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Avaliação da atividade imunomoduladora de 'Alternanthera tenella' Colla e investigação de ações do extrato aquoso em modelo de artrite experimental; Evaluation of the immunomodulatory activity of Alternanthera tenella Colla. Effects of the aqueous extract investigated in an experimental arthritis model

Biella, Carla de Agostino
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 15/06/2007 PT
Relevância na Pesquisa
26%
Plantas do gênero Alternanthera (Amaranthaceae) vêm sendo estudadas por suas propriedades antiparasitária, antibacteriana e antiviral. No Brasil a planta Alternanthera tenella Colla, objeto de nossa investigação, é utilizada na medicina popular por possuir atividade antiinflamatória. Considerando a importância do sistema imunológico em infecções e em doenças auto-imunes sistêmicas que apresentam intensa reação inflamatória, o objetivo do atual estudo foi investigar a ação imunomoduladora de extratos de A. tenella no sistema imune de camundongos BALB/c e sua atividade em modelo de artrite experimental induzida pelo óleo mineral pristane (2,6,10,14-tetrametilpentadecano) em camundongos AIRmax, obtidos por seleção genética para reação inflamatória aguda máxima. Extratos brutos orgânicos (etanólico e hexânico), aquosos, frações e flavonóides foram inoculados via intraperitoneal em camundongos BALB/c imunizados ou não com eritrócitos de carneiro (EC). Efeitos imunomoduladores e imunotóxicos foram avaliados através da determinação do peso corporal e dos órgãos linfóides, celularidade do baço e de ensaios funcionais como enumeração de células formadoras de placas (PFC, plaque forming cells), produção de anticorpos anti-EC e edema de pata induzido por carragenina. Posteriormente foram avaliados os efeitos dos extratos aquosos nas subpopulações de linfócitos esplênicos (CD3...

Análise de anticorpos antiparasitários dosados em soro sanguíneo e sua relação com a presença de bandas oligoclonais em pacientes com esclerose múltipla; Analysis of antiparasitic antibodies measured In Blood serum and their selationship with the presence of oligoclonal bands in patients with multiple Sclerosis

Papavero, Fabiana Cruz Gomes da Fonseca
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 17/06/2013 PT
Relevância na Pesquisa
36.32%
Introdução: A frequência de detecção de bandas oligoclonais (BOC) em doentes com esclerose múltipla (EM) na cidade de São Paulo é significativamente mais baixa do que em outras cidades do Brasil e de outros países, principalmente da Europa e da América do Norte. Não se conhece o motivo pelo qual isso ocorre. Uma das hipóteses mais interessantes relacionada à imunopatogenia da EM é a chamada Hipótese Higiênica, que postula uma relação inversamente proporcional entre a prevalência de infecções por parasitas e a frequência da EM. Objetivo: verificar se há relação entre a ocorrência de anticorpos contra parasitas no soro sanguíneo e a detecção de BOC em pacientes diagnosticados com EM na cidade de São Paulo. Métodos: Foram estudados 164 pacientes do Ambulatório de Doenças Desmielinizantes da Divisão de Neurologia Clínica e da Divisão de Anestesia do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo dos quais foram obtidas as amostras de LCR e de soro em que foi realizado este estudo. Esses pacientes foram separados em 4 grupos (EM, CIS, Grupo Controle com Pacientes de DNI e Grupo Controle com Pacientes sem Queixas Neurológicas) nos quais foram identificadas as presenças de BOC e de anticorpos parasitários. Para a detecção de anticorpos parasitários...

