A Novel Polyclonal Antiserum against Toxoplasma gondii Sodium Hydrogen Exchanger 1

The sodium hydrogen exchanger 1 (NHE1), which functions in maintaining the ratio of Na+ and H+ ions, is widely distributed in cell plasma membranes. It plays a prominent role in pH balancing, cell proliferation, differentiation, adhesion, and migration. However, its exact subcellular location and biological functions in Toxoplasma gondii are largely unclear. In this study, we cloned the C-terminal sequence of T. gondii NHE1 (TgNHE1) incorporating the C-terminal peptide of NHE1 (C-NHE1) into the pGEX4T-1 expression plasmid. The peptide sequence was predicted to have good antigenicity based on the information obtained from an immune epitope database. After induction of heterologous gene expression with isopropyl-b-D-thiogalactoside, the recombinant C-NHE1 protein successfully expressed in a soluble form was purified by glutathione sepharose beads as an immunogen for production of a rabbit polyclonal antiserum. The specificity of this antiserum was confirmed by western blotting and immunofluorescence. The antiserum could reduce T. gondii invasion into host cells, indicated by the decreased TgNHE1 expression in T. gondii parasites that were pre-incubated with antiserum in the process of cell entry. Furthermore, the antiserum reduced the virulence of T. gondii parasites to host cells in vitro, possibly by blocking the release of Ca2+. In this regard, this antiserum has potential to be a valuable tool for further studies of TgNHE1.

Sequence Diversity in MIC6 Gene among Toxoplasma gondii Isolates from Different Hosts and Geographical Locations

Toxoplasma gondii is an opportunistic protozoan parasite that can infect almost all warm-blooded animals including humans with a worldwide distribution. Micronemes play an important role in invasion process of T. gondii, associated with the attachment, motility, and host cell recognition. In this research, sequence diversity in microneme protein 6 (MIC6) gene among 16 T. gondii isolates from different hosts and geographical regions and 1 reference strain was examined. The results showed that the sequence of all the examined T. gondii strains was 1,050 bp in length, and their A + T content was between 45.7% and 46.1%. Sequence analysis presented 33 nucleotide mutation positions (0-1.1%), resulting in 23 amino acid substitutions (0-2.3%) aligned with T. gondii RH strain. Moreover, T. gondii strains representing the 3 classical genotypes (Type I, II, and III) were separated into different clusters based on the locus of MIC6 using phylogenetic analyses by Bayesian inference (BI), maximum parsimony (MP), and maximum likelihood (ML), but T. gondii strains belonging to ToxoDB #9 were separated into different clusters. Our results suggested that MIC6 gene is not a suitable marker for T. gondii population genetic studies.

Genetic Diversity of Toxoplasma gondii Strains from Different Hosts and Geographical Regions by Sequence Analysis of GRA20 Gene

Toxoplasma gondii is a eukaryotic parasite of the phylum Apicomplexa, which infects all warm-blood animals, including humans. In the present study, we examined sequence variation in dense granule 20 (GRA20) genes among T. gondii isolates collected from different hosts and geographical regions worldwide. The complete GRA20 genes were amplified from 16 T. gondii isolates using PCR, sequence were analyzed, and phylogenetic reconstruction was analyzed by maximum parsimony (MP) and maximum likelihood (ML) methods. The results showed that the complete GRA20 gene sequence was 1,586 bp in length among all the isolates used in this study, and the sequence variations in nucleotides were 0-7.9% among all strains. However, removing the type III strains (CTG, VEG), the sequence variations became very low, only 0-0.7%. These results indicated that the GRA20 sequence in type III was more divergence. Phylogenetic analysis of GRA20 sequences using MP and ML methods can differentiate 2 major clonal lineage types (type I and type III) into their respective clusters, indicating the GRA20 gene may represent a novel genetic marker for intraspecific phylogenetic analyses of T. gondii.

