Reovirus serotypes elicit distinctive patterns of recall immunity in humans

Mammalian orthoreoviruses (reoviruses) are ubiquitous viral agents that infect cells in respiratory and enteric tracts. The frequency and nature of human cellular immunoregulatory responses against reovirus are unknown. Here we establish systems to detect and quantify reovirus-induced cytokine and chemokine recall responses using primary cultures of virus-infected peripheral blood mononuclear cells (PBMC) and two widely used reovirus serotypes, type 1 Lang (T1L) and type 3 Dearing (T3D) reexposure in vitro. In cultures from 44 healthy adults, reovirus induced exceptionally strong CD4 and CD8 T-cell-dependent gamma interferon (IFN-γ) recall responses concomitant with intense interleukin 10 (IL-10) production. These responses were elicited independently of viral replication. Surprisingly, paired analyses of subject responses to these two common serotypes revealed that while both elicit intense Th1-dominated immunity, median T3D-driven responses were 2.2-fold weaker (P = 0.0004) than those elicited by T1L. Recall responses evoked by these viral serotypes differed markedly in their mechanism of regulation. T3D IL-10 and IFN-γ responses were CD4 and CD8 dependent and blocked by interfering with CD86 costimulation but were CD80 independent. T1L responses were consistently CD28 and CD80/86 independent. Thus, despite extensive genetic and morphological similarities between reovirus serotypes, the nature and intensity of the human recall responses as well as the control mechanisms regulating them are clearly distinct.     

Assessment of a bedside test for N-terminal pro B-type natriuretic peptide (NT-proBNP) to differentiate cardiac from non-cardiac causes of pleural effusion in cats

Background

Cats with pleural effusion represent common emergencies in small animal practice. The aim of this prospective study was to investigate the diagnostic ability of a point-of-care ELISA (POC-ELISA) for the measurement of N-terminal pro B-type natriuretic peptide (NT-proBNP) to differentiate cardiac from non-cardiac disease in cats with pleural effusion. The sample material for use of this rapid test was either plasma or diluted pleural effusion.Twenty cats with moderate to severe pleural effusion were prospectively recruited. The cats were grouped into two groups, with or without congestive heart failure (CHF; N-CHF), after complete work-up. Blood and effusion were collected in EDTA tubes. Plasma and pleural effusion supernatants were transferred into stabilizer tubes and frozen. POC-ELISA for NT-proBNP was performed with plasma and diluted effusion (1:1). Quantitative NT-proBNP measurement was performed in plasma and diluted and undiluted effusions.

Results

Six cats were assigned to the CHF group. Of the 14 cats in the N-CHF group, 6 had concurrent cardiac abnormalities that were not responsible for the effusion. For the detection of CHF, the test displayed respective sensitivities and specificities of 100% and 79% in plasma and 100% and 86% in diluted pleural fluid. Receiver operating characteristic (ROC) analysis for quantitative NT-proBNP measurement of plasma and diluted and undiluted pleural effusions displayed areas under the curve of 0.98, sensitivities of 100% and specificities of 86%. The optimum cut-off was calculated at 399 pmol/l in plasma and 229 pmol/l in the diluted effusion and 467 pmol/l in the undiluted effusion.

Conclusions

POC-ELISA for NT-proBNP in both plasma and diluted pleural effusion was suitable to differentiate cardiac from non-cardiac causes of feline pleural effusion. According to our results, use of pleural effusion is feasible, but dilution of the effusion before measurement seems to improve specificity.

     

Cooperating elephants mitigate competition until the stakes get too high

Cooperation is ubiquitous in the animal kingdom as it aims to maximize benefits through joint action. Selection, however, may also favor competitive behaviors that could violate cooperation. How animals mitigate competition is hotly debated, with particular interest in primates and little attention paid thus far to nonprimates. Using a loose-string pulling apparatus, we explored cooperative and competitive behavior, as well as mitigation of the latter, in semi-wild Asian elephants (Elephas maximus). Our results showed that elephants first maintained a very high cooperation rate (average = 80.8% across 45 sessions). Elephants applied “block,” “fight back,” “leave,” “move side,” and “submission” as mitigation strategies and adjusted these strategies according to their affiliation and rank difference with competition initiators. They usually applied a “fight back” mitigation strategy as a sanction when competition initiators were low ranking or when they had a close affiliation, but were submissive if the initiators were high ranking or when they were not closely affiliated. However, when the food reward was limited, the costly competitive behaviors (“monopoly” and “fight”) increased significantly, leading to a rapid breakdown in cooperation. The instability of elephant cooperation as a result of benefit reduction mirrors that of human society, suggesting that similar fundamental principles may underlie the evolution of cooperation across species.

This study shows that in a task requiring coordinated pulling, elephants compete for access to food but work to mitigate competition in order to maintain cooperation. If the cost of competition becomes too high, however, cooperation breaks down entirely. This behavior mirrors that seen in humans and other great apes, suggesting that certain cooperative mechanisms are not unique to primates.     