Antiparasitic antibodies occur with similar frequency in patients with clinically established multiple sclerosis with or without oligoclonal bands in the cerebrospinal fluid

Fonseca-Papavero,Fabiana Cruz Gomes da; Callegaro,Dagoberto; Gama,Paulo Diniz da; Livramento,Jose Antonio; Vaz,Adelaide Jose; Machado,Luis dos Ramos
Fonte: Academia Brasileira de Neurologia - ABNEURO Publicador: Academia Brasileira de Neurologia - ABNEURO
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2013 EN
Relevância na Pesquisa
66.84%
The "hygiene hypothesis" postulates an inverse relationship between the prevalence of parasitic infections and the frequency of multiple sclerosis (MS). Objective: It was to study whether antibodies against parasites could be demonstrated more frequently in blood serum from MS patients with oligoclonal bands (OCB) than from MS patients without OCB. Methods: We studied serum samples from 164 patients who had previously been analyzed to investigate OCB. Parasitic antibodies were studied through unidimensional electrophoresis of proteins on polyacrylamide gel against Taenia antigens, searching for antiparasitic specific low molecular weight antibodies and also for antiparasitic nonspecific high molecular weight antibodies. Results: Two of the 103 patients with no evidence of OCB had antibodies of low molecular weight and 59 of them had antibodies of high molecular weight. Of the 61 patients with evidence of OCB, one showed antibodies of low molecular weight and 16 showed antibodies of high molecular weight. Conclusion: Antiparasitic antibodies are detected with similar frequency in MS patients with OCB and in MS patients without OCB.

The spatial distribution of Schistosoma mansoni infection before and after chemotherapy in the Jequitinhonha Valley in Brazil

Gazzinelli,Andrea; Hightower,Allen; LoVerde,Philip T; Haddad,João Paulo Amaral; Pereira,Wesley Rodrigues; Bethony,Jeffrey; Correa-Oliveira,Rodrigo; Kloos,Helmut
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2006 EN
Relevância na Pesquisa
26%
Schistosomiasis prevalence and egg counts remained low one year after chemotherapy in most households in a hyperendemic rural area in northern Minas Gerais but several distinct spatial patterns could be observed in relation to IgE levels and to a lesser extent to exposure risk (TBM) and type of water supply. An inverse relationship between pre-treatment household prevalence and egg counts on the one hand and post-treatment IgE levels on the other were noted in two of the five communities. Low exposure risk was associated with the low pre-treatment infection rates in the central village but did not contribute to the decline of infection rates after chemotherapy in the study area, as indicated by the significant increase in water contact during the posttreatment period (p < 0.0001). Distance between households and the streams and socioeconomic factors were also unimportant in predicting the spatial distribution of infection. These results are consistent with the production and antiparasitic effect of high levels of IgE in Schistosoma mansoni infection.

Role of P Glycoprotein in the Course and Treatment of Encephalitozoon Microsporidiosis

Leitch, Gordon J.; Scanlon, Mary; Shaw, Andrew; Visvesvara, Govinda S.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /01/2001 EN
Relevância na Pesquisa
16.25%
Encephalitozoon microsporidia are obligate intracellular protozoan parasites that proliferate and differentiate within a parasitophorous vacuole inside host cells that are usually epithelial in nature. Isolates of the three species of the Encephalitozoon microsporidia, E. cuniculi, E. hellem, and E. intestinalis, were obtained from AIDS patients and cultured in green monkey (E6) kidney cells. Anti-P-glycoprotein (anti-Pgp) and anti-multidrug resistance-associated protein (anti-MRP) monoclonal antibodies were used to probe for multidrug resistance (MDR) pump epitopes and verapamil- or cyclosporin A- and probenecid-modulated intracellular calcein fluorescence were used to assess the expression of Pgp and MRP respectively in uninfected and infected cells. Pgp, but not MRP, was detected immunocytochemically and by verapamil- and cyclosporin A-potentiated intracellular fluorescence in both host cells and parasite developing stages. When an in vitro infection assay was employed, verapamil and cyclosporin A acted as chemosensitizing agents for the antiparasitic drug albendazole. These observations suggest that inhibiting host cell and perhaps parasite MDR pumps may increase the efficacy of antiparasitic agents in these and other microsporidia species.

