Matheus Fernandes Costa-Silva

Booster dose after 10 years is recommended following 17DD-YF primary vaccination

A single vaccination of Yellow Fever vaccines is believed to confer life-long protection. In this study, results of vaccinees who received a single dose of 17DD-YF immunization followed over 10 y challenge this premise. YF-neutralizing antibodies, subsets of memory T and B cells as well as cytokine-producing lymphocytes were evaluated in groups of adults before (NVday0) and after (PVday30-45, PVyear1-4, PVyear5-9, PVyear10-11, PVyear12-13) 17DD-YF primary vaccination. YF-neutralizing antibodies decrease significantly from PVyear1-4 to PVyear12-13 as compared to PVday30-45, and the seropositivity rates (PRNT≥2.9Log10mIU/mL) become critical (lower than 90%) beyond PVyear5-9. YF-specific memory phenotypes (effector T-cells and classical B-cells) significantly increase at PVday30-45 as compared to naïve baseline. Moreover, these phenotypes tend to decrease at PVyear10-11 as compared to PVday30-45. Decreasing levels of TNF-α+ and IFN-γ+ produced by CD4+ and CD8+ T-cells along with increasing levels of IL-10+CD4+T-cells were characteristic of anti-YF response over time. Systems biology profiling represented by hierarchic networks revealed that while the naïve baseline is characterized by independent micro-nets, primary vaccinees displayed an imbricate network with essential role of central and effector CD8+ memory T-cell responses. Any putative limitations of this cross-sectional study will certainly be answered by the ongoing longitudinal population-based investigation. Overall, our data support the current Brazilian national immunization policy guidelines that recommend one booster dose 10 y after primary 17DD-YF vaccination.

Eosinophil activation status, cytokines and liver fibrosis in Schistosoma mansoni infected patients

We have been investigating whether human eosinophils play an important role in schistosomiasis mansoni morbidity. Our main focus has been on the activation-related cell surface markers (CD23/CD69/CD25/HLA-DR/CD28/CD80) and the detection of TNF-alpha, IL-4 and IL-5 in peripheral blood eosinophils from chronic Schistosoma mansoni-infected patients. Our studies compare both, intestinal (INT) and individuals with periportal fibrosis (FIB). Our major findings, point to distinct profile of activation-related surface markers on eosinophils as the hallmark of disease morbidity during chronic S. mansoni infection. Up-regulation of several activation-related markers was observed on eosinophils from FIB group, but not INT, which include early activation markers, such as CD69 and CD23. INT displayed a distinct profile, with up-regulation of molecules related to the late activation (CD25, HLA-DR, CD28 and CD80). These results suggest that some immunoregulatory events may take place controlling the early eosinophil activation in the INT group. Higher levels of eosinophil-derived cytokines were observed in FIB, regardless the antigen stimulation in vitro. A mixed cytokine pattern, characterized by positive correlation between TNF-alpha, IL-4 and IL-5 was observed in both INT and FIB. However, lack of correlation between the cytokine expression and the eosinophil activation status points out that even those FIB patients presenting minor increment on eosinophil activation displayed higher levels of cytokine-positive eosinophils. Indeed, the positive association between lymphocyte-derived IL-10 and the eosinophils cytokine profile was observed exclusively in INT further emphasize our hypothesis that immunoregulatory events take place controlling disease morbidity in human schistosomiasis. The impaired IL-10-driven immunoregulatory function may play an important role on the establishment of pathology in patients bearing periportal fibrosis.

Gene expression profile of cytokines and chemokines in skin lesions from Brazilian Indians with localized cutaneous leishmaniasis

Cutaneous leishmaniasis (CL) is a chronic inflammatory disease caused by dermotropic Leishmania species belonging to the Viannia subgenera, with Leishmania (V.) braziliensis considered the main agent in Brazil. After infection, a local inflammatory process is initiated, inducing the expression of several cytokine/chemokine genes. We evaluated the immunity to CL of patients living in the indigenous community Xakriabá, Minas Gerais state, Brazil, by performing detailed analyses of the mRNA expression of different cytokines and chemokines in CL lesions, considering the time evolution (recent or late). We also studied the profile of the inflammatory infiltrate by histopathological analysis. The histopathological features of recent CL lesions showed an intense inflammatory reaction, characterized by the presence of both mononuclear and polymorphonuclear cells, whereas late CL lesions exhibited a predominance of mononuclear leukocytes. The gene expression of cytokines/chemokines in skin biopsies from the CL group showed higher transcript levels of modulatory (IL10 and TGFB1), anti-inflammatory (IL4), and pro-inflammatory (TNF, IFNG, IL12B, CCL2, CCL3, CCL5, CXCL10) biomarkers in recent lesions than in late lesions. Our findings suggest that differential gene expression of cytokines and chemokines found in skin lesions from CL patients is associated with time evolution of lesions.

