Browsing by Author "Gazzinelli, Giovanni"

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    Differential impact of metacyclic and blood trypomastigotes on parasitological, serological and phenotypic features triggered during acute Trypanosoma cruzi infection in dogs.
    (2007) Carneiro, Cláudia Martins; Martins Filho, Olindo Assis; Reis, Alexandre Barbosa; Veloso, Vanja Maria; Araújo, Flávio Marcos Gomes de; Bahia, Maria Terezinha; Lana, Marta de; Coelho, George Luiz Lins Machado; Gazzinelli, Giovanni; Oliveira, Rodrigo Corrêa de; Tafuri, Wagner Luiz
    Differential impact of metacyclic and blood trypomastigotes on parasitological, serological and phenotypic features triggered during acute Trypanosoma cruzi infection in dogs A detailed follow-up investigation of the major parasitological, serological and phenotypic features in dogs experimentally infected with metacyclic (MT) and blood (BT) trypomastigotes of Trypanosoma cruzi strain Berenice-78, typifying vectorial and transfusional transmission of human Chagas disease, has been conducted. Although there were no changes with respect to the window of patent-parasitaemia, significant differences between MT- and BT-infected dogs in both the prepatent period (days 23 and 19, respectively) and the day of maximum parasitaemia (days 26 and 22, respectively) were recorded. A progressive enhancement in the level of T. cruzi -specific antibodies accompanied infection by both MT and BT forms, although higher IgG titres developed on days 14 and 21 following infection with MT forms. Higher Thy-1 + /CD21 + and lower CD4 + /CD8 + cell ratios, occasioned by increased levels of Thy-1 + and CD8 + T-cells and reduced frequencies of CD4 + T-cells and CD21 + B-lymphocytes, were observed in both MT- and BT-infected animals. The reduced frequency of CD14 + leukocytes was revealed as the most relevant phenotypic feature intrinsic to T. cruzi infection independent of inoculum source. BT-specific phenotypic features included an early reduction
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    Granulomatous hypersensitivity to Schistosoma mansoni egg antigens in human schistosomiasis. IV. A role for prostaglandin-induced inhibition of in vitro granuloma formation.
    (1994) Goes, Alfredo Miranda de; Rezende, Simone Aparecida; Gazzinelli, Giovanni; Doughty, Barbara L.
    The prostaglandins (PG) are known to regulate immune cell function (s) and participate in the progression of both acute and chronic inflammatory reactions. Using an in vitro model of Schistosoma mansoni egg-induced hypersensitivity granulomas, we have delineated the role of immune complexes (IC) in the induction andrelease of PG and their inhibitory effects on granuloma development. The hypersensitivity- type granuloma reaction to soluble egg antigen (SEA) was examined using a model of in vitro granuloma ,formation. Our results show that granuloma formation was dramatically suppressed by the addition to the granuloma cultures of IC, PGE,, PGE2, while PGF, alpha had no significant effect. The inhibition of the PG function was achieved by the introduction of anti-PG antibodies that blocked suppression of granuloma,formation. It appears in this model system that IC may inhibit the activity of granuloma formation by stimulating the monocyte-macrophage lineage to release inhibitory mediators. Our results suggest that the prostaglandins E series may be important in the generation and maintenance of suppression of the granulomatous inflammatory response to S. mansoni egg antigens .