Antibody Responses of Cattle Immunized with the Tf190 Adhesin of Tritrichomonas foetus

Voyich, Jovanka M.; Ansotegui, Raymond; Swenson, Connie; Bailey, John; Burgess, Donald E.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /11/2001 EN
Relevância na Pesquisa
16%
The antibody response patterns of cattle after subcutaneous and intranasal immunizations with adhesin Tf190 of Tritrichomonas foetus were investigated. Reactions of antibody from cattle parenterally immunized with Tf190 revealed antigen specificity and Tf190 sensitization in the majority of the animals, as determined by Western blotting. The results also demonstrated strong preimmune immunoglobulin G2 (IgG2) binding to T. foetus antigens not seen in IgG1 profiles. Subcutaneous injections of Tf190 resulted in significant (P < 0.05) increases in serum IgG1 and IgG2 titers over time, as determined by parasite specific enzyme-linked immunosorbent assay. Immune sera also significantly inhibited parasite adhesion to mammalian cell lines compared to the level of inhibition obtained with preimmune sera (P < 0.05). Intranasal immunization with Tf190 failed to produce measurable parasite-specific antibody in serum; however, this immunization route did result in significant (P < 0.05) increases in parasite-specific IgA titers in cervical mucus secretions from immunized animals that were more resistant to intravaginal challenge with T. foetus than controls. These results suggest that systemic immunization with Tf190 results in serum antibody production and antiparasitic adhesin antibodies. Additionally...

Dominance of Immunoglobulin G2c in the Antiphosphorylcholine Response of Rats Infected with Trichinella spiralis

Peters, Philip J.; Gagliardo, Lucille F.; Sabin, Elizabeth A.; Betchen, Arin B.; Ghosh, Kaya; Oblak, Jeb B.; Appleton, Judith A.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /09/1999 EN
Relevância na Pesquisa
16.26%
The antibody response to the L1 stage of Trichinella spiralis has been described as biphasic. Worms resident in the intestine during the first week of infection stimulate an antibody response against a subset of larval proteins. L1 larvae in the muscle at the end stage of infection stimulate a second antibody response against tyvelose-bearing glycoproteins. Antityvelose antibodies protect rats against challenge infection with larvae. The aim of this study was to characterize the rat B-cell response against larval antigens during the intestinal phase of T. spiralis infection and to test the antiparasitic effects of such antibodies. Strain PVG rats were infected orally with 500 larvae. Antibodies specific for phosphorylcholine-bearing proteins of L1 larvae first appeared in serum 9 days postinfection. Absorption experiments showed that the majority of antilarval antibodies produced in rats 16 days after infection with T. spiralis were specific for phosphorylcholine-bearing proteins. A fraction of these antibodies bound to free phosphorylcholine. Immunoglobulin G2c (IgG2c) producing cells in the mesenteric lymph node dominated this early antibody response. IgG2c is associated with T-independent immune responses in the rat; however, a comparison of athymic rats with euthymic controls suggested that only a small fraction of the phosphorylcholine-related antibody response against T. spiralis was T independent. Phosphorylcholine is a common epitope in antigens of bacteria and nematode parasites and has been shown to be a target of protective immunity in certain bacteria. A monoclonal IgG2c antibody was prepared from infected rats and shown to be specific for phosphorylcholine. Monoclonal phosphorylcholine-specific IgG2c failed to protect rats against intestinal infection with T. spiralis. Therefore...

Incidence of Toxoplasma gondii Infection in 35,940 Pregnant Women in Norway and Pregnancy Outcome for Infected Women