Sequence Variation in Superoxide Dismutase Gene of Toxoplasma gondii among Various Isolates from Different Hosts and Geographical Regions

Toxoplasma gondii, an obligate intracellular protozoan parasite of the phylum Apicomplexa, can infect all warm-blooded vertebrates, including humans, livestock, and marine mammals. The aim of this study was to investigate whether superoxide dismutase (SOD) of T. gondii can be used as a new marker for genetic study or a potential vaccine candidate. The partial genome region of the SOD gene was amplified and sequenced from 10 different T. gondii isolates from different parts of the world, and all the sequences were examined by PCR-RFLP, sequence analysis, and phylogenetic reconstruction. The results showed that partial SOD gene sequences ranged from 1,702 bp to 1,712 bp and A + T contents varied from 50.1% to 51.1% among all examined isolates. Sequence alignment analysis identified total 43 variable nucleotide positions, and these results showed that 97.5% sequence similarity of SOD gene among all examined isolates. Phylogenetic analysis revealed that these SOD sequences were not an effective molecular marker for differential identification of T. gondii strains. The research demonstrated existence of low sequence variation in the SOD gene among T. gondii strains of different genotypes from different hosts and geographical regions.

BEHAVIORAL AND MEMORY CHANGES IN Mus musculus COINFECTED BY Toxocara canis AND Toxoplasma gondii / Alterações comportamentais e na memória de Mus musculus coinfectado por Toxocara canis e Toxoplasma gondii

Several researchers have stated that parasites can alter the behavior of their hosts, in order to increase the transmission rate, principally when prey-predator relationships are a reliable way of infection transmission. The aim of this study was to verify the occurrence of changes in anxiety and short-term memory patterns in experimentally infected Mus musculus by Toxocara canis and/or Toxoplasma gondii. Forty male Mus musculus (Balb/c) eight-week-old were divided into four groups of 10 mice each. One group was infected with 300 eggs of Toxocara canis; a second group was submitted to infection with 10 cysts of Toxoplasma gondii; a third group was concomitantly infected with both parasites with the same inoculums and the last group was maintained without infection. The anxiety levels were evaluated using an elevated plus maze and an actometer; the short-term memory was determined by a two-way active avoidance equipment. The determination of anxiety levels were conducted 40 and 70 days after infection and the short-term memory was evaluated 140 days after infection. Mice chronically infected by Toxoplasma gondii showed impaired learning and short-term memory, but no significant differences were found in mice infected by Toxocara canis or concomitantly infected by Toxocara canis and Toxoplasma gondii when compared to non infected mice.

Pesquisadores afirmam que parasitos podem alterar o comportamento de seus hospedeiros a fim de aumentar a sua taxa de transmissão. O objetivo deste estudo foi verificar a ocorrência de alterações na ansiedade e padrões de memória de curta duração em Mus musculus experimentalmente infectados por Toxocara canis e/ou Toxoplasma gondii. Utilizaram-se 40 camundongos da espécie Mus musculus machos (Balb/c) com oito semanas de idade, divididos em quatro grupos de 10 ratos cada. Um grupo foi infectado com 300 ovos de Toxocara canis, um segundo grupo foi submetido à infecção com 10 cistos de T. gondii, um terceiro grupo foi infectado concomitantemente com ambos os parasitas e o último grupo foi mantido sem infecção. Os níveis de ansiedade foram avaliados por meio de labirinto em cruz elevado e actômetro, a memória de curta duração foi determinada por esquiva aversiva. A determinação dos níveis de ansiedade foi realizada 40 e 70 dias após infecção e a memória de curto prazo foi avaliada 140 dias após a infecção. Camundongos cronicamente infectados por Toxoplasma gondii mostraram deficiência de aprendizagem e memória de curto prazo, mas não foram encontradas diferenças significantes em camundongos infectados por Toxocara canis ou concomitantemente infectados por Toxocara canis e Toxoplasma gondii quando comparados com camundongos não infectados.

