The intestinal expulsion of the roundworm Ascaris suum is associated with eosinophils, intra-epithelial T cells and decreased intestinal transit time

Ascaris lumbricoides remains the most common endoparasite in humans, yet there is still very little information available about the immunological principles of protection, especially those directed against larval stages. Due to the natural host-parasite relationship, pigs infected with A. suum make an excellent model to study the mechanisms of protection against this nematode. In pigs, a self-cure reaction eliminates most larvae from the small intestine between 14 and 21 days post infection. In this study, we investigated the mucosal immune response leading to the expulsion of A. suum and the contribution of the hepato-tracheal migration. Self-cure was independent of previous passage through the liver or lungs, as infection with lung stage larvae did not impair self-cure. When animals were infected with 14-day-old intestinal larvae, the larvae were being driven distally in the small intestine around 7 days post infection but by 18 days post infection they re-inhabited the proximal part of the small intestine, indicating that more developed larvae can counter the expulsion mechanism. Self-cure was consistently associated with eosinophilia and intra-epithelial T cells in the jejunum. Furthermore, we identified increased gut movement as a possible mechanism of self-cure as the small intestinal transit time was markedly decreased at the time of expulsion of the worms. Taken together, these results shed new light on the mechanisms of self-cure that occur during A. suum infections

Lung adenocarcinoma originates from retrovirus infection of proliferating type 2 pneumocytes during pulmonary post-natal development or tissue repair

Jaagsiekte sheep retrovirus (JSRV) is a unique oncogenic virus with distinctive biological properties. JSRV is the only virus causing a naturally occurring lung cancer (ovine pulmonary adenocarcinoma, OPA) and possessing a major structural protein that functions as a dominant oncoprotein. Lung cancer is the major cause of death among cancer patients. OPA can be an extremely useful animal model in order to identify the cells originating lung adenocarcinoma and to study the early events of pulmonary carcinogenesis. In this study, we demonstrated that lung adenocarcinoma in sheep originates from infection and transformation of proliferating type 2 pneumocytes (termed here lung alveolar proliferating cells, LAPCs). We excluded that OPA originates from a bronchioalveolar stem cell, or from mature post-mitotic type 2 pneumocytes or from either proliferating or non-proliferating Clara cells. We show that young animals possess abundant LAPCs and are highly susceptible to JSRV infection and transformation. On the contrary, healthy adult sheep, which are normally resistant to experimental OPA induction, exhibit a relatively low number of LAPCs and are resistant to JSRV infection of the respiratory epithelium. Importantly, induction of lung injury increased dramatically the number of LAPCs in adult sheep and rendered these animals fully susceptible to JSRV infection and transformation. Furthermore, we show that JSRV preferentially infects actively dividing cell in vitro. Overall, our study provides unique insights into pulmonary biology and carcinogenesis and suggests that JSRV and its host have reached an evolutionary equilibrium in which productive infection (and transformation) can occur only in cells that are scarce for most of the lifespan of the sheep. Our data also indicate that, at least in this model, inflammation can predispose to retroviral infection and cancer

Dried blood spots as a source of anti-malarial antibodies for epidemiological studies

BACKGROUND: Blood spots collected onto filter paper are an established and convenient source of antibodies for serological diagnosis and epidemiological surveys. Although recommendations for the storage and analysis of small molecule analytes in blood spots exist, there are no published systematic studies of the stability of antibodies under different storage conditions. METHODS: Blood spots, on filter paper or glass fibre mats and containing malaria-endemic plasma, were desiccated and stored at various temperatures for different times. Eluates of these spots were assayed for antibodies against two Plasmodium falciparum antigens, MSP-119 and MSP2, and calculated titres used to fit an exponential (first order kinetic) decay model. The first order rate constants (k) for each spot storage temperature were used to fit an Arrhenius equation, in order to estimate the thermal and temporal stability of antibodies in dried blood spots. The utility of blood spots for serological assays was confirmed by comparing antibodies eluted from blood spots with the equivalent plasma values in a series of samples from North Eastern Tanzania and by using blood spot-derived antibodies to estimate malaria transmission intensity in this site and for two localities in Uganda. RESULTS: Antibodies in spots on filter paper and glass fibre paper had similar stabilities but blood was more easily absorbed onto filter papers than glass fibre, spots were more regular and spot size was more closely correlated with blood volume for filter paper spots. Desiccated spots could be stored at or below 4 degrees C for extended periods, but were stable for only very limited periods at ambient temperature. When desiccated, recoveries of antibodies that are predominantly of IgG1 or IgG3 subclasses were similar. Recoveries of antibodies from paired samples of serum and of blood spots from Tanzania which had been suitably stored showed similar recoveries of antibodies, but spots which had been stored for extended periods at ambient humidity and temperature showed severe loss of recoveries. Estimates of malaria transmission intensity obtained from serum and from blood spots were similar, and values obtained using blood spots agreed well with entomologically determined values. CONCLUSION: This study has demonstrated the suitability of filter paper blood spots paper for collection of serum antibodies, and provided clear guidelines for the treatment and storage of filter papers which emphasize the importance of desiccation and minimisation of time spent at ambient temperatures. A recommended protocol for collecting, storing and assaying blood spots is provided