Jenum, Pål A.; Stray-Pedersen, Babill; Melby, Kjetil K.; Kapperud, Georg; Whitelaw, Andrew; Eskild, Anne; Eng, Jan
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /10/1998 EN
Relevância na Pesquisa
16%
From 1992 to 1994 a screening program for detection of specific Toxoplasma gondii antibodies involving 35,940 pregnant women was conducted in Norway. For women with serological evidence of primary T. gondii infection, amniocentesis and antiparasitic treatment were offered. The amniotic fluid was examined for T. gondii by PCR and mouse inoculation to detect fetal infection. Infants of infected mothers had clinical and serological follow-up for at least 1 year to detect congenital infection. Of the women 10.9% were infected before the onset of pregnancy. Forty-seven women (0.17% among previously noninfected women) showed evidence of primary infection during pregnancy. The highest incidence was detected (i) among foreign women (0.60%), (ii) in the capital city of Oslo (0.46%), and (iii) in the first trimester (0.29%). Congenital infection was detected in 11 infants, giving a transmission rate of 23% overall, 13% in the first trimester, 29% in the second, and 50% in the third. During the 1-year follow-up period only one infant, born to an untreated mother, was found to be clinically affected (unilateral chorioretinitis and loss of vision). At the beginning of pregnancy 0.6% of the previously uninfected women were falsely identified as positive by the Platelia Toxo-IgM test...

Human Recombinant Antibodies against Plasmodium falciparum Merozoite Surface Protein 3 Cloned from Peripheral Blood Leukocytes of Individuals with Immunity to Malaria Demonstrate Antiparasitic Properties

Lundquist, Rasmus; Nielsen, Leif Kofoed; Jafarshad, Ali; SoeSoe, Daw; Christensen, Lars Harder; Druilhe, Pierre; Dziegiel, Morten Hanefeld
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /06/2006 EN
Relevância na Pesquisa
36.69%
Immunoglobulins from individuals with immunity to malaria have a strong antiparasitic effect when transferred to Plasmodium falciparum malaria infected patients. One prominent target of antiparasitic antibodies is the merozoite surface antigen 3 (MSP-3). We have investigated the antibody response against MSP-3 residues 194 to 257 (MSP-3194-257) on the molecular level. mRNA from peripheral blood leukocytes from clinically immune individuals was used as a source of Fab (fragment antibody) genes. A Fab-phage display library was made, and three distinct antibodies designated RAM1, RAM2, and RAM3 were isolated by panning. Immunoglobulin G1 (IgG1) and IgG3 full-length antibodies have been produced in CHO cells. Reactivity with the native parasite protein was demonstrated by immunofluorescence microscopy, flow cytometry, and immunoblotting. Furthermore, the antiparasitic effect of RAM1 has been tested in vitro in an antibody-dependent cellular inhibition (ADCI) assay. Both the IgG1 and the IgG3 versions of the antibody show an inhibitory effect on parasite growth.

CYP4F Enzymes Are the Major Enzymes in Human Liver Microsomes That Catalyze the O-Demethylation of the Antiparasitic Prodrug DB289 [2,5-Bis(4-amidinophenyl)furan-bis-O-methylamidoxime]

Wang, Michael Zhuo; Saulter, Janelle Y.; Usuki, Etsuko; Cheung, Yen-Ling; Hall, Michael; Bridges, Arlene S.; Loewen, Greg; Parkinson, Oliver T.; Stephens, Chad E.; Allen, James L.; Zeldin, Darryl C.; Boykin, David W.; Tidwell, Richard R.; Parkinson, Andre
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
26.25%
DB289 [2,5-bis(4-amidinophenyl)furan-bis-O-methylamidoxime] is biotransformed to the potent antiparasitic diamidine DB75 [2,5-bis(4-amidinophenyl) furan] by sequential oxidative O-demethylation and reductive N-dehydroxylation reactions. Previous work demonstrated that the N-dehydroxylation reactions are catalyzed by cytochrome b5/NADH-cytochrome b5 reductase. Enzymes responsible for catalyzing the DB289 O-demethylation pathway have not been identified. We report an in vitro metabolism study to characterize enzymes in human liver microsomes (HLMs) that catalyze the initial O-demethylation of DB289 (M1 formation). Potent inhibition by 1-aminobenzotriazole confirmed that M1 formation is catalyzed by P450 enzymes. M1 formation by HLMs was NADPH-dependent, with a Km and Vmax of 0.5 μM and 3.8 nmol/min/mg protein, respectively. Initial screening showed that recombinant CYP1A1, CYP1A2, and CYP1B1 were efficient catalysts of M1 formation. However, none of these three enzymes was responsible for M1 formation by HLMs. Further screening showed that recombinant CYP2J2, CYP4F2, and CYP4F3B could also catalyze M1 formation. An antibody against CYP4F2, which inhibited both CYP4F2 and CYP4F3B, inhibited 91% of M1 formation by HLMs. Two inhibitors of P450-mediated arachidonic acid metabolism...