Estudio retrospectivo de la aplicación de la amplificación génica cualitativa en muestras biológicas para el seguimiento de la toxoplasmosis en pacientes pediátricos receptores de trasplante de células progenitoras hematopoyéticas / Retrospective study of the implementation of the qualitative PCR technique in biological samples for monitoring toxoplasmosis in pediatric patients receiving hematopoietic stem cell transplantion

La toxoplasmosis es una infección oportunista causada por el parásito Toxoplasma gondii; su infección es grave y de difícil diagnóstico en pacientes que reciben un trasplante alogénico de células progenitoras hematopoyéticas (TCPH). En el Hospital de Pediatría S.A.M.I.C. "Profesor Dr. Juan P. Garrahan" se realizó la vigilancia postrasplante de 12 pacientes receptores de TCPH mediante la técnica de PCR cualitativa. La necesidad de seguimiento de estos pacientes fue definida por el antecedente de serología positiva para toxoplasmosis en el donante o receptor y ante la imposibilidad de iniciar el uso profiláctico de trimetoprima-sulfametoxazol a causa de la condición hematológica. Dos pacientes presentaron signos de enfermedad por T. gondii con resultado de PCR positivo y recibieron tratamiento con pirimetamina-clindamicina. En otros dos, la toxoplasmosis fue causa de muerte y hallazgo de autopsia, con resultado de PCR negativo. Cuatro pacientes recibieron tratamiento contra toxoplasmosis por la detección de una PCR positiva, sin manifestaciones clínicas. En los cuatro pacientes restantes no se detectaron signos de enfermedad por toxoplasmosis, con resultados de PCR negativos durante el seguimiento. La técnica de PCR cualitativa demostró ser útil para detectar la reactivación de la toxoplasmosis en receptores de TCPH, pero tiene limitaciones para el seguimiento y la toma de decisiones clínicas en pacientes con PCR positiva que persiste en el tiempo y manifestaciones de toxicidad por el tratamiento.

Toxoplasmosis is an opportunistic infection caused by the parasite Toxoplasma gondii. The infection is severe and difficult to diagnose in patients receiving allogeneic hematopoietic stem cell transplantation (HSCT). Twelve patients receiving HSCT were monitored post-transplant, by qualitative PCR at the Children's Hospital S.A.M.I.C. "Prof. Dr. Juan P. Garrahan". The monitoring of these patients was defined by a history of positive serology for toxoplasmosis in the donor or recipient and because their hematologic condition did not allow the use of trimethoprim-sulfamethoxazole for prophylaxis. During the patients' monitoring, two of them with positive PCR results showed signs of illness by T. gondii and were treated with pyrimethamine-clindamycin. In two other patients, toxoplasmosis was the cause of death and an autopsy finding, showing negative PCR results. Four patients without clinical manifestations received treatment for toxoplasmosis because of positive PCR detection. In four patients there were no signs of toxoplasmosis disease and negative PCR results during follow-up. The qualitative PCR technique proved useful for the detection of toxoplasmosis reactivation in HSCT recipients, but has limitations in monitoring and making clinical decisions due to the persistence of positive PCR over time and manifestations of toxicity caused by the treatment.

Toxoplasmose gástrica em paciente infectado pelo vírus da imunodeficiência humana. Relato de caso / Gastric toxoplasmosis in patient infected with human immunodeficiency virus. Case report

A toxoplasmose é uma zoonose altamente disseminada. A maio­ria das infecções em imunocompetentes é assintomática. Porém, em pacientes imunodeprimidos, a infecção adquire um curso variável. Em pacientes com contagem de CD4 abaixo de 100 e que foram previamente expostos ao Toxoplasma gondii, pode haver reativação da doença em diversos tecidos. Envolvimento do trato gastrintestinal por Toxoplasma gondii é raramente relatado. Embora os sintomas gastrintestinais sejam comuns entre os pacientes com síndrome da imunodeficiência adquirida, a maioria é causada por infecções entéricas que não o Toxoplasma gondii. O objetivo deste estudo foi relatar um caso raro de toxoplasmose gástrica. Paciente do gênero feminino, 38 anos, com diagnóstico recente de vírus da imunodeficiência humana, iniciou sintomas gástricos inespecíficos como: epigastralgia, náuseas, vômitos e perda ponderal. O diagnóstico definitivo foi fechado com o estudo anatomopatológico da lesão na mucosa gástrica. Foi instituído tratamento para a toxoplasmose com clindamicina, pirimetamina e ácido folínico (devido à mielotoxicidade), com melhora parcial dos sintomas. Embora raro, a toxoplasmose gástrica deve entrar no diagnóstico diferencial de dor epigástrica em pacientes portadores da síndrome da imunodeficiência adquirida com contagem de CD4 baixa. Seu diagnóstico pre­suntivo pode ser dado pelo quadro clínico, mas o diagnóstico definitivo é obtido pela biópsia da lesão...

