Moysés Sadigursky

Um estudo comparativo das cepas Feira de Santana (Bahia) e Porto Rico do Schistosoma Mansoni na infecção experimental do camundongo

A comparative study of mice infected either with the Porto Rican or a Brazilian (Feira de Santana) strain of Schistosoma mansoni failed to show any difference regarding recovery of five day lung worms, recovery of adult worms from the portal system, number of eggs per gram of tissue in liver and intestines, histopathology or mortality rate. In fact, the differences, although small, were greater among animals infected with the same strain, that when the total results from both strains were compared.

Observações sobre calazar em Jacobina, Bahia. VI - Investigações sobre reservatórios silvestres e comensais

From 1982 to 1986, investigations on the natural infection with leishmanias of the sylvatic and commensal mammals were carried out around the city of Jacobina, Bahia, one of the oldest endemic foci of visceral leishmaniasis in Brazil. The species of Marsupialia Didelphis albiventris predominated, with the rate of 44%, over the total of 213 specimens belonging to only 11 different species of mammals collected there. Among the 84 specimens of D. albiventris examined, 2(2.3%) were infected with Leishmania donovani sensu lato; 1 with L. mexicana amazonensis, 1 with L. braziliensis sub species, and 3 with Trypanosoma cruzi. Also, amastigote suspected bodies were seen in the smears of spleens and livers of 3 Dasyprocta aguti, 1 Cercomys cunnicularius and 1 Oryzomys sp. Although strengthened by some epidemiological evidences, such as specific predominancy, peri domestic and domestic occurrence, attractivenessfor the vector Lutzomyia longipalpis and the concomitancy with human cases of visceral leishmaniasis at the same place, the low rate of the natural infection of D. marsupialis still do not allow a definitive conclusion that the oppossum is a primary and the most important reservoir of visceral leishmaniasis in Jacobina.

Infectivity of Leishmania promastigotes is associated with surface antigenic expression

Differentiation between a non-infective and an infective Leishmania promastigote population was demonstrated. Promastigotes in the stationary phase (day 5) were found to be highly infective in vitro to BALB/c mouse peritoneal macrophages, compared with those of the logarithmic phase (day 3). The infective promastigotes showed surface antigenic determinants different from non-infective ones. Polyclonal anti-3 day and anti-5 day antibodies were bound specifically to the surface of corresponding promastigotes in both SRIA and IFAT; no strong cross-reactions were observed otherwise. Also, polyclonal anti-5 day but not anti-3 day antibodies recognized efficiently the antigenic molecules on the surface of late stage (day 7) sandfly promastigotes. This clearly indicates the appearance of new antigenic molecules on the surface of infective promastigote forms. Intracellular multiplication of Leishmania was significantly inhibited by anti-5 day antibodies compared with anti-3 day antibodies. The presence of new surface molecules on late stage promastigotes may contribute to Leishmania infectivity.

Immunofluorescence studies of schistosome structures which share determinants with circulating schistosome antigens

An attempt was made to demonstrate by immunofluorescence the presence and location of antigens sharing determinants with circulating schistosomal antigens (CSA) (BAWDEN & WELLER, 1974; NASH et al., 1974) in several developmental stages of Schistosoma mansoni. We also studied the immunoglobulin (Ig) class of antibodies in patients’ serum that attach to sites where CSA determinants are found. Both cryostat sections of material frozen in liquid nitrogen (196°C) and Bouin-fixed paraffinembedded sections were used. Material consisted of cercariae, skin-penetrating schistosomula, fiveday migrating schistosomula, adult worms and eggs of S. mansoni. The location of CSA determinants in the schistosomal preparations was detected by indirect immunofluorescence, using specific antiserum to CSA (NASH et al., 1974) and fluoresceinconjugated goat anti-rabbit globulin (Hyland Laboratories, Los Angeles, Cal., U.S.A.).