Seric chemokines and chemokine receptors in eosinophils during acute human schistosomiasis mansoni

The recruitment of circulating eosinophils by chemokines and chemokine receptors plays an important role in the inflammation process in acute human schistosomiasis. Our main focus has been on the plasma chemokines (CXCL8/CCL2/CCL3/CCL24) and chemokine receptors (CCR2/CCR3/CCR5/CXCR1/CXCR2/CXCR3/CXCR4) expressed by circulating eosinophils from acute Schistosoma mansoni infected patients (ACT). Our studies compared ACT patients and healthy individuals as a control group. Our major findings demonstrated a plethora of chemokine secretion with significantly increased secretion of all chemokines analysed in the ACT group. Although no differences were detected for beta-chemokine receptors (CCR2, CCR3 and CCR5) or alpha-chemokine receptors (CXCR3 and CXCR4), a significantly lower frequency of CXCR1+ and CXCR2+ eosinophils in the ACT group was observed. The association between chemokines and their chemokine receptors revealed that acutely infected schistosome patients displaying decreased plasma levels of CCL24 are the same patients who presented enhanced secretion of CCL3, as well as increased expression of both the CCR5 and CXCR3 chemokine receptors. These findings suggest that CCL24 may influence the kinetics of chemokines and their receptors and eosinophils recruitment during human acute schistosomiasis mansoni.

Cytokine Pattern of T Lymphocytes in Acute Schistosomiasis mansoni Patients following Treated Praziquantel Therapy

Acute schistosomiasis is associated with a primary exposure and is more commonly seen in nonimmune individuals traveling through endemic regions. In this study, we have focused on the cytokine profile of T lymphocytes evaluated in circulating leukocytes of acute Schistosomiasis mansoni-infected patients (ACT group) before and after praziquantel treatment (ACT-TR group). Our data demonstrated increased values of total leukocytes, eosinophils, and monocytes in both groups. Interestingly, we have observed that patients treated with praziquantel showed increased values of lymphocytes as compared with noninfected group (NI) or ACT groups. Furthermore, a decrease of neutrophils in ACT-TR was observed when compared to ACT group. Analyses of short-term in vitro whole blood stimulation demonstrated that, regardless of the presence of soluble Schistosoma mansoni eggs antigen (SEA), increased synthesis of IFN-γ and IL-4 by T-cells was observed in the ACT group. Analyses of cytokine profile in CD8 T cells demonstrated higher percentage of IFN-γ and IL-4 cells in both ACT and ACT-TR groups apart from increased percentage of IL-10 cells only in the ACT group. This study is the first one to point out the relevance of CD8 T lymphocytes in the immune response induced during the acute phase of schistosomiasis.

Protective Profile Involving CD23/IgE-mediated NO Release is a Hallmark of Cutaneous Leishmaniasis Patients from the Xakriabá Indigenous Community in Minas Gerais, Brazil

In this study, we described, for the first time, specific aspects of an anti‐Leishmania immune response in a Brazilian Xakriabá indigenous community. Induction of an intracellular NO pathway, triggered by the binding of IgE to CD23 receptor in IFN‐γ/IL‐4 cytokines environment, was evaluated in localized cutaneous leishmaniasis (LCL) carriers and positive Montenegro skin test (MST) individuals without skin lesion (MT+SL−). Our data demonstrated that the higher frequency of CD23+CD14+ monocytes and the increased serum levels of IgE observed in the LCL group were even higher in LCL carriers with late lesions (LCL≥60). Furthermore, patients with LCL presented increased NO production after Leishmania (Viannia) braziliensis stimulation and this NO profile was independent of the time of the lesion (recent LCL<60 or late LCL≥60). We also showed that the increased frequency of IFN‐γ+ and IL‐4+CD4+ T cells is related to the MT+SL− group. The results of biomarker signature curves demonstrated that in the MT+SL− group, the index signature was characterized by DAF‐2T+CD14+/IL‐4+CD8+/IFN‐γ+CD4+/IL‐4+CD4+. On the other hand, the LCL group presented a higher index of DAF‐2T+CD14+/CD23+CD14+/IL‐4+ CD8+, associated with a lower index of IFN‐γ+CD8+. Considering the time of lesion, data analysis demonstrated that the main differences observed were highlighted in LCL<60 patients, with a higher index of CD23+CD14+, which was also present in LCL≥60 patients. In conclusion, our data suggest that the protective immune response involving CD23‐IgE‐mediated NO release is a hallmark of patients with LCL. However, in MT+SL− individuals, another different leishmanicidal mechanism seems to be involved.

