Co-expression of human sialyltransferase improves N-glycosylation in Leishmania tarentolae and optimizes the production of humanized therapeutic glycoprotein IFN-beta.

The production of therapeutic glycoproteins is primarily expensive due to the necessity of culturing mammalian cells. These systems often require complex and costly culture media and typically yield low amounts of protein. Leishmania tarentolae, a non-pathogenic protozoan to mammals, has emerged as a cost-effective alternative system for heterologous glycoprotein expression due to its suitability for large-scale production using low-cost culture media, and its ability to perform mammalian-like post-translational modifications, including glycosylation.

Public engagement for the conduct of a controlled human infection study testing vaccines against Necator americanus (hookworm) in areas of active hookworm transmission in Brazil.

Unlabelled: Controlled Human Infection Models (CHIS) involve administering human pathogens to healthy participants in controlled medical settings, which can elicit complex bioethical issues. Understanding how the community perceives such studies can significantly increase the participant's sense of cooperation and increases the researcher's and the participant's transparency. The current study describes the development of an educational intervention to achieve these ends as it aims to (1) analyze perceptions of the Controlled Human Infection Studies (CHIS), and (2) evaluate the participants' comprehension of the CHIS.

Retrospective cohort study to evaluate the continuous use of anticholesterolemics and diuretics in patients with COVID-19.

Purpose: The purpose of this study is to evaluate the interference of the continuous use of drug classes in the expression of biomarkers during the first week of hospitalization and in the prognosis of patients with COVID-19.

Methods: The patients diagnosed with COVID-19 and confirmed with SARS-CoV-2 by RT-qPCR assay underwent the collection of fasting whole blood samples for further analysis. Other data also extracted for this study included age, sex, clinical symptoms, related comorbidities, smoking status, and classes of continuous use.

Deletion of MIF gene from live attenuated LdCen parasites enhances protective CD4 T cell immunity.

Vaccination with live attenuated Leishmania parasites such as centrin deleted Leishmania donovani (LdCen) against visceral leishmaniasis has been reported extensively. The protection induced by LdCen parasites was mediated by both CD4 and CD8 T cells. While the host immune mediators of protection are known, parasite determinants that affect the CD4 and CD8 T cell populations remain unknown.

The role of environmental enteric dysfunction in the pathogenesis of Schistosoma mansoni-associated morbidity in school-aged children.

Background: Studies have implicated schistosomiasis as a cause of intestinal barrier disruption, a salient feature of environmental enteric dysfunction (EED), as eggs translocate from the sterile bloodstream through the gut wall. We examined the longitudinal impact of praziquantel (PZQ) treatment on a) EED biomarkers and b) Insulin growth factor I (IGF-1), a key driver of childhood linear growth, since EED has been implicated in linear growth stunting.

Methodology: 290 children infected with S.

Design and production of dengue virus chimeric proteins useful for developing tetravalent vaccines.

Dengue virus (DENV) is a Flavivirus estimated to cause 390 million infections/year. Currently, there is no anti-viral specific treatment for dengue, and efficient DENV vector control is still unfeasible. Here, we designed and produced chimeric proteins containing potential immunogenic epitopes from the four DENV serotypes in an attempt to further compose safer, balanced tetravalent dengue vaccines.

Growth arrested live-attenuated Leishmania infantum KHARON1 null mutants display cytokinesis defect and protective immunity in mice.

There is no safe and efficacious vaccine against human leishmaniasis available and live attenuated vaccines have been used as a prophylactic alternative against the disease. In order to obtain an attenuated Leishmania parasite for vaccine purposes, we generated L. infantum KHARON1 (KH1) null mutants (ΔLikh1).

HIV aspartyl protease inhibitors modify the percentage of activated leukocytes, as well as serum levels of IL-17A and NO during experimental leishmaniasis.

HIV aspartyl protease inhibitors are able to modulate multiple defense mechanisms. However, their influence on the immune response against Leishmania has rarely been investigated. The aim of our study was to investigate whether in vivo treatment with HIV aspartyl protease inhibitors is able to modulate the immune response during Leishmania infection.