Parasite and Egg Burden, Hepatic Collagen and Histologic Pattern of Liver Granulomas in Selection III High and Low Antibody Responder Mice Infected with Schistosoma mansoni

Selection III mice have particular immunological characteristics: they are high (H III) or low (L III) antibody producer animals, yet both lines display similar T cell responses and macrophage activities. We submitted these mice to infection with Schistosoma mansoni to assess in vivo parasite and egg burden, hepatic collagen and cellular composition of granulomas in both lines. Titration of anti-Schistosoma IgG by ELISA showed remarkably higher values in H III line, at both studied periods (8th and 12th weeks post-infection). Nevertheless, the number of adult worms recovered from the portal system was similar in both lines, being not associated with anti-Schistosoma antibody levels. There is an increase in hepatic collagen from the 8th to the 12th weeks post-infection, which is paralleled by an increase in the number of eggs in the liver. This association apparently occurs at the same ratio in H III and L III animals. The most important difference found between the two lines was the outstanding contrast in terms of volume and eosinophil counts in the granulomas, with lesions from H III mice clearly being larger and containing more of these cells than LIII lesions.

Evaluation of spleen cell population and effect of splenectomy on granuloma modulation in BALB/c mice infected with Schistosoma mansoni

A kinetic study of the cells present in the spleen of BALB/c mice infected with Schistosoma mansoni was carried out. The lymphocytes were evaluated phenotypically with monoclonal antibodies and the effect of splenectomy on the modulation of periovular granuloma was also investigated. The infected mice had proportional increases in the numbers of neutrophils, plasma cells, macrophages and eosinophils in the spleen. The largest number of neutrophil, plasma cells and macrophage were found between the 8th and the 12th week of infection, while the amount of eosinophils were higher later on, around the 20th week. The lymphocytes phenotypically characterized as Thy 1.2, Lyt 1.2 (CD4) increased mildly in proportional numbers. However, the percentage of lymphocytes with the Lyt 2.2 (CD8) phenotype, which is characteristic of suppressor and cytotoxic T cells, increased significantly with the progress of the disease. The numbers of B lymphocytes, which comprise 50% of the mononuclear cells present in the spleen, increased significantly till the 16th week when they began to decrease. The mean diameters of periovular granulomas were comparatively similar in both experimental groups (splenectomized and non-splenectomized mice). However, the evolutive types of granuloma (exudative, intermediate and fibrous) in splenectomized mice were proportionally different from those of non splenectomized mice in the 16th and 24th week of infection. It is inferred that lymphnodes or other secondary lymphoid organs, in the absence of the spleen, assume a modulating action on periovular granulomas, although the evolution of the granulomas is somehow delayed in splenectomized mice.

Induced tolerance to Schistosoma mansoni antigens modulates periovular granuloma

Immunological tolerance to Schistosoma mansoni antigens induced by oral exposure of neonatal and adult mice to adult worm, soluble egg and polysaccharide antigens conducted to modulated periovular granuloma of infected mice. However the tolerance do not interfere in the infection. The estimative population and subpopulation of lymphocytes in the spleen of tolerized (not infected) animals do not differ from normal animals but Lyt 2.2 reactive lymphocytes to Schistosoma antigens was demonstrated in the tolerized animals.

Studies on anti-component 5 antibodies in animals infected with Trypanosoma cruzi

A competitive antibody enzyme immunoassay, using a monoclonal antibody against the species-specific Trypanosoma cruzi antigen 5, was used to investigate the presence o f anti-component 5 antibodies in sera of opossums, dogs, rabbits and rats infected with this parasite. The sera from 51 Venezuelan patients with Chagas’disease were also tested. About 90% of the infected subjects showed significant levels o f anti-component 5 antibodies. Nevertheless, these antibodies were not detected in the sera o f dogs, rats and opossums infected with T. cruzi. Some sera from infected rabbits presented significant results but close to the limit o f positivity o f the test. Thesefindings suggest that the immune response in animals naturally or experimentally infected with T. cruzi is different from that observed in human Chagas’disease.