Trypanosoma cruzi Virulence Factors for the Diagnosis of Chagas' Disease.

trans-Sialidase and cruzipain are important virulence factors from Trypanosoma cruzi, the etiological agent of Chagas disease, that have highly antigenic domains in their structure and were reported as potential tools for diagnosis of the illness. The aim of the present study is to assess the possibility of using cruzipain and the catalytic domain of trans-sialidase in a Surface Plasmon Resonance-based immunosensor for the diagnosis of chronic Chagas disease. Immunoassays carried out with canine sera verified that cruzipain allows the detection of anti-Trypanosoma cruzi antibodies whereas recombinant trans-sialidase did not yield specific detections, due to the high dilutions of serum used in the immunoassays that hinder the possibility to sense the specific low titer antibodies. The developed cruzipain-based biosensor, whose price per assay is comparable to a commercial enzyme-linked immunosorbent assay (ELISA), was successfully applied for the rapid quantification of specific antibodies against Trypanosoma cruzi in fresh human sera showing an excellent agreement with ELISA.

α-Haemolysin production, as a single factor, causes fulminant sepsis in a model of Escherichia coli-induced bacteraemia.

α-Haemolysin (HlyA) from uropathogenic Escherichia coli has been demonstrated to be a significant virulence factor for ascending urinary tract infections. Once the E. coli reach the well-vascularised kidneys, there is a high risk of bacteraemia and a subsequent septic host response. Despite this, HlyA has the potential to accelerate the host response both directly and via its ability to facilitate adenosine triphosphate release from cells. It has not been settled whether HlyA aggravates bacteraemia into a septic state. To address this, we used an E. coli strain in a model of acute urosepsis that was either transfected with a plasmid containing the full HlyA operon or one with deletion in the HlyA gene. Here, we show that HlyA accelerates the host response to E. coli in the circulation. Mice exposed to HlyA-producing E. coli showed massively increased proinflammatory cytokines, a substantial fall in circulating thrombocytes, extensive haematuria, and intravascular haemolysis. This was not seen in mice exposed to either E. coli that do not secrete HlyA or vehicle controls. Consistent with the massive host response to the bacteria, the mice exposed to HlyA-producing E. coli died exceedingly early, whereas mice exposed to E. coli without HlyA production and vehicle controls survived the entire observation period. These data allow us to conclude that HlyA is a virulence factor that accelerates a state of bacteraemia into fulminant sepsis in a mouse model.

Pyocyanin induces systemic oxidative stress, inflammation and behavioral changes in vivo.

Pyocyanin (PCN) is a virulence factor secreted by Pseudomonas aeruginosa (P. aeruginosa) that has been shown to have numerous toxic effects in both in vitro and in vivo studies. Such toxicities include pro-inflammatory and pro-oxidant mediated responses. It is hypothesized that PCN can cross biological membranes and reach the systemic circulation, but no previous studies have investigated this. The aim of this study was, therefore, to quantify PCN in plasma and assess if systemic responses were occurring after localized intranasal administration in C57BL/6 J mice. This was achieved through the plasma quantification of PCN and assessment of changes to behavior using two commonly used tests, the forced swimming test and the open field test. Furthermore, evidence of systemic oxidative stress and inflammation was measured using malondialdehyde (MDA) and TNF-α post PCN exposure. PCN was found to cross into systemic circulation but in a variable manner. Furthermore, significant increases in plasma TNF-α and MDA (both p < 0.001) were observed along with changes in behavior indicative of systemic inflammatory responses.

Validation of a Novel Immunoline Assay for Patient Stratification according to Virulence of the Infecting Helicobacter pylori Strain and Eradication Status.

Helicobacter pylori infection shows a worldwide prevalence of around 50%. However, only a minority of infected individuals develop clinical symptoms or diseases. The presence of H. pylori virulence factors, such as CagA and VacA, has been associated with disease development, but assessment of virulence factor presence requires gastric biopsies. Here, we evaluate the H. pylori recomLine test for risk stratification of infected patients by comparing the test score and immune recognition of type I or type II strains defined by the virulence factors CagA, VacA, GroEL, UreA, HcpC, and gGT with patient's disease status according to histology. Moreover, the immune responses of eradicated individuals from two different populations were analysed. Their immune response frequencies and intensities against all antigens except CagA declined below the detection limit. CagA was particularly long lasting in both independent populations. An isolated CagA band often represents past eradication with a likelihood of 88.7%. In addition, a high recomLine score was significantly associated with high-grade gastritis, atrophy, intestinal metaplasia, and gastric cancer. Thus, the recomLine is a sensitive and specific noninvasive test for detecting serum responses against H. pylori in actively infected and eradicated individuals. Moreover, it allows stratifying patients according to their disease state.