Toxoplasmosis is a highly disseminated zoonosis. Most infections are asymptomatic in immunocompetent patients. However, in immunocompromised patients, infection acquires a variable course. In patients with CD4 counts lower than 100 and who have been previously exposed to Toxoplasma gondii, there may be reactivation of the disease in various tissues. Involvement of the gastrointestinal tract by Toxoplasma gondii is rarely reported. Although gastrointestinal symptoms are common among patients with acquired immunodeficiency syndrome, most are caused by enteric infections other than Toxoplasma gondii. The aim of this study was to report a rare case of gastric toxoplasmosis. A 38-year-­old female patient, recently diagnosed with immunodeficiency human virus, presented with nonspecific gastric symptoms such as epigastric pain, nausea, vomiting and weight loss. The definitive diagnosis was reached with anatomopathological examination of gastric mucosa damage. She was treated for toxoplasmosis with clindamycin, pyrimethamine and folinic acid (due to myelotoxicity), with partial improvement of symptoms. Although rare, gastric toxoplasmosis should enter the differential diagnosis of epigastric pain in patients with acquired immunodeficiency syndrome with low CD4 count. Its presumptive diagnosis can be made on a clinical basis, but the definitive diagnosis is reached with biopsy...

Revista Brasileira de Parasitologia Vet / Brazilian Journal of Veterinary Parasitology

Cistos cerebrais parasitários

Cistos cerebrais parasitários constituem um grande problema para o gado. Entre estes, coenurosis e toxoplasmose são predominantes. Aqui, um número total de 60 ovelhas obtidas em uma fazenda particular na província Suez, Egito, foram examinadas post-mortem para a detecção de cistos parasitários visíveis e microscopicamente para detectar cistos de pequenas dimensões. A necropsia revelou cistos medindo entre 0,5-6,5 cm de diâmetro, preenchidos com o fluido transparente, contendo um grande número de protoscolices. Por conseguinte, os cistos foram identificados como metacestóide Coenurus cerebralis. Entre as ovelhas examinadas, 11 animais (7 machos e 4 fêmeas) (18,3%) estavam infectados. A maior parte dos cistosestavam localizados nos hemisférios cerebrais, com números variando de um a três em ovinos infectados. O efeito da presença de cistos no tecido do cérebro foi avaliado. Histopatologicamente, pseudoscistos de Toxoplasma gondii foram encontrados em dois animais sem reações inflamatórias detectáveis. Em conclusão, coenurosis e toxoplasmose são graves problemas parasitários que desempenham um papel significativo no manejo de ovelhas no Egito, como resultado do contacto íntimo dos animais com os cães e gatos, que desempenham um papel crítico no ciclo de vida desses parasitas

Parasitosis intestinales y tisulares y su relación con la eosinofilia en una comunidad indígena Yukpa de la Sierra de Perijá, estado Zulia / Intestinal and tissue parasites and their relation with eosinophilia in a Yukpa Amerindian community from the Mountains of Perijá, state of Zulia

