Possible roles of amyloids in malaria pathophysiology

The main therapeutic and prophylactic tools against malaria have been locked for more than a century in the classical approaches of using drugs targeting metabolic processes of the causing agent, the protist Plasmodium spp., and of designing vaccines against chosen antigens found on the parasite's surface. Given the extraordinary resources exhibited by Plasmodium to escape these traditional strategies, which have not been able to free humankind from the scourge of malaria despite much effort invested in them, new concepts have to be explored in order to advance toward eradication of the disease. In this context, amyloid-forming proteins and peptides found in the proteome of the pathogen should perhaps cease being regarded as mere anomalous molecules. Their likely functionality in the pathophysiology of Plasmodium calls for attention being paid to them as a possible Achilles' heel of malaria. Here we will give an overview of Plasmodium-encoded amyloid-forming polypeptides as potential therapeutic targets and toxic elements, particularly in relation to cerebral malaria and the blood-brain barrier function. We will also discuss the recent finding that the genome of the parasite contains an astonishingly high proportion of prionogenic domains

First Report of Babesia microti-Caused Babesiosis in Spain

Babesiosis is an emerging zoonosis now found in several areas of the world. Using PCR and indirect immunofluorescence assay, we have diagnosed the first case of human babesiosis caused by Babesia microti in Spain. Diagnosis was delayed because of the nonspecific clinical symptoms that occurred in an immunocompetent patient.We thank Cesar Eguiluz for his contribution to this study. This work is funded by the Surveillance Program of the Centro Nacional de Microbiología, the Center for Collaborative Research (RETIC-RICET), and the grants from Ministerio de Economia y Competitividad of Spain (grant numbers AGL2010-21774 and AGL2014-56193-R awarded to E.M. and L.M.G. and grant number BIO2013-44565-R awarded to J.M.B.) and the NIH of the USA (grant numbers HL105694 and HL129215 awarded to C.A.L.)

Plasmodium falciparum immunodominant IgG epitopes in subclinical malaria.

Incomplete non-sterile immunity to malaria is attained in endemic regions after recurrent infections by a large percentage of the adult population, who carry the malaria parasite asymptomatically. Although blood-stage Plasmodium falciparum rapidly elicits IgG responses, the target antigens of partially protective and non-protective IgG antibodies as well as the basis for the acquisition of these antibodies remain largely unknown. We performed IgG-immunomics to screen for P. falciparum antigens and to identify epitopes associated with exposure and clinical disease. Sera from malaria cases identified five prevalent antigens recognized by all analyzed patients' IgGs. Epitope mapping of them, using adult and children sera samples from an endemic malaria region in Ghana segregated into patients with positive or negative subclinical detection of P. falciparum, revealed binding specificity for two 20-mer immunodominant antigenic regions within the START-related lipid transfer protein and the protein disulfide isomerase PDI8. These 20-mer epitopes challenged with sera samples from children under 5 years old displayed specific IgG binding in those with detectable parasitemia, even at subclinical level. These results suggest that humoral response against START and PDI8 antigens may be triggered at submicroscopic parasitemia levels in children and may eventually be used to differentially diagnose subclinical malaria in children.This work was supported by Spanish-MINECO grants BIO2013-44565R and BIO2016-77430R and a research fellowship to P.A. from Universidad Complutense de Madrid.S

Differential immune response associated to malaria outcome is detectable in peripheral blood following Plasmodium yoelii infection in mice.

Malaria infection in humans elicits a wide range of immune responses that can be detected in peripheral blood, but we lack detailed long-term follow-up data on the primary and subsequent infections that lead to naturally acquired immunity. Studies on antimalarial immune responses in mice have been based on models yielding homogenous infection profiles. Here, we present a mouse model in which a heterogeneous course of Plasmodium yoelii lethal malaria infection is produced in a non-congenic ICR strain to allow comparison among different immunological and clinical outcomes. Three different disease courses were observed ranging from a fatal outcome, either early or late, to a self-resolved infection that conferred long-term immunity against re-infection. Qualitative and quantitative changes produced in leukocyte subpopulations and cytokine profiles detected in peripheral blood during the first week of infection revealed that monocytes, dendritic cells and immature B cells were the main cell subsets present in highly-parasitized mice dying in the first week after infection. Besides, CD4(+)CD25(high) T cells expanded at an earlier time point in early deceased mice than in surviving mice and expressed higher levels of intracellular Foxp3 protein. In contrast, survivors showed a limited increase of cytokines release and stable circulating innate cells. From the second week of infection, mice that would die or survive showed similar immune profiles, although CD4(+)CD25(high) T cells number increased earlier in mice with the worst prognosis. In surviving mice the expansion of activated circulating T cell and switched-class B cells with a long-term protective humoral response from the second infection week is remarkable. Our results demonstrate that the follow-up studies of immunological blood parameters during a malaria infection can offer information about the course of the pathological process and the immune response

First Report of Babesia microti

Babesiosis is an emerging zoonosis now found in several areas of the world. Using PCR and indirect immunofluorescence assay, we have diagnosed the first case of human babesiosis caused by Babesia microti in Spain. Diagnosis was delayed because of the nonspecific clinical symptoms that occurred in an immunocompetent patient

Impact of curative pelvic radiotherapy on the gut environment of prostate cancer patients