Elevated Levels of Interferon-γ Are Associated with High Levels of Epstein-Barr Virus Reactivation in Patients with the Intestinal Type of Gastric Cancer.

BACKGROUND: The inflammatory response directed against Helicobacter pylori (HP) is believed to be one of the main triggers of the appearance of gastric lesions and their progression to gastric cancer (GC). Epstein-Barr virus (EBV) has been found responsible for about 10% of all GCs, but the inflammatory response has not been studied in GC patients with evidence of high levels of EBV reactivation. OBJECTIVE: To determine the relationship between inflammation and antibodies against EBV reactivation antigens, HP, and the bacterium virulence factor CagA in patients with GC. METHODS: 127 GC patients, 46 gastritis patients, and 197 healthy subjects were studied. IL-1ß, IL-6, IL-8, IL-10, TNF-α, TGF-ß, MCP-1, and IFN-γ levels were measured in serum or plasma and compared against the antibody titers of VCA-IgG, HP, and the HP virulence factor CagA. Statistical associations were estimated. RESULTS: Significant ORs and positive trends were found between VCA-IgG and IFN-γ, specifically for patients with GC of intestinal type (OR: 6.4, 95% C.I. 1.2-35.4) (p < 0.044). CONCLUSIONS: We confirmed a positive association between a marker of EBV reactivation and intestinal gastric cancer and present evidence of a correlation with elevated serum levels of IFN-γ, but not with the other cytokines.

Protection of the Furin Cleavage Site in Low-Toxicity Immunotoxins Based on Pseudomonas Exotoxin A.

Recombinant immunotoxins (RITs) are fusions of an Fv-based targeting moiety and a toxin. Pseudomonas exotoxin A (PE) has been used to make several immunotoxins that have been evaluated in clinical trials. Immunogenicity of the bacterial toxin and off-target toxicity have limited the efficacy of these immunotoxins. To address these issues, we have previously made RITs in which the Fv is connected to domain III (PE24) by a furin cleavage site (FCS), thereby removing unneeded sequences of domain II. However, the PE24 containing RITs do not contain the naturally occurring disulfide bond around the furin cleavage sequence, because it was removed when domain II was deleted. This could potentially allow PE24 containing immunotoxins to be cleaved and inactivated before internalization by cell surface furin or other proteases in the blood stream or tumor microenvironment. Here, we describe five new RITs in which a disulfide bond is engineered to protect the FCS. The most active of these, SS1-Fab-DS3-PE24, shows a longer serum half-life than an RIT without the disulfide bond and has the same anti-tumor activity, despite being less cytotoxic in vitro. These results have significance for the production of de-immunized, low toxicity, PE24-based immunotoxins with a longer serum half-life.

Identification of Borrelia burgdorferi ospC genotypes in canine tissue following tick infestation: implications for Lyme disease vaccine and diagnostic assay design.

In endemic regions, Lyme disease is a potential health threat to dogs. Canine Lyme disease manifests with arthritis-induced lameness, anorexia, fever, lethargy, lymphadenopathy and, in some cases, fatal glomerulonephritis. A recent study revealed that the regional mean for the percentage of seropositive dogs in the north-east of the USA is 11.6%. The outer surface protein C (OspC) of Lyme disease spirochetes is an important virulence factor required for the establishment of infection in mammals. It is a leading candidate in human and canine Lyme disease vaccine development efforts. Over 30 distinct ospC phyletic types have been defined. It has been hypothesized that ospC genotype may influence mammalian host range. In this study, Ixodes scapularis ticks collected from the field in Rhode Island were assessed for infection with B. burgdorferi. Ticks were fed on purpose bred beagles to repletion and infection of the dogs was assessed through serology and PCR. Tissue biopsies (n=2) were collected from each dog 49 days post-tick infestation (dpi) and the ospC genotype of the infecting strains determined by direct PCR of DNA extracted from tissue or by PCR after cultivation of spirochetes from biopsy samples. The dominant ospC types associated with B. burgdorferi canine infections differed from those associated with human infection, indicating a relationship between ospC sequence and preferred host range. Knowledge of the most common ospC genotypes associated specifically with infection of dogs will facilitate the rational design of OspC-based canine Lyme disease vaccines and diagnostic assays.