PopART-IBM,a highly efficient stochastic individual-based simulation model of generalised HIV epidemics developed in the context of the HPTN 071 (PopART) trial

Mathematical models are powerful tools in HIV epidemiology, producing quantitative projections of key indicators such as HIV incidence and prevalence. In order to improve the accuracy of predictions, such models need to incorporate a number of behavioural and biological heterogeneities, especially those related to the sexual network within which HIV transmission occurs. An individual-based model, which explicitly models sexual partnerships, is thus often the most natural type of model to choose. In this paper we present PopART-IBM, a computationally efficient individual-based model capable of simulating 50 years of an HIV epidemic in a large, high-prevalence community in under a minute. We show how the model calibrates within a Bayesian inference framework to detailed age- and sex-stratified data from multiple sources on HIV prevalence, awareness of HIV status, ART status, and viral suppression for an HPTN 071 (PopART) study community in Zambia, and present future projections of HIV prevalence and incidence for this community in the absence of trial intervention.     

Chronic development of collagen-induced arthritis is associated with arthritogenic antibodies against specific epitopes on type II collagen

Antibodies against type II collagen (CII) are important in the development of collagen-induced arthritis (CIA) and possibly also in rheumatoid arthritis. We have determined the fine specificity and arthritogenicity of the antibody response to CII in chronic relapsing variants of CIA. Immunization with rat CII in B10.Q or B10.Q(BALB/c×B10.Q)F₂ mice induces a chronic relapsing CIA. The antibody response to CII was determined by using triple-helical peptides of the major B cell epitopes. Each individual mouse had a unique epitope-specific response and this epitope predominance shifted distinctly during the course of the disease. In the B10.Q mice the antibodies specific for C1 and U1, and in the B10.Q(BALB/c×B10.Q)F₂ mice the antibodies specific for C1, U1 and J1, correlated with the development of chronic arthritis. Injection of monoclonal antibodies against these epitopes induced relapses in chronic arthritic mice. The development of chronic relapsing arthritis, initially induced by CII immunization, is associated with an arthritogenic antibody response to certain CII epitopes.     

Xylanases and carboxymethylcellulases of the rumen protozoa Polyplastron multivesiculatum, Eudiplodinium maggii and Entodinium sp

Endoglucanase and xylanase activities of three rumen protozoa, Polyplastron multivesiculatum, Eudiplodinium maggii, and Entodinium sp. were compared qualitatively by zymograms and quantitatively by measuring specific activities against different polysaccharides. A set of carboxymethylcellulases and xylanases was produced by the large ciliates whereas no band of activity was observed for Entodinium sp. in zymograms. Specific activity of endoglucanases from P. multivesiculatum (1.3 micromol mg prot(-1) min(-1)) was twice that of E. maggii, whereas xylanase specific activity (4.5 micromol mg prot(-1) min(-1)) was only half. Very weak activities were observed for Entodinium sp. A new xylanase gene, xyn11D, from P. multivesiculatum was reported and its gene product compared to 33 other family 11 xylanases. Phylogenetic analysis showed that xylanase sequences from rumen protozoa are closely related to those of bacteria.     

Arabidopsis AtCUL3a and AtCUL3b form complexes with members of the BTB/POZ-MATH protein family

The ubiquitin proteasome pathway in plants has been shown to be important for many developmental processes. The E3 ubiquitin-protein ligases facilitate transfer of the ubiquitin moiety to substrate proteins. Many E3 ligases contain cullin proteins as core subunits. Here, we show that Arabidopsis (Arabidopsis thaliana) AtCUL3 proteins interact in yeast two-hybrid and in vitro pull-down assays with proteins containing a BTB/POZ (broad complex, tramtrack, bric-a-brac/pox virus and zinc finger) motif. By changing specific amino acid residues within the proteins, critical parts of the cullin and BTB/POZ proteins are defined that are required for these kinds of interactions. In addition, we show that AtCUL3 proteins assemble with the RING-finger protein AtRBX1 and are targets for the RUB-conjugation pathway. The analysis of AtCUL3a and AtCUL3b expression as well as several BTB/POZ-MATH genes indicates that these genes are expressed in all parts of the plant. The results presented here provide strong evidence that AtCUL3a and AtCUL3b can assemble in Arabidopsis with BTB/POZ-MATH and AtRBX1 proteins to form functional E3 ligases.     

In vitro aromatic bioactivation of the weak estrogen E(2)alpha and genesis of DNA adducts

Specific A-ring hydroxylated metabolites of 17beta-estrogens are known to be endogenous pro-carcinogens, more particularly the 4-hydroxylated forms of estrogens produced by cytochrome P4501B1. In this study, we investigated whether estradiol-17alpha, the main hepatic residue of estradiol-17beta in cattle treated for anabolic purposes with estradiol containing implants, could be significantly metabolized by human cells, and whether its aromatic metabolites could induce the formation of DNA adducts as estradiol-17beta and estrone do. First, using a human kidney adenocarcinoma cell line, which expresses specifically the cytochrome P4501B1, we showed that estradiol-17alpha is bioactivated into a mixture of 2- and 4-catechol estrogens leading to the corresponding methoxyestrogens unambiguously identified by LC-APCI-MS/MS. We then demonstrated that the 2- and 4-hydroxylated derivatives of estradiol-17alpha incubated under oxidative conditions with calf thymus DNA gave stable DNA adducts and abasic sites, respectively. From these results, we can consider that human cells expressing CYP1B1-dependent hydroxylation activities metabolize estradiol-17alpha at the same magnitude as estradiol-17beta and estrone, and that in oxidative conditions, the resulting aromatic metabolites can lead to the formation of both stable and unstable DNA adducts.