Para determinar la prevalencia de parasitosis intestinales y tisulares y su relación con la eosinofilia en una comunidad indígena Yukpa, se analizaron 91 muestras fecales y sanguíneas. A las muestras fecales se les practicó examen coproscópico y concentrado. Se realizó hematología completa para determinar cuenta blanca y porcentaje de eosinófilos, y en suero se efectuó un test de ELISA para la detección de anticuerpos anti- Toxocara canis y anti- Toxoplasma gondii. Se observó una elevada prevalencia de parasitosis intestinales (90,10%). Se apreció predominio de protozoarios sobre helmintos, siendo para los primeros el más prevalente Blastocystis sp. (51,64%) y para los segundos Ascaris lumbricoides (38,46%). La seroprevalencia de anticuerpos anti-Toxocara canis fue de 24,17% y anti-Toxoplasma gondii de 43.95%. No se observó diferencias estadísticamente significativas entre los grupos de edad y sexo en las diferentes parasitosis intestinales y tisulares. No se encontró asociación entre la seroprevalencia para Toxocara canis y la eosinofilia. Se apreció una asociación estadística significativa entre la presencia de eosinofilia y las helmintiasis. Estos resultados sugieren que existe una alta prevalencia de infecciones parasitarias en estas comunidades debido probablemente a sus costumbres y las condiciones sanitarias en las que habitan.

To determine the prevalence of intestinal and tissue parasites and their relationship with eosinophilia in Yukpa Amerindians, 91 fecal and blood samples were analyzed. The fecal samples underwent microscopic and concentrated examinations. Complete hematology was performed to determine white count and percentage of eosinophils; and ELISA tests were performed on the serum to detect anti-Toxocara canis and anti-Toxoplasma gondii antibodies. A high prevalence of intestinal parasites (90.10%) was observed. The predominance of protozoa over helminths was noted; for the first, the most prevalent were Blastocystis hominis (51.64%), and for the second, Ascaris lumbricoides (38.46%). Seroprevalence of anti-Toxocara canis antibodies was 24.17% and for anti-Toxoplasma gondi, 43.95%. No statistically significant differences were observed between age and sex groups for the different intestinal and tissue parasites. No association between seroprevalence for Toxocara canis and eosinophilia was found. A statistically significant association between the presence of eosinophilia and helminthiasis was observed. These results suggest that there is a high prevalence of parasitic infections in these communities due probably to their customs and the sanitary conditions in which they live.

Profilaxis de toxoplasmosis en niños y adultos sometidos a trasplante de órganos sólidos y precursores hematopoyéticos / Prophylaxis against Toxoplasma gondii disease in pediatric and adult patients undergoing solid organ and hematopoietic stem cells transplantation

Toxoplasmosis is a widely distributed zoonosis produced by the parasite T. gondii. In Chile the seroprevalence has been estimated between 20-37% in general population. Defined risk groups acquire or reactivate the infection by T. gondii in patients undergoing SOT and HSCT are: heart transplant or heart-lung with D (+) and R (-), allogeneic HSCT with R (+), HSCT with cord cells, GVHD, history of previous clinical toxoplasmosis and use of corticosteroids for prolonged periods or in high doses. Hand washing, hygiene in food handling and weekly post-transplant surveillance since day 15 post transplant for six months, are universally recommended. All patients with SOT and HSCT, regardless of risk, should receive prophylaxis with cotrimoxazole and require no another specific prophylaxis against T. gondii (A2). It is particularly important in high-risk patients who cannot receive cotrimoxazole prophylaxis establish specific alternative against T. gondii (B3).

Toxoplasmosis es una zoonosis ampliamente distribuida, producida por el parásito T. gondii. En Chile la seroprevalencia se ha estimado entre 20-37% en la población general. Se han deinido grupos de riesgo de adquirir o reactivar la infección por T. gondii en pacientes sometidos a TOS y a TPH: trasplante cardíaco o de corazón-pulmón con D (+) y R (-); TPH alogénico con R (+); TPH con células de cordón; EICH activa; antecedentes de toxoplasmosis clínica previa y uso de corticoesteroides por tiempo prolongado o en altas dosis. De manera universal son importantes el lavado de manos e higiene en manipulación de alimentos y el seguimiento periódico post-trasplante con RPC desde los 15 días, una vez por semana, durante seis meses. Todos los pacientes con TOS y TPH, independiente de su riesgo, deben recibir proilaxis universal con cotrimoxazol y no requieren otra proilaxis especíica contra T. gondii ( A2 ). Es particularmente importante que en los pacientes de alto riesgo que no puedan recibir cotrimoxazol, se establezca proilaxis alternativa especíica contra T. gondii (B3).