Human Enteric Microsomal CYP4F Enzymes O-Demethylate the Antiparasitic Prodrug Pafuramidine

Wang, Michael Zhuo; Wu, Judy Qiju; Bridges, Arlene S.; Zeldin, Darryl C.; Kornbluth, Sally; Tidwell, Richard R.; Hall, James Edwin; Paine, Mary F.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
26.25%
CYP4F enzymes, including CYP4F2 and CYP4F3B, were recently shown to be the major enzymes catalyzing the initial oxidative O-demethylation of the antiparasitic prodrug pafuramidine (DB289) by human liver microsomes. As suggested by a low oral bioavailability, DB289 could undergo first-pass biotransformation in the intestine, as well as in the liver. Using human intestinal microsomes (HIM), we characterized the enteric enzymes that catalyze the initial O-demethylation of DB289 to the intermediate metabolite, M1. M1 formation in HIM was catalyzed by cytochrome P450 (P450) enzymes, as evidenced by potent inhibition by 1-aminoben-zotriazole and the requirement for NADPH. Apparent Km and Vmax values ranged from 0.6 to 2.4 μM and from 0.02 to 0.89 nmol/min/mg protein, respectively (n = 9). Of the P450 chemical inhibitors evaluated, ketoconazole was the most potent, inhibiting M1 formation by 66%. Two inhibitors of P450-mediated arachidonic acid metabolism, HET0016 (N-hydroxy-N′-(4-n-butyl-2-methylphenyl)formamidine) and 17-octadecynoic acid, inhibited M1 formation in a concentration-dependent manner (up to 95%). Immunoinhibition with an antibody raised against CYP4F2 showed concentration-dependent inhibition of M1 formation (up to 92%)...

Recombinant Viral Vaccines Expressing Merozoite Surface Protein-1 Induce Antibody- and T Cell-Mediated Multistage Protection against Malaria

Draper, Simon J.; Goodman, Anna L.; Biswas, Sumi; Forbes, Emily K.; Moore, Anne C.; Gilbert, Sarah C.; Hill, Adrian V.S.
Fonte: Cell Press Publicador: Cell Press
Tipo: Artigo de Revista Científica
Publicado em 22/01/2009 EN
Relevância na Pesquisa
16%
Protecting against both liver and blood stages of infection is a long-sought goal of malaria vaccine design. Recently, we described the use of replication-defective viral vaccine vectors expressing the malaria antigen merozoite surface protein-1 (MSP-1) as an antimalarial vaccine strategy that elicits potent and protective antibody responses against blood-stage parasites. Here, we show that vaccine-induced MSP-1-specific CD4+ T cells provide essential help for protective B cell responses, and CD8+ T cells mediate significant antiparasitic activity against liver-stage parasites. Enhanced survival is subsequently seen in immunized mice following challenge with sporozoites, which mimics the natural route of infection more closely than when using infected red blood cells. This effect is evident both in the presence and absence of protective antibodies and is associated with decreased parasite burden in the liver followed by enhanced induction of the cytokine IFN-γ in the serum. Multistage immunity against malaria can thus be achieved by using viral vectors recombinant for MSP-1.