Population dynamics of an RNA virus and its defective interfering particles in passage cultures

<p>Abstract</p> <p>Background</p> <p>Viruses can fall prey to their defective interfering (DI) particles. When viruses are cultured by serial passage on susceptible host cells, the presence of virus-like DI particles can cause virus populations to rise and fall, reflecting predator-prey interactions between DI and virus particles. The levels of virus and DI particles in each population passage can be determined experimentally by plaque and yield-reduction assays, respectively.</p> <p>Results</p> <p>To better understand DI and virus particle interactions we measured vesicular stomatitis virus and DI particle production during serial-passage culture on BHK cells. When the multiplicity of infection (MOI, or ratio of infectious virus particles to cells) was fixed, virus yields followed a pattern of progressive decline, with higher MOI driving earlier and faster drops in virus level. These patterns of virus decline were consistent with predictions from a mathematical model based on single-passage behavior of cells co-infected with virus and DI particles. By contrast, the production of virus during fixed-volume passages exhibited irregular fluctuations that could not be described by either the steady-state or regular oscillatory dynamics of the model. However, these irregularities were, to a significant degree, reproduced when measured host-cell levels were incorporated into the model, revealing a high sensitivity of virus and DI particle populations to fluctuations in available cell resources.</p> <p>Conclusions</p> <p>This study shows how the development of mathematical models, when guided by quantitative experiments, can provide new insight into the dynamic behavior of virus populations.</p

Evaluation of Intereye Corneal Asymmetry in Patients with Keratoconus. A Scheimpflug Imaging Study

Purpose: To assess the correlation between keratoconus severity and intereye asymmetry of pachymetric data and posterior elevation values and to evaluate their combined accuracy in discriminating normal corneas from those with keratoconus. Methods: This study included 97 patients: 65 subjects with bilateral normal corneas (NC) and 32 with keratoconus (KC). Central corneal thickness (CCT), thinnest corneal thickness (ThCT) and posterior elevation (PE) at the thinnest point of the cornea were measured in both eyes using Scheimpflug imaging. Intereye asymmetry and its correlation with keratoconus severity were calculated for each variable. The area under the receiver operating characteristic curve (AUROC) was used to compare predictive accuracy of different variables for keratoconus. Results: In normal eyes, intereye differences were significantly lower compared with the keratoconus eyes (p<0.001, for CCT, ThCT and PE). There was a significant exponential correlation between disease severity and intereye asymmetry of steep keratometry (r(2) = 0.55, p<0.001), CCT (r(2) = 0.39, p<0.001), ThCT (r(2) = 0.48, p<0.001) and PE (r(2) = 0.64, p<0.001). After adjustment for keratoconus severity, asymmetry in thinnest pachymetry proved to be the best parameter to characterize intereye corneal asymmetry in keratoconus. This variable had high accuracy and significantly better discriminating ability (AUROC: 0.99) for KC than posterior elevation (AUROC: 0.96), ThCT (AUROC: 0.94) or CCT (AUROC: 0.92) alone. Conclusions: There is an increased intereye asymmetry in keratometry, pachymetry and posterior corneal elevation values in keratoconic patients compared to subjects with normal corneas. Keratoconus patients with more severe disease are also more asymmetric in their disease status which should be taken into account during clinical care