Modelo para la dinámica de transmisión de la toxoplasmosis congénita / A model of congenital toxoplasmosis transmission dynamics

La toxoplasmosis es una zoonosis parasitaria de amplia distribución mundial, que infecta una gran proporción de poblaciones humanas y animales, producida por el parásito Toxoplasma gondii, siendo de gran importancia el contagio de mujeres gestantes, puesto que ésta zoonosis causa enfermedades en los fetos a través de infección transplacentaria; tradicionalmente se ha utilizado una tasa de infección madre-feto constante; sin embargo, hay evidencias de una fuerte relación con la semana de gestación de la madre en el momento de contagiar al feto. Este trabajo describe la dinámica de transmisión de la toxoplasmosis congénita a través de un modelo estructurado en la edad que tiene en cuenta la semana de gestación de la madre; el modelo está acoplado con un modelo espacio-temporal que describe la dispersión de T. gondii a través de gatos, el cual proporciona la cantidad de parásitos en el ambiente, de la cual depende que una mujer gestante se infecte. Se hacen simulaciones variando la cantidad de parásitos y la distancia a la que se encuentra la gestante del lugar del inóculo; además, se varían algunos parámetros equivalentes a posibles medidas de control. Se encuentran cambios importantes al comparar el comportamiento de las poblaciones de gestantes infectadas, cuando se usa tasa de infección madrefeto constante y cuando se usa tasa dependiente de la semana de gestación, lo que permite concluir que la semana de gestación en la que se encuentra la población de gestantes infectadas es fundamental en la transmisión de la infección al feto.

Toxoplasmosis is a parasitic zoonosis having worldwide distribution; it infects many human and animal populations and is produced by the parasite Toxoplasma gondii, this being of great importance in contagion of pregnant women since this zoonosis causes illness in the fetus through transplacental infection. A constant mother-foetus infection rate has traditionally been used. Nevertheless, there is evidence of a strong relationship between a mother's gestation week and the moment when a foetus becomes infected. This work describes congenital toxoplasmosis transmission dynamics by using an age-structured model taking a mother's gestational week into account. The model was adapted to a space-time model describing T. gondii dispersion through cats; this provided the amount of parasites in the environment depending on which a pregnant woman would become infected. Simulations were done, varying the amount of parasites and the pregnant mother-inoculum distance. Some parameters related to possible control measures were also varied. Important changes were found when comparing infected pregnant female population patterns, when a constant mother-fetus infection rate was used and when a dependent pregnancy week rate was used. This led to concluding that the gestation week in which the mothers became infected is fundamental in infection being transmitted to their fetuses.

Proteomic Analysis of Toxoplasma gondii KI-1 Tachyzoites

We studied on the proteomic characteristics of Toxoplasma gondii KI-1 tachyzoites which were originally isolated from a Korean patient, and compared with those of the well-known virulent RH strain using 2-dimensional electrophoresis (2-DE), mass spectrometry, and quantitative real-time PCR. Two-dimensional separation of the total proteins isolated from KI-1 tachyzoites revealed up to 150 spots, of which 121 were consistent with those of RH tachyzoites. Of the remaining 29 spots, 14 showed greater than 5-fold difference in density between the KI-1 and RH tachyzoites at a pH of 5.0-8.0. Among the 14 spots, 5 from the KI-1 isolate and 7 from the RH strain were identified using MALDI-TOF mass spectrometry and database searches. The spots from the KI-1 tachyzoites were dense granule proteins (GRA 2, 3, 6, and 7), hypoxanthine-guanine-xanthine phosphoribosyltransferase (HGRPTase), and uracil phosphoribosyltransferase (UPRTase). The spots from the RH strain were surface antigen 1 (SAG 1), L-lactate dehydrogenase (LDH), actin, chorismate synthase, peroximal catalase, hexokinase, bifunctional dihydrofolate reductase-thymidylate synthase (DHTR-TS), and nucleoside-triphosphatases (NTPases). Quantitative real-time PCR supported our mass spectrometric results by showing the elevated expression of the genes encoding GRA 2, 3, and 6 and UPRTase in the KI-1 tachyzoites and those encoding GRA 7, SAG 1, NTPase, and chorismate synthase in the RH tachyzoites. These observations demonstrate that the protein compositions of KI-1 and RH tachyzoites are similar but differential protein expression is involved in virulence.