Immunoregulatory mechanisms in Chagas disease: modulation of apoptosis in T-cell mediated immune responses.

Background: Chronic Chagas disease presents different clinical manifestations ranging from asymptomatic (namely indeterminate) to severe cardiac and/or digestive. Previous results have shown that the immune response plays an important role, although no all mechanisms are understood. Immunoregulatory mechanisms such as apoptosis are important for the control of Chagas disease, possibly affecting the morbidity in chronic clinical forms.

Application of rapid in vitro co-culture system of macrophages and T-cell subsets to assess the immunogenicity of dogs vaccinated with live attenuated Leishmania donovani centrin deleted parasites (LdCen-/-).

Background: Live attenuated Leishmania donovani parasites as LdCen(-/-) were shown to confer protective immunity against Leishmania infection in mice, hamsters, and dogs. Strong immunogenicity in dogs vaccinated with LdCen(-/-) has been previously reported, including increased antibody response favoring Th1 response lymphoproliferative responses, CD4(+) and CD8(+) T-cells activation, increased levels of Th1 and reduction of Th2 cytokines, in addition to a significant reduction in parasite burden after 18 and 24 months post virulent parasite challenge.

Methods: Aimed at validating a new method using in vitro co-culture systems with macrophages and purified CD4(+) or CD8(+) or CD4(+):CD8(+) T-cells of immunized dogs with both LdCen(-/-) and Leishmune® to assess microbicide capacity of macrophages and the immune response profile as the production of IFN-γ, TNF-α, IL-12, IL-4 and IL-10 cytokines.

Intradermal Immunization of Leishmania donovani Centrin Knock-Out Parasites in Combination with Salivary Protein LJM19 from Sand Fly Vector Induces a Durable Protective Immune Response in Hamsters.

Background: Visceral leishmaniasis (VL) is a neglected tropical disease and is fatal if untreated. There is no vaccine available against leishmaniasis. The majority of patients with cutaneous leishmaniasis (CL) or VL develop a long-term protective immunity after cure from infection, which indicates that development of an effective vaccine against leishmaniasis is possible.

Vaccination using live attenuated Leishmania donovani centrin deleted parasites induces protection in dogs against Leishmania infantum.

Live attenuated Leishmania donovani parasites such as LdCen(-/-) have been shown elicit protective immunity against leishmanial infection in mice and hamster models. Previously, we have reported on the induction of strong immunogenicity in dogs upon vaccination with LdCen(-/-) including an increase in immunoglobulin isotypes, higher lymphoproliferative response, higher frequencies of activated CD4(+) and CD8(+) T cells, IFN-γ production by CD8(+) T cells, increased secretion of TNF-α and IL-12/IL-23p40 and, finally, decreased secretion of IL-4. To further explore the potential of LdCen(-/-) parasites as vaccine candidates, we performed a 24-month follow up of LdCen(-/-) immunized dogs after challenge with virulent Leishmania infantum, aiming determination of parasite burden by qPCR, antibody production (ELISA) and cellular responses (T cell activation and cytokine production) by flow cytometry and sandwich ELISA.

Arginine Supplementation Induces Arginase Activity and Inhibits TNF-α Synthesis in Mice Spleen Macrophages After Intestinal Obstruction.

Background: The purpose of this study was to assess the effect of arginine supplementation on arginase activity, tumor necrosis factor-α (TNF-α) and interleukin-10 (IL-10) synthesis in cultured splenic macrophages from a murine model of intestinal obstruction (IO). The effects of nitric oxide synthase (iNOS) inhibition were also studied using iNOS knockout animals.

Material And Methods: Male C57BL6/J wild-type (WT) and iNOS knockout (iNOS-/-) mice were randomized into 6 groups: Sham and Sham-/- (standard chow), IO and IO-/- (standard chow + IO), and Arg and Arg-/- (standard chow supplemented with arginine + IO).

