, 60 patients who had recovered from melioidosis, and 31 other patient control subjects were stimulated by whole bacteria or purified bacterial proteins in vitro, and IFN-gamma responses were analyzed by ELISPOT and flow cytometry. Findings: B. pseudomallei was a potent activator of human peripheral blood NK cells for innate production of IFN-gamma. In addition, healthy individuals with serological evidence of exposure to B. pseudomallei and patients recovered from active melioidosis developed CD4(+) (and CD8(+)) T cells that recognized whole bacteria and purified proteins LolC, OppA, and PotF, members of the B. pseudomallei ABC transporter family. This response was primarily mediated by terminally differentiated T cells of the effector-memory (T(EMRA)) phenotype and correlated with the titer of anti-B. pseudomallei antibodies in the serum. Conclusions: Individuals living in a melioidosis-endemic region show clear evidence of T cell priming for the ability to make IFN-gamma that correlates with their serological status. The ability to detect T cell responses to defined B. pseudomallei proteins in large numbers of individuals now provides the opportunity to screen candidate antigens for inclusion in protein or polysaccharide-conjugate subunit vaccines against this important but neglected disease.

Background: Infection with the Gram-negative bacterium Burkholderia pseudomallei is an important cause of community-acquired lethal sepsis in endemic regions in southeast Asia and northern Australia and is increasingly reported in other tropical areas. In animal models, production of interferon-gamma (IFN-gamma) is critical for resistance, but in humans the characteristics of IFN-gamma production and the bacterial antigens that are recognized by the cell-mediated immune response have not been defined. Methods: Peripheral blood from 133 healthy individuals who lived in the endemic area and had no history of melioidosis, 60 patients who had recovered from melioidosis, and 31 other patient control subjects were stimulated by whole bacteria or purified bacterial proteins in vitro, and IFN-gamma responses were analyzed by ELISPOT and flow cytometry. Findings: B. pseudomallei was a potent activator of human peripheral blood NK cells for innate production of IFN-gamma. In addition, healthy individuals with serological evidence of exposure to B. pseudomallei and patients recovered from active melioidosis developed CD4(+) (and CD8(+)) T cells that recognized whole bacteria and purified proteins LolC, OppA, and PotF, members of the B. pseudomallei ABC transporter family. This response was primarily mediated by terminally differentiated T cells of the effector-memory (T(EMRA)) phenotype and correlated with the titer of anti-B. pseudomallei antibodies in the serum. Conclusions: Individuals living in a melioidosis-endemic region show clear evidence of T cell priming for the ability to make IFN-gamma that correlates with their serological status. The ability to detect T cell responses to defined B. pseudomallei proteins in large numbers of individuals now provides the opportunity to screen candidate antigens for inclusion in protein or polysaccharide-conjugate subunit vaccines against this important but neglected disease.

To evaluate in routine hospital practice the clinical response to ertapenem in comparison with other parenteral antibiotics in the treatment of community-acquired pneumonia (CAP), clinical records from patients with severe CAP treated with ertapenem from July 2002 to June 2006 in seven Spanish hospitals were retrospectively reviewed. Patients were classified according to the Pneumonia Severity Index (PSI). Each ertapenem-treated patient was matched with two patients in the same hospital treated with other antibiotics, according to age (difference 76 years). Comorbidities were present in 193 patients (95.5%). No differences were found in median hospital stay (7 days for ertapenem vs. 10 days for comparators, p 0.066). A slightly higher clinical response rate was obtained for ertapenem vs. comparators (88.7% vs. 77.1%; p 0.0465; OR 2.25; 95% CI 0.99-5.12), with significant differences in clinical response in patients coming from nursing homes (95.8% ertapenem vs. 63.8% comparators; p 0.0034) but not in non-institutionalized patients (85.4% ertapenem vs. 84.5% comparators; p 0.929). The higher clinical response to ertapenem vs. comparators in severe CAP was due to its significantly higher efficacy in healthcare-associated CAP in patients coming from nursing homes.