Toxoplasma gondii: 1908-2008, homage to Nicolle, Manceaux and Splendore

The discovery of Toxoplasma gondii independently by Nicolle and Manceaux (1908) and Splendore (1908) was to open a "Pandora's Box" that has led research on this parasite into a number of scientific disciplines. In the 100 years since its discovery, the mystery surrounding T. gondii and its inter-relationship with humans has continued to provide a stimulating source of material in many areas of research, resulting in the publication of almost 20,000 papers and a number of books. This flood of diverse information shows no sign of abating, with an average of 10 papers per week appearing in PubMed. Herein, it is impossible to do more than provide a very superficial comment on what has become a massive body of scientific information. T. gondii has many unique features and seems to be the "exception to almost every rule" thus acting as a focus for research in disciplines from epidemiology to immunology to human behaviour to cell biology to human disease. In this review a number of the historical advances will be mentioned and combined with a description of the basic biology of the parasite.

Toxoplasma gondii infection induces lipid metabolism alterations in the murine host

Host lipids have been implicated in the pathogenesis of Toxoplasma gondiiinfection. To determine if Toxoplasmainfection influences the lipid status in the normal host, we assessed serum lipids of Swiss-Webster mice during infection with the BGD-1 strain (type-2) at a series of time points. Mice were bled at days zero and 42 post-infection, and subgroups were additionally bled on alternating weeks (model 1), or sacrificed at days zero, 14 and 42 (model 2) for the measurement of total cholesterol (Chl), high density lipoproteins (HDL), low density lipoproteins (LDL) and triglycerides and adiponectin. At day 42, brains were harvested for cyst enumeration. A significant decrease (p = 0.02) in HDL and total Chl was first noted in infected vs. control mice at day 14 and persisted to day 42 (p = 0.013). Conversely, LDL was unaltered until day 42, when it increased (p = 0.043). Serum LDL levels at day 42 correlated only with cyst counts of above 300 (found in 44 percent mice), while the change in HDL between days zero and 42 correlated with both the overall mean cyst count (p = 0.041) and cyst counts above 300 (p = 0.044). Calculated per cyst, this decrease in HDL in individual animals ranged from 0.1-17 µmol/L, with a mean of 2.43 ± 4.14 µmol/L. Serum adiponectin levels remained similar between infected and control mice throughout the experiment.

CD40, autophagy and Toxoplasma gondii

Toxoplasmagondii represents a pathogen that survives within host cells by preventing the endosomal-lysosomal compartments from fusing with the parasitophorous vacuoles. The dogma had been that the non-fusogenic nature of these vacuoles is irreversible. Recent studies revealed that this dogma is not correct. Cell-mediated immunity through CD40 re-routes the parasitophorous vacuoles to the lysosomal compartment by a process called autophagy. Autophagosome formation around the parasitophorous vacuole results in killing of the T. gondii. CD40-induced autophagy likely contributes to resistance against T. gondii particularly in neural tissue.

GRA Proteins of Toxoplasma gondii: Maintenance of Host-Parasite Interactions across the Parasitophorous Vacuolar Membrane

The dense granule of Toxoplasma gondii is a secretory vesicular organelle of which the proteins participate in the modification of the parasitophorous vacuole (PV) and PV membrane for the maintenance of intracellular parasitism in almost all nucleated host cells. In this review, the archives on the research of GRA proteins are reviewed on the foci of finding GRA proteins, characterizing molecular aspects, usefulness in diagnostic antigen, and vaccine trials in addition to some functions in host-parasite interactions.