Inflammatory mediators from monocytes down-regulate cellular proliferation and enhance cytokines production in patients with polar clinical forms of Chagas disease.

Exposure to Trypanosoma cruzi parasites induces monocytes and macrophages to produce various endogenous mediators, including prostaglandins and cytokines. To clarify the involvement of monocytes as an important source of inflammatory mediators in Chagas disease patients, we evaluated PBMC before and after depletion of adherent cells (monocytes) from patients with indeterminate (IND) and cardiac (CARD) clinical forms and from non-infected individuals (NI). We demonstrated that after the partial depletion of adherent cells, production of PGE2 was slightly decreased in patients with Chagas disease.

Induction of immunogenicity by live attenuated Leishmania donovani centrin deleted parasites in dogs.

Zoonotic visceral leishmaniasis, caused by the intracellular protozoan parasite Leishmania infantum, is a neglected tropical disease that is often fatal when untreated. Dogs are considered the main reservoir of L. infantum in zoonotic VL as the presence of infected dogs may increase the risk for human infection.

Cell apoptosis induced by hookworm antigens: a strategy of immunomodulation.

While several mechanisms of immunoregulation have been demonstrated for hookworm and other neglected tropical infections, the influence of apoptosis in the immunomodulation of hookworm infection is still poorly understood. In this study, we demonstrate the cytotoxic and pro-apoptotic activity of hookworm antigens in Jurkat T cells, mesenteric lymph nodes lymphocytes of healthy and hookworm-infected hamsters and during human natural infection. Our results showed that in vitrostimulation of Jurkat T cells with antigens induces a significant decrease of cell viability leading to a relevant increase of apoptotic cells.

The role of L-arginine and inducible nitric oxide synthase in intestinal permeability and bacterial translocation.

Background: Arginine has been shown to have several immunological and trophic properties in stressful diseases. Its metabolites, nitric oxide (NO) and polyamines, are related to arginine's effects. Thus, the aim of this study was to determine the effects of the NO donor L-arginine and the role of inducible NO synthase (iNOS) on intestinal permeability and bacterial translocation in a model of intestinal obstruction (IO) induced by a simple knot in the terminal ileum.

Induction of CD4(+)CD25(+)FOXP3(+) regulatory T cells during human hookworm infection modulates antigen-mediated lymphocyte proliferation.

Hookworm infection is considered one of the most important poverty-promoting neglected tropical diseases, infecting 576 to 740 million people worldwide, especially in the tropics and subtropics. These blood-feeding nematodes have a remarkable ability to downmodulate the host immune response, protecting themselves from elimination and minimizing severe host pathology. While several mechanisms may be involved in the immunomodulation by parasitic infection, experimental evidences have pointed toward the possible involvement of regulatory T cells (Tregs) in downregulating effector T-cell responses upon chronic infection.

Hookworm products ameliorate dextran sodium sulfate-induced colitis in BALB/c mice.

Background: Several lines of evidence have shown that helminthiasis can significantly reduce disease severity in animal models of intestinal inflammation, airway inflammation/hyperreactivity, diabetes, and multiple sclerosis. Identification and characterization of helminth-derived immunomodulatory molecules that contribute to anticolitis effects could lead to new therapeutic approaches in inflammatory bowel diseases (IBDs) without the need for helminth infection. We evaluated the therapeutic potential of adult human hookworm, Ancylostoma ceylanicum, crude (Aw) and excreted/secreted (ES) products on dextran sulfate sodium (DSS)-induced colitis in BALB/c mice.

Profile of central and effector memory T cells in the progression of chronic human chagas disease.

Background: Chronic Chagas disease presents several different clinical manifestations ranging from asymptomatic to severe cardiac and/or digestive clinical forms. Several studies have demonstrated that immunoregulatory mechanisms are important processes for the control of the intense immune activity observed in the chronic phase. T cells play a critical role in parasite specific and non-specific immune response elicited by the host against Trypanosoma cruzi.