The role of serum Pseudomonas aeruginosa antibodies in the diagnosis and follow-up of cystic fibrosis.

In cystic fibrosis (CF), if Pseudomonas aeruginosa (Pa) infection is not diagnosed and treated early, chronic colonization occurs, which causes rapid decline in pulmonary functions. The aim of this study was to evaluate Pa antibodies, compare them with Pa cultures and determine their role in early diagnosis and follow-up. Ninety CF patients were included; they were divided into chronic, intermittent, negative, and mucoid groups. They were evaluated every 3-6 months. In each visit, pulmonary function tests and sputum cultures were obtained, and Pa antibodies exotoxin A (ExoA), elastase (ELA) and alkaline protease (AP) were determined in the serum by enzyme-linked immunosorbent assay (ELISA). The most specific test that discriminated chronic colonized patients from noncolonized patients was Pa culture, and the presence of at least one antibody had the highest sensitivity. AP had the highest specificity, and ELA had the highest sensitivity. All antibodies were highest in the mucoid group. ELA was highest in chronic and lowest in the negative group. The presence of antibodies was much higher than positive Pa cultures in patients younger than five years of age. A negative correlation between forced expiratory volume in 1 second (FEV1) and AP was determined only in the mucoid group. In the two-year follow-up, antibody presence did not show a regular pattern. In CF, Pa antibodies can be early markers for diagnosis, especially in young children who cannot expectorate, but they should only be used together with sputum cultures for long-term follow-up and treatment.

Virus herpes humano 8: detección en células mononucleares de sangre periférica de pacientes con la infección por el virus de inmunodeficiencia humana: con/sin sarcoma de kaposi / Human herpes virus 8: detection in peripheral blood mononuclear cells from patients with human immunodeficiency virus infection with/without kaposi sarcoma

El ácido nucleico proveniente del virus herpes humano 8 esta presente en las células mononucleares de sangre periférica de un 50% a 90% de los pacientes con sarcoma de Kaposi, y 7% a 10% de los pacientes con la infección por el virus de inmunodeficiencia humana sin sarcoma de Kaposi. Nosotros estudiamos la prevalencia del virus herpes humano 8 en células mononucleares de sangre periférica provenientes de pacientes con la infección por el virus inmunodeficiencia humana con/sin sarcoma de Kaposi. Setenta y seis pacientes con la infección por el virus de inmunodeficiencia humana sin sarcoma de Kaposi y 15 pacientes con sarcoma de Kaposi asociado a la infección por el virus de inmunodeficiencia humana se incluyeron en el estudio. El ácido desoxirribonucleico se extrajo utilizando el método de fenol/cloroformo. El ácido desoxirribonucleico fue amplificado a través de la reacción en cadena de la polimerasa utilizando las sondas KS1 y KS2 específicas para el ORF26 del virus herpes humano 8. Las reacciones se consideraron positivas sólo si los productos de la región esperada de 233 pares de bases. Ninguno de los pacientes con la infección por el virus de inmunodeficiencia humana mostró la presencia de virus herpes humano 8 en las células mononucleares de sangre periférica, y después de un seguimiento de 2 años, ninguno ha desarrollado sarcoma de Kaposi. El virus herpes humano 8 se detectó en las células mononucleares de sangre periférica del 20% de los pacientes con sarcoma de Kaposi. Todos los pacientes pertenecían al grupo de "altó riesgo", y eran varones homosexuales. Ninguno recibió transfusiones sanguíneas. Estos datos preliminares sugieren que la prevalencia del virus herpes humano 8 en las células mononucleares de sangre periférica de los pacientes con la infección por el virus de inmunodeficiencia humana con/sin sarcoma de Kaposi es probablemente baja en comparación con pacientes provenientes de Estados Unidos y Europa