Plasmodium falciparum Merozoite Surface Protein 1 (MSP-1)-MSP-3 Chimeric Protein: Immunogenicity Determined with Human-Compatible Adjuvants and Induction of Protective Immune Response▿ †

Mazumdar, Suman; Mukherjee, Paushali; Yazdani, Syed Shams; Jain, S. K.; Mohmmed, Asif; Chauhan, Virander Singh
Fonte: American Society for Microbiology (ASM) Publicador: American Society for Microbiology (ASM)
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
16.66%
A chimeric gene, MSP-Fu24, was constructed by genetically coupling immunodominant, conserved regions of the two leading malaria vaccine candidates, Plasmodium falciparum merozoite surface protein 1 (C-terminal 19-kDa region [PfMSP-119]) and merozoite surface protein 3 (11-kDa conserved region [PfMSP-311]). The recombinant MSP-Fu24 protein was produced in Escherichia coli cells and purified to homogeneity by a two-step purification process with a yield of ∼30 mg/liter. Analyses of conformational properties of MSP-Fu24 using PfMSP-119-specific monoclonal antibody showed that the conformational epitopes of PfMSP-119 that may be critical for the generation of the antiparasitic immune response remained intact in the fusion protein. Recombinant MSP-Fu24 was highly immunogenic in mice and in rabbits when formulated with two different human-compatible adjuvants and induced an immune response against both PfMSP-119 and PfMSP-311. Purified anti-MSP-Fu24 antibodies showed invasion inhibition of P. falciparum 3D7 and FCR parasites, and this effect was found to be dependent on antibodies specific for the PfMSP-119 component. The protective potential of MSP-Fu24 was demonstrated by in vitro parasite growth inhibition using an antibody-dependent cell inhibition (ADCI) assay with anti-MSP-Fu24 antibodies. Overall...

Clinical Features of Ocular Toxoplasmosis in Korean Patients

Park, Young-Hoon; Han, Jae-Hyung; Nam, Ho-Woo
Fonte: The Korean Society for Parasitology Publicador: The Korean Society for Parasitology
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
16%
We report here the records of 10 consecutive Korean patients (10 eyes) with ocular toxoplasmosis which showed the typical clinical manifestations with seropositivity for Toxoplasma gondii specific IgG antibodies by micro-ELISA between 2006 and 2010. Nine patients were males and 1 was female; their age was 50.5±13.8 years. The most common accompanying signs were vitritis (100%), anterior uveitis (70%), and scattered white deposit (80%). Pre-existing retinochoroidal scar was found in 1 (10%) patient. All patients received antiparasitic chemotherapy and systemic corticosteroid treatment, which resolved the presenting attack and recovered the visual acuity better than initial one in 9 patients and worse in 1. Optic atrophy, cataract, and retinal neovascularization were observed during the follow-up period and recurrence was detected in 3 eyes (30%) 6 to 20 months after the initial attack. In Korea, although rarely detected and reported, ocular toxoplasmosis needs more attention in clinical field of retinal diseases.

Analysis of the course and treatment of toxocariasis in children—a long-term observation

Wiśniewska-Ligier, M.; Woźniakowska-Gęsicka, T.; Sobolewska-Dryjańska, J.; Markiewicz-Jóźwiak, A.; Wieczorek, M.
Fonte: Springer-Verlag Publicador: Springer-Verlag
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
16.44%
Toxocariasis is a helminthozoonotic disease caused by ascarid larvae of Toxocara genus: Toxocara canis and Toxocara cati. In the reported study, the clinical course of toxocariasis and administered therapy were evaluated in 103 children. The majority of the children (68.9%) were from the rural environment, with a prevalence of boys (62.1%). At diagnosis of infection, 36 (35%) children reported recurrent abdominal pain, 19 (18.4%) headache, 6 (5.8%) loss of appetite, 2 subfebrile conditions, and 2 arthralgia, Moreover, 23 (22.3%) children demonstrated symptoms of atopic diseases; in 30 (29.1%) children, moderate enlargement of lymphatic nodes was noted. In five children (4.9%), ophthalmic examination revealed unilateral changes in the eye: in two cases retinitis; in one case fibrotic lesions in the vitreous body, complicated 1 year from diagnosis by retinal detachment; and in other children parafoveal lesions and cataract. Only two children with ocular changes at diagnosis reported visual disorders. In 64.3% of children, eosinophilia was observed. A covert form of the disease was diagnosed in 95.1% of the children and an ocular form in 4.9%. In all the children, antiparasitic treatment was implemented, repeated several times in some of them. After therapy...