Crystallization of Ti33Cu67 metallic glass under high-current density electrical pulses

We have studied the phase and structure evolution of the Ti33Cu67 amorphous alloy subjected to electrical pulses of high current density. By varying the pulse parameters, different stages of crystallization could be observed in the samples. Partial polymorphic nanocrystallization resulting in the formation of 5- to 8-nm crystallites of the TiCu2 intermetallic in the residual amorphous matrix occurred when the maximum current density reached 9.7·108 A m-2 and the pulse duration was 140 μs, though the calculated temperature increase due to Joule heating was not enough to reach the crystallization temperature of the alloy. Samples subjected to higher current densities and higher values of the evolved Joule heat per unit mass fully crystallized and contained the Ti2Cu3 and TiCu3 phases. A common feature of the crystallized ribbons was their non-uniform microstructure with regions that experienced local melting and rapid solidification

The conservation and uniqueness of the caspase family in the basal chordate, amphioxus

<p>Abstract</p> <p>Background</p> <p>The caspase family, which plays a central role in apoptosis in metazoans, has undergone an expansion in amphioxus, increasing to 45 members through domain recombination and shuffling.</p> <p>Results</p> <p>In order to shed light on the conservation and uniqueness of this family in amphioxus, we cloned three representative caspase genes, designated as <it>bbtCaspase-8, bbtCaspase-1/2 </it>and <it>bbtCaspase3</it>-like, from the amphioxus <it>Branchiostoma belcheri tsingtauense</it>. We found that <it>bbtCaspase-8 </it>with conserved protein architecture is involved in the Fas-associated death domain-Caspase-8 mediated pro-apoptotic extrinsic pathway, while <it>bbtCaspase3</it>-like may mediate a nuclear apoptotic pathway in amphioxus. Also, <it>bbtCaspase-1/2 </it>can co-localize with <it>bbtFADD2 </it>in the nucleus, and be recruited to the cytoplasm by amphioxus apoptosis associated speck-like proteins containing a caspase recruitment domain, indicating that <it>bbtCaspase-1/2 </it>may serve as a switch between apoptosis and caspase-dependent innate immune response in invertebrates. Finally, amphioxus extrinsic apoptotic pathway related caspases played important roles in early embryogenesis.</p> <p>Conclusions</p> <p>Our study not only demonstrates the conservation of <it>bbtCaspase-8 </it>in apoptosis, but also reveals the unique features of several amphioxus caspases with novel domain architectures arose some 500 million years ago.</p

Autonomous Targeting of Infectious Superspreaders Using Engineered Transmissible Therapies

Infectious disease treatments, both pharmaceutical and vaccine, face three universal challenges: the difficulty of targeting treatments to high-risk ‘superspreader’ populations who drive the great majority of disease spread, behavioral barriers in the host population (such as poor compliance and risk disinhibition), and the evolution of pathogen resistance. Here, we describe a proposed intervention that would overcome these challenges by capitalizing upon Therapeutic Interfering Particles (TIPs) that are engineered to replicate conditionally in the presence of the pathogen and spread between individuals — analogous to ‘transmissible immunization’ that occurs with live-attenuated vaccines (but without the potential for reversion to virulence). Building on analyses of HIV field data from sub-Saharan Africa, we construct a multi-scale model, beginning at the single-cell level, to predict the effect of TIPs on individual patient viral loads and ultimately population-level disease prevalence. Our results show that a TIP, engineered with properties based on a recent HIV gene-therapy trial, could stably lower HIV/AIDS prevalence by ∼30-fold within 50 years and could complement current therapies. In contrast, optimistic antiretroviral therapy or vaccination campaigns alone could only lower HIV/AIDS prevalence by <2-fold over 50 years. The TIP's efficacy arises from its exploitation of the same risk factors as the pathogen, allowing it to autonomously penetrate superspreader populations, maintain efficacy despite behavioral disinhibition, and limit viral resistance. While demonstrated here for HIV, the TIP concept could apply broadly to many viral infectious diseases and would represent a new paradigm for disease control, away from pathogen eradication but toward robust disease suppression