The nucleic acid of human herpes virus 8 is present in the peripheral blood mononuclear cells of between 50% and 90% of Kaposi sarcoma patients, 7% and 10% of human immunodeficiency virus infected patients without Kaposi sarcoma. We studied the prevalence of human herpes virus 8 in peripheral blood mononuclear cells from patients with human immunodeficiency virus infection with/without Koposi sarcoma. Seventy-six patients with human immunodeficiency virus infection without Kaposi sarcoma associated with human immunodeficiency virus infection were included. Desoxibonucleico acid was extracted from the sample by a standard phenol/chloroform extraction procedure. Desoxirribonucleico acid was polimerase chain reaction amplified using Kaposi sarcoma 1 and Kaposi sarcoma 2 primers specific for the human herpes virus 8 ORF26. Polimerase chain reaction were considered positive only if the polimerase chain reaction products hybridized in the expected 233 by region. None of human immunodeficiency virus infected patients showed the presence of human herpes virus 8 in the peripheral blood mononuclear cells, and after a follow-up of 2 years, none has developed Kaposi sarcoma. Human herpes virus 8 was detected in the peripheral blood mononuclear cells from 20% of patients with Kaposi sarcoma. All patients belonged to a "high risk group", were male and homosexuals. None received blood transfusion. These preliminary data suggest that the prevalence of human herpes virus 8 in peripheral blood mononuclear cells from human immunodeficiency virus infected patients with/withoul Kaposi sarcoma is probably low in comparison with patients from EE.UU and Europe

Hepatitis B viral factors and clinical outcomes of chronic hepatitis B.

Hepatitis B virus (HBV) infection is an important health problem and the major cause of chronic hepatitis, cirrhosis as well as hepatocellular carcinoma (HCC) worldwide. The natural history of chronic HBV infection can be divided into 4 dynamic phases in HBV carriers who acquire the virus early in life. In general, the frequency and severity of hepatitis flares in the immune clearance or reactivation phase predict disease progression in HBV carriers, and early HBeAg seroconversion typically confers a favorable outcome. In contrast, late or absent HBeAg seroconversion after multiple hepatitis flares accelerates the progression of chronic hepatitis to cirrhosis. Recently, several hepatitis B viral factors predictive of clinical outcomes have been identified. For example, serum HBV DNA level at enrollment is the best predictor of adverse outcomes (cirrhosis, HCC and death from liver disease) in adults with chronic HBV infection. In addition, HBV genotype C, basal core promoter (BCP) mutant and pre-S deletion mutant are associated with increased risk of HCC development. In conclusion, hepatitis B viral factors such as serum HBV DNA level, genotype and mutants have already been clarified to influence disease progression of chronic hepatitis B. Further studies are needed to investigate the pathogenic mechanism of each viral factor.

In vitro and in vivo cytotoxic activities of recombinant immunotoxin 8H9(Fv)-PE38 against breast cancer, osteosarcoma, and neuroblastoma.

The 8H9 monoclonal antibody (MAb) is highly reactive with a cell surface glycoprotein expressed on human breast cancers, childhood sarcomas, and neuroblastomas but is not reactive with the cell surface of normal human tissues. This specific reactivity suggests that MAb 8H9 may be useful for targeted cancer therapy. To explore this possibility, we generated two recombinant immunotoxins (ITs) using the single-chain Fv (scFv) of MAb 8H9. Initially the 8H9(scFv) cDNA was fused to a DNA encoding a 38-kDa truncated form of Pseudomonas exotoxin (PE38) to generate the IT 8H9(scFv)-PE38. The fusion gene was expressed in Escherichia coli, and the IT was purified to near homogeneity from inclusion bodies. The purified IT showed specific cytotoxicity on nine different cancer cell lines derived from breast cancer, osteosarcoma, and neuroblastomas, known to react with MAb 8H9. The cytotoxic activity was inhibited by MAb 8H9, showing the cytotoxic activity is specific. The antitumor activity of 8H9(scFv)-PE38 was evaluated in severe combined immunodeficient mice bearing MCF-7 breast cancers or OHS-M1 osteosarcomas. The IT showed a specific dose-dependent antitumor activity at 0.075 and 0.15 mg/kg. Next, a more stable disulfide-linked IT, 8H9(dsFv)-PE38, was constructed. It was produced in high yield (16%) and showed cytotoxic and antitumor activities similar to those of 8H9(scFv)-PE38. 8H9(dsFv)-PE38 was given to two cynomolgus monkeys at doses of 0.1 and 0.2 mg/kg i.v. QOD x 3 and was well tolerated. This shows that a dose that causes significant tumor regressions in mice is well tolerated by monkeys. These results make 8H9(dsFv)-PE38 a candidate for further development as a therapeutic agent for breast cancers, osteosarcomas, and neuroblastomas.