Immune Evasion Strategies of<i>Trypanosoma cruzi</i>

Nardy, Ana Flávia Fernandes Ribas; Freire-de-Lima, Célio Geraldo; Morrot, Alexandre

doi:10.1155/2015/178947

Cited by 53 publications

(34 citation statements)

References 99 publications

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“…Survival of T. cruzi in the host depends on it escaping from immune recognition and/or it evading immune effector mechanisms. Several studies revealed that proteins secreted by the protozoan in the bloodstream, glycosylphosphatidylinositol-mucins molecules present in the parasite surface, and the blockade of complement pathways are strategies used by T. cruzi to escape immune recognition and delay the progression of immune response ( 52 – 54 ). The capacity of the parasite to survive has been attributed to the suppression of immune responsiveness.…”

Section: Discussionmentioning

confidence: 99%

CD86 Expression by Monocytes Influences an Immunomodulatory Profile in Asymptomatic Patients with Chronic Chagas Disease

et al. 2018

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In the chronic phase of Chagas disease, 60% of the patients develop the asymptomatic form known as indeterminate (IND). The remaining 30% of the patients develop a life-threatening form in which digestive and/or cardiac (CARD) alterations take place. The mechanisms underlying the development of severe forms of Chagas disease remain poorly understood. It is well known that interactions between immune cells such as monocytes and lymphocytes drive immune responses. Further, the co-stimulatory molecules CD80 and CD86 expressed by monocytes and subsets induce lymphocyte activation, thereby triggering cellular immune response. Here, we revealed, for the first time, the functional-phenotypic profile of monocytes subsets in Chagas disease. Using flow cytometry, we evaluated the effect of in vitro stimulation with Trypanosoma cruzi antigens on the expression of the co-stimulatory molecules CD80 and CD86 in different monocyte subsets of patients with IND and CARD clinical forms of Chagas disease. We also assessed the expression of toll-like receptor (TLR)-2, TLR-4, TLR-9, HLA-DR, IL-10, and IL-12 in the monocyte subsets and of CTLA-4 and CD28, ligands of CD80 and CD86, in T lymphocytes. CD86 expression in all monocyte subsets was higher in IND patients when compared with non-infected (NI) individuals. After stimulation with T. cruzi, these patients also showed a higher frequency of CD4+CTLA-4+ T lymphocytes than NI individuals. We found an association between CD80 and CD28, and between CD86 and CTLA-4 expression, with a high frequency of regulatory T (Treg) cells in IND patients. We proposed that CD86 may be involved in immunoregulation by its association with CTLA-4 in asymptomatic patients. CD86 and CTLA-4 interaction may influence Treg activation, and this could represent a new strategy to control inflammation and tissue damage.

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Section: Discussionmentioning

confidence: 99%

CD86 Expression by Monocytes Influences an Immunomodulatory Profile in Asymptomatic Patients with Chronic Chagas Disease

et al. 2018

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“…Regardless of whether a cell is infected by viruses, bacteria, protozoa, or fungi, the pathogen in each case uses the immune system to modulate the response and, thereby, survive inside the cell. [163][164][165] Bacteria and protozoa One of the key issues arising from the discussion of this subject is understanding the response that PRRs can induce through the recognition of PAMPs of certain microorganisms. Classically, receptors such as those in the Toll family agglutinate a variable range from TLR1 to TLR13.…”

Section: Mechanisms Of Immune Evasion Used By Intracellular Pathogensmentioning

confidence: 99%

<p>Functional aspects, phenotypic heterogeneity, and tissue immune response of macrophages in infectious diseases</p>

Sousa¹,

Vasconcelos²,

Quaresma³

2019

IDR

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Macrophages are a functionally heterogeneous group of cells with specialized functions depending not only on their subgroup but also on the function of the organ or tissue in which the cells are located. The concept of macrophage phenotypic heterogeneity has been investigated since the 1980s, and more recent studies have identified a diverse spectrum of phenotypic subpopulations. Several types of macrophages play a central role in the response to infectious agents and, along with other components of the immune system, determine the clinical outcome of major infectious diseases. Here, we review the functions of various macrophage phenotypic subpopulations, the concept of macrophage polarization, and the influence of these cells on the evolution of infections. In addition, we emphasize their role in the immune response in vivo and in situ, as well as the molecular effectors and signaling mechanisms used by these cells. Furthermore, we highlight the mechanisms of immune evasion triggered by infectious agents to counter the actions of macrophages and their consequences. Our aim here is to provide an overview of the role of macrophages in the pathogenesis of critical transmissible diseases and discuss how elucidation of this relationship could enhance our understanding of the host–pathogen association in organ-specific immune responses.