Association of the presence of residual anti-Toxoplasma gondii IgM in pregnant women and their respective family groups in Miracema, Northwest Rio de Janeiro, Brazil

The seroprevalence of toxoplasmosis in 832 pregnant women in Miracema, Rio de Janeiro, was determined and 75.1 percent (625) and 2.0 percent (17) were anti-Toxoplasma gondii IgG and IgM positive, respectively. Out of the 17 IgM positive pregnant women, only one had low avidity IgG corresponding to the acute phase of the infection. All the other women presented with high avidity IgG and also presented with residual IgM anti-T. gondii. Of this sample, 106 received home visits (this includes 11 family nuclei of pregnant women with residual IgM anti-T. gondii, 68 nuclei of only IgG positive pregnant women and 27 nuclei of pregnant women with no antibodies to anti-T. gondii), resulting in 267 individuals visited. Out of these 267 individuals, 21 were positive for IgG and IgM anti-T. gondii and were candidates for the IgG avidity test. All of them presented with high avidity IgG and residual IgM. Five of these IgM+ individuals were (5/238; 2.1 percent) relatives of IgM negative pregnant women. The other 16 (16/29; 55.2 percent) were relatives of IgM+ pregnant women who were positive for residual IgM anti-T. gondii. This association was statistically significant (p = 0.0000). The analysis presented herein raises questions regarding the presence of residual IgM anti-T. gondii such as genetic determinants or even constant antigenic stimuli for the same family cluster.

Avidity of IgG antibodies against excreted/secreted antigens of Toxoplasma gondii: immunological marker for acute recent toxoplasmosis / Avidez de anticorpos IgG anti-antígeno de secreção e excreção de Toxoplasma gondii: marcador imunológico de toxoplasmose aguda recente

Detection of anti-toxoplasma IgM antibodies has frequently been used as a serological marker for diagnosing recently acquired toxoplasmosis. However, the persistence of these antibodies in some patients has complicated the interpretation of serological results when toxoplasmosis is suspected. The purpose of the present study was to evaluate the avidity of IgG antibodies against excreted/secreted antigens of Toxoplasma gondii by means of immunoblot, to establish a profile for acute recent infection in a single serum sample and confirm the presence of residual IgM antibodies obtained in automated assays. When we evaluated the avidity of IgG antibodies against excreted/secreted antigens of Toxoplasma gondii by means of immunoblot, we observed phase-specific reactivity, i.e. cases of acute recent toxoplasmosis presented low avidity and cases of non-acute recent toxoplasmosis presented high avidity towards the 30kDa protein fraction, which probably corresponds to the SAG-1 surface antigen. Our results suggest that the avidity of IgG antibodies against excreted/secreted antigens of Toxoplasma gondii is an important immunological marker for distinguishing between recent infections and for determining the presence of residual IgM antibodies obtained from automated assays.

A detecção de anticorpos IgM antitoxoplasma tem sido freqüentemente utilizada como marcador sorológico para o diagnóstico de toxoplasmose de aquisição recente. Entretanto, a persistência destes anticorpos em alguns pacientes tem complicado a interpretação dos resultados sorológicos quando a toxoplasmose é suspeitada. A proposta deste trabalho foi avaliar a avidez de anticorpos IgG contra antígenos de secreção e excreção de Toxoplasma gondii por immunoblot, para estabelecer um perfil de infecção recente aguda em uma única amostra de soro e confirmar a presença de anticorpos IgM residuais obtidos nos testes automatizados. Quando a avidez de anticorpos IgG contra antígenos de secreção e excreção Toxoplasma gondii, por immunoblot, foi avaliada, observou-se reatividade estágio específica, ou seja, casos de toxoplasmose aguda recente apresentaram baixa avidez e os casos de infecção recente não aguda apresentaram alta avidez para a fração protéica de 30kDa, que corresponde provavelmente ao antígeno de superfície- SAG-1. Nossos resultados sugerem que a avidez dos anticorpos IgG contra antígenos de secreção e excreção Toxoplasma gondii é um importante marcador imunológico para distinguir doença recente de infecção e determinar a presença de anticorpos IgM residuais detectados nos testes automatizados.