Trabajo presentado en el 10th Workshop on Probiotics and Prebiotics, de la Sociedad Española de Probióticos y Prebióticos (SEPyP), celebrado en Las Palmas de Gran Canarias, del 6 al 8 de febrero de 2019[Background] Gastrointestinal symptoms are frequent after pelvic radiotherapy and can greatly affect the quality of life of cancer survivors. The effect of radiation on the intestinal microbiome, and the implications of a radiotherapy-induced dysbiosis and the derived intestinal inflammation have received very little attention. [Aim] To perform a follow-up study in patients with prostate cancer for investigating alterations in gut microbiota and metabolites induced by pelvic radiotherapy and associations with inflammation and dietary changes. [Methods] Fourteen patients with prostate cancer undergoing pelvic radiotherapy were recruited and followed during the anti-cancer treatment until two months after finishing. Four stool samples were collected from each patient and changes in the bacterial communities were investigated by sequencing the V3-V4 region of the 16S rRNA gene with Illumina Technology (Miseq PE250), meanwhile short chain fatty acids (SCFAs) were analysed by gas chromatography. Additionally, calprotectin levels were determined using an ELISA kit and, evaluation of dietary intake was recorded by means of semi quantitative food frequency questionnaires. [Results] The composition of the gut communities changes along the radiation treatment, being the Bacteroidetes, the group more affected (p= 0.008, Wilcoxon test). Total SCFAs in feces was reduced with pelvic radiation. In particular, statistical differences were observed for butyrate and acetate excretion with respect to basal time. On the contrary, fecal calprotectin increased significantly during radiotherapy (p= 0.016). In addition, statistical differences in the energy intake were observed before and after two months of radiotherapy. Conclusions: An impact of pelvic radiotherapy on gut microbiota composition and metabolites was observed in prostate cancer patients. Intestinal inflammation occurs at the same time that the microbiome shifts. The effect of radiation was partially, but not completely, restored after two months of finishing the anti-cancer therapy, with changes in the food ingestion patterns still noticeable at this time point

Microscopic and submicroscopic infection by Plasmodium falciparum: Immunoglobulin M and A profiles as markers of intensity and exposure

Assessment of serological Plasmodium falciparum-specific antibodies in highly endemic areas provides valuable information about malaria status and parasite exposure in the population. Although serological evidence of Plasmodium exposure is commonly determined by Plasmodium-specific immunoglobulin G (IgG) levels; IgM and IgA are likely markers of malaria status that remain relatively unexplored. Previous studies on IgM and IgA responses have been based on their affinity for single antigens with shortage of immune responses analysis against the whole Plasmodium proteome. Here, we provide evidence of how P. falciparum infection triggers the production of specific IgM and IgA in plasma and its relationship with parasite density and changes in hematological parameters. A total of 201 individuals attending a hospital in Breman Asikuma, Ghana, were recruited into this study. Total and P. falciparum-specific IgM, IgA, and IgG were assessed by ELISA and examined in relation to age (0-5, 14-49, and ≥50 age ranges); infection (submicroscopic vs. microscopic malaria); pregnancy and hematological parameters. Well-known IgG response was used as baseline control. P. falciparum-specific IgM and IgA levels increased in the population with the age, similarly to IgG. These data confirm that acquired humoral immunity develops by repeated infections through the years endorsing IgM and IgA as exposure markers in endemic malaria regions. High levels of specific IgA and IgM in children were associated with microscopic malaria and worse prognosis, because most of them showed severe anemia. This new finding shows that IgM and IgA may be used as diagnostic markers in this age group. We also found an extremely high prevalence of submicroscopic malaria (46.27% on average) accompanied by IgM and IgA levels indistinguishable from those of uninfected individuals. These data, together with the observed lack of sensitivity of rapid diagnostic tests (RDTs) compared to PCR, invoke the urgent need to implement diagnostic markers for submicroscopic malaria. Overall, this study opens the potential use of P. falciparum-specific IgM and IgA as new serological markers to predict malaria status in children and parasite exposure in endemic populations. The difficulties in finding markers of submicroscopic malaria are highlighted, emphasizing the need to explore this field in depth.Spanish-MINECO (BIO2016-77430R)Univesida Complutense de Madrid (CT42/18-CT43/18)Comunidad de Madrid (/19-22460)Depto. de Bioquímica y Biología MolecularFac. de VeterinariaTRUEpu

Monocytes and DCs increase in blood of ED mice during acute infection.

<p>WBCs were isolated from the PB during the 1^st<i>PyL</i> infection in ICR mice and (<i>A</i>) monocytes (Mac3⁺ MHC II⁺) and DCs (CD11c⁺ MHC II⁺) were detected by flow cytometry. Animals were classified depending on the infection profiles as early deceased (ED), late deceased (LD) or surviving (S) and (<i>B, C</i>) their cell frequencies with respect to total leukocytes and numbers were recorded. Data express mean ± SEM of 2 independent experiments, each with n>3 mice per time point. The data for each infected mouse was normalized to the data recorded in 5 uninfected mice per experiment. Initial numbers of macrophages were 10.69±2.57×10⁴ and of DCs were 3.80±0.30×10⁵ per ml of blood.*<i>p</i><0.05 with respect to uninfected mice.</p

<i>P. yoelii</i> 17XL infection in ICR mice leads to three different infection profiles: early death (ED), late death (LD) or survival (S).

<p>*Significant differences between groups (<i>p</i><0.05), except group indicated.</p

Cytokine antibody array analysis.

<p>ICR mice infected with 2×10⁷<i>PyL</i> iRBCs were classified as early deceased (ED) mice or surviving (S) mice. Pooled sera from 4-5 mice in each group collected on days 3 and 7 pi were subjected to the RayBio Mouse Cytokine Array C2 and the density of dots on a membrane for each cytokine was measured and normalized to those obtained using positive Ab array controls.</p