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“…By a general mechanism known as colonization resistance (87)(88)(89), members of the gut microbiota are thought to antagonize pathogens. Production of bacteriocidins or peroxidases can inhibit or kill pathogenic bacteria.…”

Section: Figmentioning

confidence: 99%

Giardia Alters Commensal Microbial Diversity throughout the Murine Gut

et al. 2017

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Giardia lamblia is the most frequently identified protozoan cause of intestinal infection. Over 200 million people are estimated to have acute or chronic giardiasis, with infection rates approaching 90% in areas where Giardia is endemic. Despite its significance in global health, the mechanisms of pathogenesis associated with giardiasis remain unclear, as the parasite neither produces a known toxin nor induces a robust inflammatory response. Giardia colonization and proliferation in the small intestine of the host may, however, disrupt the ecological homeostasis of gastrointestinal commensal microbes and contribute to diarrheal disease associated with giardiasis. To evaluate the impact of Giardia infection on the host microbiota, we used culture-independent methods to quantify shifts in the diversity of commensal microbes throughout the gastrointestinal tract in mice infected with Giardia. We discovered that Giardia's colonization of the small intestine causes a systemic dysbiosis of aerobic and anaerobic commensal bacteria. Specifically, Giardia colonization is typified by both expansions in aerobic Proteobacteria and decreases in anaerobic Firmicutes and Melainabacteria in the murine foregut and hindgut. Based on these shifts, we created a quantitative index of murine Giardia-induced microbial dysbiosis. This index increased at all gut regions during the duration of infection, including both the proximal small intestine and the colon. Giardiasis could be an ecological disease, and the observed dysbiosis may be mediated directly via the parasite's unique anaerobic fermentative metabolism or indirectly via parasite induction of gut inflammation. This systemic alteration of murine gut commensal diversity may be the cause or the consequence of inflammatory and metabolic changes throughout the gut. Shifts in the commensal microbiota may explain observed variations in giardiasis between hosts with respect to host pathology, degree of parasite colonization, infection initiation, and eventual clearance.KEYWORDS Giardia, microbiome, parasite, pathogenesis G iardia lamblia is a microaerophilic protozoan parasite of humans and animals that causes significant morbidity and diarrheal disease worldwide (1, 2). Giardiasis is a zoonotic disease with diverse animal reservoirs. Parasites infect and complete their life cycle in mammalian hosts, and infected animals shed Giardia cysts into water supplies. Over 200 million people are estimated to have acute or chronic giardiasis, and rates of giardiasis approach 90% in areas where it is endemic (3, 4). When prevalent, giardiasis has been implicated as a primary cause of growth restriction for children, resulting in long-term consequences, such as stunting, failure to thrive, malnutrition, and cognitive disabilities (1, 2, 5). In addition, Giardia has been associated with substantial postclearance irritable bowel symptoms in both children and adults (1, 6-8). The significant and adverse impact of giardiasis on global human health contrasts with a considerable lack of resea...

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Immune Evasion Strategies ofTrypanosoma cruzi

Cited by 53 publications

References 99 publications

CD86 Expression by Monocytes Influences an Immunomodulatory Profile in Asymptomatic Patients with Chronic Chagas Disease

CD86 Expression by Monocytes Influences an Immunomodulatory Profile in Asymptomatic Patients with Chronic Chagas Disease

<p>Functional aspects, phenotypic heterogeneity, and tissue immune response of macrophages in infectious diseases</p>

Giardia Alters Commensal Microbial Diversity throughout the Murine Gut

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