Antiparasitic treatment suppresses production and avidity of Toxoplasma gondii-specific antibodies in a murine model of acute infection*

Alvarado-Esquivel, C.; Niewiadomski, A.; Schweickert, B.; Liesenfeld, O.
Fonte: Akadémiai Kiadó Publicador: Akadémiai Kiadó
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
26.75%
Infection with Toxoplasma gondii during pregnancy may result in congenital transmission of the parasite. Infection is commonly diagnosed using serological tests for IgG, IgM and IgA antibodies. Avidity of IgG antibodies is used to exclude acute infection. Few studies have investigated the impact of antiparasitic treatment on the production of anti-T. gondii antibody and the avidity of IgG antibodies. We therefore investigated the production of IgG, IgM, and IgA antibodies and IgG avidity in a murine model of acute infection with 10 cysts of T. gondii. All antibody classes increased following infection. Treatment of mice with pyrimethamine/​sulfadiazine but not with spiramycin or azithromycin at dosages equivalent to those used in patients resulted in a significant decrease in the concentration of T. gondii-specific IgG and IgM antibodies postinfection. IgG and IgM antibody decreases were paralleled by a significant reduction in cyst numbers in brains of mice treated with pyrimethamine/sulfadiazine but not with other drugs. In contrast, treatment with atovaquone did significantly reduce the concentrations of IgM antibodies and resulted in reduced IgG avidity indices. T. gondii-specific DNA was not detected in blood between days 1 and 3. In conclusion...

Antibodies to an Epitope from the Cha Human Autoantigen Are Markers of Chagas' Disease

Gironès, Núria; Rodríguez, Clara I.; Basso, Beatriz; Bellon, José M.; Resino, Salvador; Muñoz-Fernández, M. Angeles; Gea, Susana; Moretti, Edgardo; Fresno, Manuel
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /11/2001 EN
Relevância na Pesquisa
26.26%
Chagas' disease is a prevalent disease in South America that is thought to have an autoimmune etiology. We previously identified human Cha as a new autoantigen recognized by chagasic sera. Those sera recognized an epitope spanning amino acids 120 to 129 of Cha, named R3. In the present study we have used the synthetic R3 peptide for the detection of serum immunoglobulin G antibodies from patients at different stages of Chagas' disease, including a therapeutically treated group. The immunoreactivity with R3 by enzyme-linked immunosorbent assay (ELISA) showed 92.4% sensitivity and 100% specificity for Chagas' disease sera. This sensitivity and specificity were higher than for any other autoantigen described to date. No anti-R3 antibodies were detected in sera from Leishmania-infected or idiopathic dilated cardiomyopathy patients or healthy controls from the same areas. Moreover, anti-R3 antibody reactivity detected by ELISA correlated with conventional serological tests as indirect immunofluorescence and ELISA assays with Trypanosoma cruzi extracts and other diagnostic tests as indirect hemagglutination. The levels of anti-R3 antibodies increased with progression and symptomatology of Chagas' disease. More interestingly, a statistically significant fall in anti-R3 antibody titer was observed in patients treated with antiparasitic drugs. Those results suggest that the presence of anti-R3 antibodies is a highly specific marker of Chagas' disease and that R3 ELISA could be helpful in the diagnosis and monitoring of this disease.

