Humoral immune response to filarial antigens in chyluria

Humoral immune parameters like total immunoglobulins and specific antibody levels in serum were studied in filarial chyluria patients. Mean serum IgG was significantly reduced in this group compared to normal controls, while IgA and IgM levels remained comparable to controls. Anti-filarial antibody titre as measured by enzyme-linked immunosorbent assay also was significantly reduced. However, the total and specific IgE antibody titre was similar to that of controls. Specific IgE contents of the patients’ sera could be related to their microfilaraemic status

Pregnancy Outcome and Placenta Pathology in Plasmodium berghei ANKA Infected Mice Reproduce the Pathogenesis of Severe Malaria in Pregnant Women

Pregnancy-associated malaria (PAM) is expressed in a range of clinical complications that include increased disease severity in pregnant women, decreased fetal viability, intra-uterine growth retardation, low birth weight and infant mortality. The physiopathology of malaria in pregnancy is difficult to scrutinize and attempts were made in the past to use animal models for pregnancy malaria studies. Here, we describe a comprehensive mouse experimental model that recapitulates many of the pathological and clinical features typical of human severe malaria in pregnancy. We used P. berghei ANKA-GFP infection during pregnancy to evoke a prominent inflammatory response in the placenta that entails CD11b mononuclear infiltration, up-regulation of MIP-1 alpha chemokine and is associated with marked reduction of placental vascular spaces. Placenta pathology was associated with decreased fetal viability, intra-uterine growth retardation, gross post-natal growth impairment and increased disease severity in pregnant females. Moreover, we provide evidence that CSA and HA, known to mediate P. falciparum adhesion to human placenta, are also involved in mouse placental malaria infection. We propose that reduction of maternal blood flow in the placenta is a key pathogenic factor in murine pregnancy malaria and we hypothesize that exacerbated innate inflammatory responses to Plasmodium infected red blood cells trigger severe placenta pathology. This experimental model provides an opportunity to identify cell and molecular components of severe PAM pathogenesis and to investigate the inflammatory response that leads to the observed fetal and placental blood circulation abnormalities

Towards the Establishment of a Porcine Model to Study Human Amebiasis

BACKGROUND: Entamoeba histolytica is an important parasite of the human intestine. Its life cycle is monoxenous with two stages: (i) the trophozoite, growing in the intestine and (ii) the cyst corresponding to the dissemination stage. The trophozoite in the intestine can live as a commensal leading to asymptomatic infection or as a tissue invasive form producing mucosal ulcers and liver abscesses. There is no animal model mimicking the whole disease cycle. Most of the biological information on E. histolytica has been obtained from trophozoite adapted to axenic culture. The reproduction of intestinal amebiasis in an animal model is difficult while for liver amebiasis there are well-described rodent models. During this study, we worked on the assessment of pigs as a new potential model to study amebiasis. METHODOLOGY/PRINCIPAL FINDINGS: We first co-cultured trophozoites of E. histolytica with porcine colonic fragments and observed a disruption of the mucosal architecture. Then, we showed that outbred pigs can be used to reproduce some lesions associated with human amebiasis. A detailed analysis was performed using a washed closed-jejunal loops model. In loops inoculated with virulent amebas a severe acute ulcerative jejunitis was observed with large hemorrhagic lesions 14 days post-inoculation associated with the presence of the trophozoites in the depth of the mucosa in two out four animals. Furthermore, typical large sized hepatic abscesses were observed in the liver of one animal 7 days post-injection in the portal vein and the liver parenchyma. CONCLUSIONS: The pig model could help with simultaneously studying intestinal and extraintestinal lesion development

Os estudos em malária aviária e o Brasil no contexto científico internacional (1907-1945)

Aborda a contribuição de cientistas brasileiros aos estudos sobre o protozoário causador da malária. Ao colocar em foco os trabalhos de Henrique Aragão e Wladimir Lobato Paraense, destaca a importância da malária aviária para o entendimento da malária humana e sua terapêutica, a rede de relações científicas estabelecidas, as agendas comuns de pesquisa, as trocas de informações entre pesquisadores, assim como o papel por eles desempenhado no contexto internacional das descobertas científicas.The article explores Brazilian investigators' contributions to research on the protozoan causative agent of malaria. Focusing on the work of Henrique Aragão and Wladimir Lobato Paraense, it underscores the importance of avian malaria in elucidating human malaria and treatment options, and also examines the network of scientific relations forged by these researchers, their shared research agendas, exchange of information with other researchers, and role within the international context of scientific discoveries

Antigenic Relationships Between Polymorphic and Monomorphic Strains of the <i>Brucei</i> Group Trypanosomes

Summary The antigenic relationships between the Brucei group trypanosomes have been examined. The serum of infected sheep has been used as a source of antibody and a respiratory technique empolyed to measure the cross-reactions to specific antibody. Antibody to polymorphic strains is relatively specific although a weak cross-reaction with other polymorphic and monomorphic strains may be demonstrated. After prolonged maintenance by mechanical passage in laboratory animals and the resultant loss of the polymorphic character, the antigenic distinctions between the three species tend to disappear. There is almost complete cross-reactivity between monomorphic strains of the three species comprising the Brucei group.</jats:p