Identification of Anti-Trypanosoma cruzi Lead Compounds with Putative Immunomodulatory Activity

ABSTRACT In seeking substitutions for the current Chagas disease treatment, which has several relevant side effects, new therapeutic candidates have been extensively investigated. In this context, a balanced interaction between mediators of the host immune response seems to be a key element for therapeutic success, as a proinflammatory microenvironment modulated by interleukin-10 (IL-10) is shown to be relevant to potentiate anti-Trypanosoma cruzi drug activity. This study aimed to identify the potential immunomodulatory activities of the anti-T. cruzi K777, pyronaridine (PYR), and furazolidone (FUR) compounds in peripheral blood mononuclear cells (PBMC) from noninfected (NI) subjects and chronic Chagas disease (CD) patients. Our results showed low cytotoxicity to PBMC populations, with 50% cytotoxic concentrations (CC50) of 71.0 μM (K777), 9.0 μM (PYR), and greater than 20 μM (FUR). In addition, K777 showed no impact on the exposure index (EI) of phytohemagglutinin-stimulated leukocytes (PHA), while PYR and FUR treatments induced increased EI of monocytes and T lymphocytes at late stages of apoptosis in NI subjects. Moreover, K777 induced a more prominent proinflammatory response (tumor necrosis factor alpha-positive [TNF-α+] CD8+/CD4+, gamma interferon-positive [IFN-γ+] CD4+/CD8+ modulated by interleukin-10-positive [IL-10+] CD4+ T/CD8+ T) than did PYR (TNF-α+ CD8+, IL-10+ CD8+) and FUR (TNF-α+ CD8+, IL-10+ CD8+). Signature analysis of intracytoplasmic cytokines corroborated the proinflammatory/modulated (K777) and proinflammatory (PYR and FUR) profiles previously found. In conclusion, the lead compound K777 may induce beneficial changes in the immunological profile of patients presenting the chronic phase of Chagas disease and may contribute to a more effective therapy against the disease.

Infection of hematopoietic stem cells by Leishmania infantum increases erythropoiesis and alters the phenotypic and functional profiles of progeny

Immunosuppression is a well-established risk factor for Visceral Leishmaniasis. Post-immunosuppression leishmaniasis is characterized by an increase of parasite burden, hematopoietic disorders and unusual clinical manifestations. Although there are many reports on bone marrow findings in VL, less is known about the relationship between parasite dynamics in this organ and the function of either hematopoietic stem cells and progenitor cells themselves. In the present study, we tackle these issues using a new approach of infecting human stem cells derived from bone marrow with L. infantum. Using this strategy, we show that human hematopoietic stem cells (hHSC) are able to phagocytize L. infantum promastigotes and release modulatory and pro-inflammatory cytokines, mainly TNF-α. Our results demonstrated that L. infantum infection in vitro enhances hematopoiesis, favoring the development of erythrocitic lineage through a mechanism yet unknown. Moreover, we found that L. infantum infection alters the phenotypic profile of the hematopoietic progeny; modifying the surface markers expression of differentiated cells. Thus, our study represents a rare opportunity to monitor the in vitro differentiation of human stem cells experimentally infected by L. infantum to better understand the consequences of the infection on phenotypic and functional profile of the cell progeny.

Clinical, Laboratory and Ultrasonographic Evaluation of Patients with Acute Schistosomiasis Mansoni

Schistosomiasis is a parasite chronic disease caused by the helminth of genus Schistosoma. The infection is common in parts of Africa, South America, Middle East, Caribbean and Asia where it is a leading cause of morbidity and mortality [1]. Recent estimates suggest there are 700 million people at risk worldwide with almost 200 million infected in Africa alone [2]. In Brazil, the schistosomiasis infection is caused by Schistosoma mansoni, where estimates suggest a range from 2.5 million [3, 4] to 12 million people infected [5]. In the state of Minas Gerais, schistoso‐ miasis mansoni is prevalent in 519 out of 853 municipalities, with an estimated number of one million infected people in an area of 300.000 km2 [6].