The present work establishes for the first time the potential of mixed formulations of conventional and pegylated liposomes as a drug delivery strategy for improved treatment of VL.

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BackgroundIn past years, many researchers have sought canine visceral leishmaniasis (CVL) prevention through the characterization of Leishmania antigens as vaccine candidates. Despite these efforts, there is still no efficient vaccine for CVL control.MethodsIn the present study, we performed a pre-clinical vaccine trial using BALB/c mice to compare the effects of the multicomponent LBSap vaccine with those of Leish-Tec® and Leishmune®. Blood was collected to determine the frequency of peripheral blood cells and to evaluate hematologic and immunophenotypic parameters. Liver and spleen samples were collected for parasitological quantification, and spleen samples were used to access the cytokine profile.ResultsWhen measuring total IgG and IgG1 anti-Leishmania levels after the third vaccination and L. infantum challenge, it was evident that all vaccines were able to induce humoral immune response. Regarding the innate immune response, increased levels of NK CD3-CD49+ cells were the hallmark of all vaccinated groups, whereas only the Leish-Tec® group displayed a high frequency of CD14+ monocytes after L. infantum challenge. Moreover, CD3+CD4+ T cells were the main circulating lymphocytes induced after L. infantum challenge with all evaluated vaccines. Importantly, after L. infantum challenge, splenocytes from the Leishmune® vaccine produced high levels of IL-2, whereas a prominent type 1 immune response was the hallmark of the LBSap vaccine, which presented high levels of IL-2, IL-6, TNF-α, and IFN-γ. The efficacy analysis using real-time polymerase chain reaction demonstrated a reduction in the parasitism in the spleen (Leishmune®: 64 %; LBSap: 42 %; and Leish-Tec®: 36 %) and liver (Leishmune®: 71 %; LBSap: 62 %; and Leish-Tec®: 48 %).ConclusionsThe dataset led to the conclusion that the LBSap vaccination was able to induce immune and efficacy profiles comparable with those of commercial vaccines, thus demonstrating its potential as a promising vaccine candidate for visceral leishmaniasis control.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1752-6) contains supplementary material, which is available to authorized users.

Schistosomiasis is a neglected parasitic disease that affects millions of people worldwide and is caused by helminth parasites from the genus Schistosoma. When caused by S. mansoni, it is associated with the development of a hepatosplenic disease caused by an intense immune response to the important antigenic contribution of adult worms and to the presence of eggs trapped in liver tissue. Although the importance of the spleen for the establishment of immune pathology is widely accepted, it has received little attention in terms of the molecular mechanisms operating in response to the infection. Here, we interrogated the spleen proteome using a label-free shotgun approach for the potential discovery of molecular mechanisms associated to the peak of the acute phase of inflammation and the development of splenomegaly in the murine model. Over fifteen hundred proteins were identified in both infected and control individuals and 325 of those proteins were differentially expressed. Two hundred and forty-two proteins were found upregulated in infected individuals while 83 were downregulated. Functional enrichment analyses for differentially expressed proteins showed that most of them were categorized within pathways of innate and adaptive immunity, DNA replication, vesicle transport and catabolic metabolism. There was an important contribution of granulocyte proteins and antigen processing and presentation pathways were augmented, with the increased expression of MHC class II molecules but the negative regulation of cysteine and serine proteases. Several proteins related to RNA processing were upregulated, including splicing factors. We also found indications of metabolic reprogramming in spleen cells with downregulation of proteins related to mitochondrial metabolism. Ex-vivo imunophenotyping of spleen cells allowed us to attribute the higher abundance of MHC II detected by mass spectrometry to increased number of macrophages (F4/80+/MHC II+ cells) in the infected condition. We believe these findings add novel insights for the understanding of the immune mechanisms associated with the establishment of schistosomiasis and the processes of immune modulation implied in the host-parasite interactions.

Autoantibodies specific for alpha-fodrin fragments are found in the tissues of persons afflicted with Sjögren's syndrome (SS). However, the mechanism for alpha-fodrin degradation remains elusive. The following experiments utilized Par C5 cells to examine the role of P2X7 receptor (P2X7R) in apoptosis, particularly in the cleavage and release of alpha-fodrin, an apparent SS autoantigen. Five mM ATP stimulation induced apoptotic cell death with a sustained Ca2+ influx, which was mimicked in HEK cells transfected with P2X7R. ATP also induced cleavage of alpha-fodrin mediated by caspase-3 and calpain, releasing alpha-fodrin fragments through membrane blebs. However, both apoptotic cell death and alpha-fodrin cleavage were inhibited in the presence of 300 microM oxidized-ATP (ox-ATP), an irreversible blocker of P2X7R, or in Ca(2+)-free solution. We concluded that P2X7R plays an important role in apoptosis and alpha-fodrin degradation in salivary epithelial cells, providing an important clue elucidating the presence of alpha-fodrin fragments in SS tissues.

Extracellular adenosine plays important roles in modulating the immune responses.We have previously demonstrated that infection of dendritic cells (DC) by Leishmania amazonensis leads to increased expression of CD39 and CD73 and to the selective activation of the low affinity A 2B receptors (A 2B R), which contributes to DC inhibition, without involvement of the high affinity A 2A R. To understand this apparent paradox, we now characterized the alterations of both adenosine receptors in infected cells. With this aim, bone marrow-derived DC from C57BL/6J mice were infected with metacyclic promastigotes of L. amazonensis. Fluorescence microscopy revealed that L. amazonensis infection stimulates the recruitment of A 2B R, but not of A 2A R, to the surface of infected DC, without altering the amount of mRNA or the total A 2B R density, an effect dependent on lipophosphoglycan (LPG). Log-phase promastigotes or axenic amastigotes of L. amazonensis do not stimulate A 2B R recruitment. A 2B R clusters are localized in caveolin-rich lipid rafts and the disruption of these membrane domains impairs A 2B R recruitment and activation. More importantly, our results show that A 2B R co-localize with CD39 and CD73 forming a "purinergic cluster" 2 of 16 | FIGUEIREDO Et al.