NK Cells Contribute to the Control of Trypanosoma cruzi Infection by Killing Free Parasites by Perforin-Independent Mechanisms

Lieke, Thorsten; Graefe, Sebastian E. B.; Klauenberg, Ulricke; Fleischer, Bernhard; Jacobs, Thomas
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /12/2004 EN
Relevância na Pesquisa
16%
The protozoan parasite Trypanosoma cruzi circulates in the blood as trypomastigotes and invades a variety of cells to multiply intracellularly as amastigotes. The acute phase leads to an immune response that restricts the proliferation of the parasite. However, parasites are able to persist in different tissues, which causes the pathology of Chagas' disease. Natural killer (NK) cells play an important role in innate resistance to a variety of pathogens. In the present study we analyzed whether NK cells participated in the control of experimental T. cruzi infection. NK cells were depleted from C57BL/6 mice by antiasialo antibodies. This treatment caused an increased parasitemia during the acute phase, but tissue parasite burdens were not significantly altered according to quantitative real-time PCR. Our results demonstrated that NK cells were activated during the initial phase of a T. cruzi infection and exhibited a contact-dependent antiparasitic activity against extracellular parasites that was independent from perforin. Thus, NK cells limit the propagation of the parasite by acting on circulating T. cruzi trypomastigotes.

Transcutaneous Immunization Using Colonization Factor and Heat-Labile Enterotoxin Induces Correlates of Protective Immunity for Enterotoxigenic Escherichia coli

Yu, Jianmei; Cassels, Frederick; Scharton-Kersten, Tanya; Hammond, Scott A.; Hartman, Antoinette; Angov, Evelina; Corthésy, Blaise; Alving, Carl; Glenn, Gregory
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /03/2002 EN
Relevância na Pesquisa
16%
Enterotoxigenic Escherichia coli (ETEC) diarrheal disease is a worldwide problem that may be addressed by transcutaneous delivery of a vaccine. In several human settings, protective immunity has been associated with immune responses to E. coli colonization factors and to the heat-labile toxin that induces the diarrhea. In this set of animal studies, transcutaneous immunization (TCI) using recombinant colonization factor CS6 and cholera toxin (CT) or heat-labile enterotoxin (LT) as the adjuvant induced immunoglobulin G (IgG) and IgA anti-CS6 responses in sera and stools and antibody responses that recognized CS6 antigen in its native configuration. The antitoxin immunity induced by TCI was also shown to protect against enteric toxin challenge. Although immunization with LT via the skin induced mucosal secretory IgA responses to LT, protection could also be achieved by intravenous injection of the immune sera. Finally, a malaria vaccine antigen, merzoite surface protein 142 administered with CT as the adjuvant, induced both merzoite surface protein antibodies and T-cell responses while conferring protective antitoxin immunity, suggesting that both antiparasitic activity and antidiarrheal activity can be obtained with a single vaccine formulation. Overall...

Malaria parasite specific TH1-like cells simultaneously reduce parasitaemia and promote disease

Hirunpetcharat, Chakrit; Finkelman, Fred; Clark, Ian A; Good, Michael
Fonte: Blackwell Publishing Ltd Publicador: Blackwell Publishing Ltd
Tipo: Artigo de Revista Científica
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CD4+ T cells have been implicated in immunity to the blood stages of malaria and cytokines associated with both monocyte and T cell activation have been implicated in disease. To determine whether specific T cells capable of inhibiting parasite growth can also mediate pathology we have transfused populations of Plasmodium berghei-specific T cells into normal and immunodeficient naive mice. We observed that they could inhibit parasite growth but were unable to save the animals which exhibited significantly greater anaemia and weight loss than control infected animals receiving either no T cells or T cells specific for ovalbumin. T cell-dependent tomour necrosis factor (TNF)α was a critical component in both parasite killing and disease promotion. Experiments with blocking antibodies demonstrated that all T-cell mediated antiparasitic immunity and all T-cell mediated weight loss was TNF-dependent. Blocking TNF-α in mice that received parasite-specific T cells prolonged the survival of the mice. Nitic oxide demonstrated no antiparasite effect, but was involved in the regulation of T-cell mediated weight loss. The data thus show that while parasite-specific CD4+ T cells can significantly limit parasite growth, such an effect need not be beneficial to the host...