Das Ubiquitin-Proteasom-System sorgt in eukaryontischen Zellen für einen kontrollierten Abbau von Proteinen. Das 20S Proteasom ist als Multikatalytischer Protease Komplex der zentrale Bestandteil dieses Systems. In der vorliegenden Arbeit konnte gezeigt werden, dass sich gereinigtes 20S Proteasom aus HeLa-Zellen chromatographisch in Subtypen auftrennen lässt, die sich strukturell und in ihrer proteolytischen Aktivität unterscheiden. Nach Induktion der Zellen mit gamma-Interferon (gamma-IFN) werden Immuno-Proteasomen gebildet und es kommt zu einer Veränderung des Subtypen-Musters und der Aktivitäten. Unter dem Einfluss von gamma-IFN bilden sich hauptsächlich Mischkomplexe mit sowohl konstitutiven als auch Immuno-Untereinheiten. Weiterhin konnte gezeigt werden, dass in den Zellkompartimenten Cytoplasma, Zellkern und Microsomen von HeLaS3-Zellen unterschiedliche 20S Proteasom-Subtypen vorkommen. Dies war unter anderem auf eine unterschiedliche Glykosylierung einzelner proteasomaler Untereinheiten zurückzuführen. Die genaue Kenntnis von Struktur und Funktion der 20S Proteasom-Subtypen ist im Hinblick auf neue diagnostische und therapeutische Ansätze in der Humanmedizin von großem Interesse., The Ubiquitin-proteasome system is responsible for the regulated protein degradation in eucaryotic cells. The 20S proteasome is as a multicatalytic protease the central complex of these system. This study has shown that it is possible to separate 20S proteasome subtypes from HeLa cells by chromatography. 20s proteasome subtypes differ in structure and proteolytic activity. The subtype-pattern and the activity are significantly changed after an induction of the cells with gamma-Interferon (gamma-IFN) under formation of immuno proteasomes. After gamma-IFN induction mainly mixed complexes have been formed with both constitutive and immuno subunits. Further it has been shown that in cell compartements cytoplasm, microsomes and nucleus of HeLaS3 cells different 20S proteasome subtypes are located. Among other things glycosylation of some subunits is responsible for that phenomenon. With regard to new strategies in diagnostic and therapy of human diseases the exactly knowledge of structure and function of the proteasome subtypes is a case of interest.

Psoriasis ist eine komplexe entzündliche Erkrankung der Haut. Charakteristisch ist eine dichte Infiltration von T-Lymphozyten und eine Hyperproliferation der Epithelschicht. Heutzutage belegen die Ergebnisse vieler experimteller Studien, daß Psoriasis eine T-Zell-induzierte Erkrankung ist. Die Spezifität der T-Zell-stimulierenden Antigene ist noch unbekannt. Voraussetzung für die Charakterisierung psoriatischer T-Zellen ist die Isolation von T-Zell-Klonen aus psoriatischen Plaques, deren Restimulation in vitro qualitativ und quantitativ erfaßbar ist. Hierfür haben wir einen hochsensiblen gamma-Interferon Elispot-Assay etabiert, der die Aktivität der T-Zellen aus Hautplaques erfaßt. Zudem zeigen wir, daß man aktivierte T-Zell-Klone mittels CD25-Markierung isolieren und anschließend klonieren kann. Unsere Ergebnisse können als eine Grundlage für weitere Versuche dienen, die die Spezifität von T-Zell-Klonen aus psoriatischen Plaques charakterisieren sollen., Psoriasis is a complex inflammatory disease of the skin characterized by a dense infiltration of T-lymphocytes and a hyperproliferation of the epithelial layer. A host of experimental and clinical data suggest that psoriasis is a T cell mediated disorder. The nature of T-cell-stimulating antigens is still unknown. One way to identify putative antigen(s) is the definition of T-cell-receptor specifities using randomized combinatorial peptide libraries. This requires the isolation and expansion of T cell clones from psoriatic plaques in vitro. Therefore we established a gamma-interferon Elispot-assay which allows quantification of the frequency of activated plaque-derived T cells in vitro. In addition, we show that activated T cell clones can be sorted via CD25 and cloned. The expanded clones can also be restimulated by autologous cells. Our results should be useful in the design of experiments aiming at a systematic analysis of the specifity of T cell clones present in psoriatic plaques.

