Immunoglobulin GM 3 23 5,13,14 phenotype is strongly associated with IgG1 antibody responses to Plasmodium vivax vaccine candidate antigens PvMSP1-19 and PvAMA-1

<p>Abstract</p> <p>Background</p> <p>Humoral immune responses play a key role in the development of immunity to malaria, but the host genetic factors that contribute to the naturally occurring immune responses to malarial antigens are not completely understood. The aim of the present investigation was to determine whether, in subjects exposed to malaria, GM and KM allotypes--genetic markers of immunoglobulin γ and κ-type light chains, respectively--contribute to the magnitude of natural antibody responses to target antigens that are leading vaccine candidates for protection against <it>Plasmodium vivax</it>.</p> <p>Methods</p> <p>Sera from 210 adults, who had been exposed to malaria transmission in the Brazilian Amazon endemic area, were allotyped for several GM and KM determinants by a standard hemagglutination-inhibition method. IgG subclass antibodies to <it>P. vivax </it>apical membrane antigen 1 (PvAMA-1) and merozoite surface protein 1 (PvMSP1-19) were determined by an enzyme-linked immunosorbent assay. Multiple linear regression models and the non-parametric Mann-Whitney test were used for data analyses.</p> <p>Results</p> <p>IgG1 antibody levels to both PvMSP1-19 and PvAMA-1 antigens were significantly higher (<it>P </it>= 0.004, <it>P </it>= 0.002, respectively) in subjects with the GM 3 23 5,13,14 phenotype than in those who lacked this phenotype.</p> <p>Conclusions</p> <p>Results presented here show that immunoglobulin GM allotypes contribute to the natural antibody responses to <it>P. vivax </it>malaria antigens. These findings have important implications for the effectiveness of vaccines containing PvAMA-1 or PvMSP1-19 antigens. They also shed light on the possible role of malaria as one of the evolutionary selective forces that may have contributed to the maintenance of the extensive polymorphism at the GM loci.</p

Growth Response of Drought-Stressed Pinus sylvestris Seedlings to Single- and Multi-Species Inoculation with Ectomycorrhizal Fungi

Many trees species form symbiotic associations with ectomycorrhizal (ECM) fungi, which improve nutrient and water acquisition of their host. Until now it is unclear whether the species richness of ECM fungi is beneficial for tree seedling performance, be it during moist conditions or drought. We performed a pot experiment using Pinus sylvestris seedlings inoculated with four selected ECM fungi (Cenococcum geophilum, Paxillus involutus, Rhizopogon roseolus and Suillus granulatus) to investigate (i) whether these four ECM fungi, in monoculture or in species mixtures, affect growth of P. sylvestris seedlings, and (ii) whether this effect can be attributed to species number per se or to species identity. Two different watering regimes (moist vs. dry) were applied to examine the context-dependency of the results. Additionally, we assessed the activity of eight extracellular enzymes in the root tips. Shoot growth was enhanced in the presence of S. granulatus, but not by any other ECM fungal species. The positive effect of S. granulatus on shoot growth was more pronounced under moist (threefold increase) than under dry conditions (twofold increase), indicating that the investigated ECM fungi did not provide additional support during drought stress. The activity of secreted extracellular enzymes was higher in S. granulatus than in any other species. In conclusion, our findings suggest that ECM fungal species composition may affect seedling performance in terms of aboveground biomass

Leucosis enzoótica bovina en Uruguay: ¿Hacia dónde vamos?

RESUMEN: En este trabajo se proponen medidas de control de la leucosis bovina en el Uruguay mediante 4 etapas: 1) interrumpir la trayectoria ascendente de la prevalencia de la enfermedad; 2) aplicar medidas inmediatas de control para disminuir rápidamente su prevalencia; 3) iniciar planes de eliminación de la enfermedad en aquellos establecimientos que hayan conseguido disminuir la prevalencia y 4) estimar el costo-beneficio del control o eliminación de la enfermedad en los establecimientos. ABSTRACT: In this paper, measures to control bovine leukosis in Uruguay are proposed through 4 stages: 1) interrupting the ascending trajectory of the prevalence of the disease; 2) apply immediate control measures to rapidly decrease its prevalence; 3) initiate plans to eliminatethe disease in those farms that have managed to reduce the prevalence; and 4) estimate the cost-benefit of controlling or eliminating the disease in the farms

Tree species rather than type of mycorrhizal association drives inorganic and organic nitrogen acquisition in tree-tree interactions.

