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The observation that mice infected with mouse hepatitis virus (MHV) develop autoantibodies directed mainly to liver fumarylacetoacetate hydrolase (FAH) enabled the development of an ELISA applicable to the detection of MHV-infection. The method, based on the titration of antibodies to semipurified FAH from rat liver, is easy, economical, and does not require the isolation of viral proteins from large MHV stocks. Furthermore, since sera from mice immunized with a purified fraction of the rat liver enzyme do react with its homologous protein, this antiserum can be used as a positive control avoiding the manipulation of samples from MHV-infected animals. [Copyright &y& Elsevier]

Arginine kinase (AK) is an enzyme present in various invertebrates, as well as in some trypanosomatids such as T. cruzi , the etiological agent that causes Chagas disease. In invertebrates, this protein acts as an allergen inducing an IgE-type humoral immune response. Since AK is a highly conserved protein, we decided to study whether patients with chronic Chagas disease (CCD) produce specific antibodies against T. cruzi AK (Tc AK). Plasma from patients with CCD, with and without cardiac alterations and non-infected individuals were evaluated for the presence of anti- Tc AK IgG and IgE antibodies by ELISA, including detection of specific IgG subclasses. Our results showed that the levels of specific anti- Tc AK IgG and IgE were different between infected and non-infected individuals, but comparable between those with different clinical manifestations. Interestingly, anti- Tc AK IgG4 antibodies associated with IgE-mediated allergenic processes were also increased in CCD patients. Finally, we found that several of the predicted B cell epitopes in Tc AK matched allergenic peptides previously described for its homologues in other organisms. Our results revealed for the first time a parasite's specific IgE antibody target and suggest that Tc AK could contribute to delineate an inefficient B cell response by prompting a bias towards a Th2 profile. These findings also shed light on a potential allergenic response in the context of T. cruzi infection. [ABSTRACT FROM AUTHOR]

Abstract: In human environments subjected to natural hazards, places such as plazas, parks and free areas can, after a catastrophe, be places for refuge which can satisfy survival needs and support adaptation. The relationships of such an open space system and the urban form, are explored in this study by focussing on the spatial context of two Chilean cities affected by earthquakes. Data was collected in interviews with people from emergency organisations using the Projecting Mapping Technique, and subjected to Content and Geographic Information System analyses to identify the type, utility and distribution of the open space system for earthquake recovery. The objective was to evaluate, by means of different spatial indexes, the extent the open space system of these cities impact on measures associated with urban resilience, namely overlap in governance and diversity. Findings suggest that the regularity of the grid and city density affect the adaptive capacity of cities, hence, resilience. Findings also shed light on a methodological approach, including participatory and geographical data, through which these resilient aspects can be explored and evaluated in other human environments prone to earthquakes. [Copyright &y& Elsevier]

Abstract: High levels of antibodies (Abs) against the C-terminal end of the Trypanosoma cruzi ribosomal P2β protein, defined by the R13 peptide, are detected in sera from patients with chronic Chagas heart disease (cChHD). These Abs can cross-react with the β1-adrenergic receptor (β1-AR), inducing a functional response in cardiomyocytes. In this study, we report that a monoclonal Ab against the R13 peptide, called mAb 17.2, and its single-chain Fv fragment (scFv), C5, caused apoptosis of murine adult cardiac HL-1 cells, and this effect was inhibited by pre-incubation with the β-blocker, propranolol. In addition, apoptosis induced by mAb 17.2 might involve the mitochondrial pathway evidenced by an increase in pro-apoptotic molecule, Bax/anti-apoptotic molecule, BclXL, mRNA levels. HL-1 cells also underwent apoptosis after incubation with nine of 23 IgGs from cChHD patients (39.1%) that presented reactivity against R13 peptide and β1-AR. The apoptotic effect caused by these IgGs was partially abolished by pre-incubation with R13 peptide or propranolol, suggesting the involvement of the C-terminal end of ribosomal P proteins and the β-adrenergic pathway. Moreover, we observed high rates of cardiomyocyte apoptosis in two tissue samples from cChHD patients by using a TUNEL assay and staining of active caspase-3. Our data demonstrate that Abs developed during T. cruzi infection have a strong cardiomyocyte apoptosis inducing ability, which could contribute to the heart disease developed in patients with cChHD. [Copyright &y& Elsevier]