Psoriasis ist eine komplexe entzündliche Erkrankung der Haut. Charakteristisch ist eine dichte Infiltration von T-Lymphozyten und eine Hyperproliferation der Epithelschicht. Heutzutage belegen die Ergebnisse vieler experimteller Studien, daß Psoriasis eine T-Zell-induzierte Erkrankung ist. Die Spezifität der T-Zell-stimulierenden Antigene ist noch unbekannt. Voraussetzung für die Charakterisierung psoriatischer T-Zellen ist die Isolation von T-Zell-Klonen aus psoriatischen Plaques, deren Restimulation in vitro qualitativ und quantitativ erfaßbar ist. Hierfür haben wir einen hochsensiblen gamma-Interferon Elispot-Assay etabiert, der die Aktivität der T-Zellen aus Hautplaques erfaßt. Zudem zeigen wir, daß man aktivierte T-Zell-Klone mittels CD25-Markierung isolieren und anschließend klonieren kann. Unsere Ergebnisse können als eine Grundlage für weitere Versuche dienen, die die Spezifität von T-Zell-Klonen aus psoriatischen Plaques charakterisieren sollen., Psoriasis is a complex inflammatory disease of the skin characterized by a dense infiltration of T-lymphocytes and a hyperproliferation of the epithelial layer. A host of experimental and clinical data suggest that psoriasis is a T cell mediated disorder. The nature of T-cell-stimulating antigens is still unknown. One way to identify putative antigen(s) is the definition of T-cell-receptor specifities using randomized combinatorial peptide libraries. This requires the isolation and expansion of T cell clones from psoriatic plaques in vitro. Therefore we established a gamma-interferon Elispot-assay which allows quantification of the frequency of activated plaque-derived T cells in vitro. In addition, we show that activated T cell clones can be sorted via CD25 and cloned. The expanded clones can also be restimulated by autologous cells. Our results should be useful in the design of experiments aiming at a systematic analysis of the specifity of T cell clones present in psoriatic plaques.

Das Ubiquitin-Proteasom-System sorgt in eukaryontischen Zellen für einen kontrollierten Abbau von Proteinen. Das 20S Proteasom ist als Multikatalytischer Protease Komplex der zentrale Bestandteil dieses Systems. In der vorliegenden Arbeit konnte gezeigt werden, dass sich gereinigtes 20S Proteasom aus HeLa-Zellen chromatographisch in Subtypen auftrennen lässt, die sich strukturell und in ihrer proteolytischen Aktivität unterscheiden. Nach Induktion der Zellen mit gamma-Interferon (gamma-IFN) werden Immuno-Proteasomen gebildet und es kommt zu einer Veränderung des Subtypen-Musters und der Aktivitäten. Unter dem Einfluss von gamma-IFN bilden sich hauptsächlich Mischkomplexe mit sowohl konstitutiven als auch Immuno-Untereinheiten. Weiterhin konnte gezeigt werden, dass in den Zellkompartimenten Cytoplasma, Zellkern und Microsomen von HeLaS3-Zellen unterschiedliche 20S Proteasom-Subtypen vorkommen. Dies war unter anderem auf eine unterschiedliche Glykosylierung einzelner proteasomaler Untereinheiten zurückzuführen. Die genaue Kenntnis von Struktur und Funktion der 20S Proteasom-Subtypen ist im Hinblick auf neue diagnostische und therapeutische Ansätze in der Humanmedizin von großem Interesse., The Ubiquitin-proteasome system is responsible for the regulated protein degradation in eucaryotic cells. The 20S proteasome is as a multicatalytic protease the central complex of these system. This study has shown that it is possible to separate 20S proteasome subtypes from HeLa cells by chromatography. 20s proteasome subtypes differ in structure and proteolytic activity. The subtype-pattern and the activity are significantly changed after an induction of the cells with gamma-Interferon (gamma-IFN) under formation of immuno proteasomes. After gamma-IFN induction mainly mixed complexes have been formed with both constitutive and immuno subunits. Further it has been shown that in cell compartements cytoplasm, microsomes and nucleus of HeLaS3 cells different 20S proteasome subtypes are located. Among other things glycosylation of some subunits is responsible for that phenomenon. With regard to new strategies in diagnostic and therapy of human diseases the exactly knowledge of structure and function of the proteasome subtypes is a case of interest.

USING an ELISA technique, concentrations of gamma-interferon and interleukin-2 were assayed in the supernatants of colonic intraepithelial lymphocytes cultured with or without phytohaemagglutinin (PHA). Intraepithelial lymphocytes produced low concentrations of gamma-interferon and interleukin-2 when stimulated with PHA, but significantly more than when unstimulated (p < 0.05). There was no difference in production of these cytokines by IEL from control or inflammatory bowel disease.