Mycorrhizal fungi play an important role for the nitrogen (N) supply of trees. The influence of different mycorrhizal types on N acquisition in tree-tree interactions is, however, not well understood, particularly with regard to the competition for growth-limiting N. We studied the effect of competition between temperate forest tree species on their inorganic and organic N acquisition in relation to their mycorrhizal type (i.e., arbuscular mycorrhiza or ectomycorrhiza). In a field experiment, we quantified net N uptake capacity from inorganic and organic N sources using 15N/13C stable isotopes for arbuscular mycorrhizal tree species (i.e., Acer pseudoplatanus L., Fraxinus excelsior L., and Prunus avium L.) as well as ectomycorrhizal tree species (i.e., Carpinus betulus L., Fagus sylvatica L., and Tilia platyphyllos Scop.). All species were grown in intra- and interspecific competition (i.e., monoculture or mixture). Our results showed that N sources were not used complementarily depending on a species´ mycorrhizal association, but their uptake rather depended on the competitor indicating species-specific effects. Generally, ammonium was preferred over glutamine and glutamine over nitrate. In conclusion, our findings suggest that inorganic and organic N acquisition of the studied temperate tree species is less regulated by mycorrhizal association, but rather by the availability of specific N sources in the soil as well as the competitive environment of different tree species

Structural and affinity studies of IgM polyreactive natural autoantibodies.

International audienceNatural polyreactive autoantibodies (NAA) are an important component of the normal B cell repertoire. One intriguing characteristic of these Abs is their binding to various dissimilar Ags. It has been generally assumed that these Abs bind the Ags with low affinity, and are encoded by germline genes. We have used surface plasmon resonance to determine binding of avidities, and conducted a structural analysis of five murine monoclonal natural autoantibodies displaying a typical polyreactive binding pattern against cytoskeleton Ags and DNA. We show that 1) all the five Abs bind the different Ags with kinetic constants similar to those observed for immune Abs; 2) they express a restricted set of V(H) and V(L) genes, since the same V(H) gene is expressed by three out of the five, and one particular Vkappa gene was expressed twice. In addition, a single D gene segment was used by three of the five Abs; and 3) they express, in most cases, genes in a close germline configuration. Our amino acid sequence and modeling studies show that the distribution of exposed side chains in the NAA paratopes is close to the general pattern observed in the complementarity-determining regions (CDRs) of variable domains from immune Abs. Although CDR3 regions of the heavy chain have been postulated to play a major role in determining polyreactivity on the basis of recombinatorial experiments, our results failed to show any distinctive particularity of this region in terms of length or charge when compared with classical immune Abs

Conformational plasticity of a native retroviral capsid revealed by x-ray crystallography

International audienceRetroviruses depend on self-assembly of their capsid proteins (core particle) to yield infectious mature virions. Despite the essential role of the retroviral core, its high polymorphism has hindered high-resolution structural analyses. Here, we report the x-ray structure of the native capsid (CA) protein from bovine leukemia virus. CA is organized as hexamers that deviate substantially from sixfold symmetry, yet adjust to make two-dimensional pseudohexagonal arrays that mimic mature retroviral cores. Intra- and interhexameric quasi-equivalent contacts are uncovered, with flexible trimeric lateral contacts among hexamers, yet preserving very similar dimeric interfaces making the lattice. The conformation of each capsid subunit in the hexamer is therefore dictated by long-range interactions, revealing how the hexamers can also assemble into closed core particles, a relevant feature of retrovirus biology