RESUMO
The relationship between ingestion of microfilariae (mf), production of infective larvae (L3) and mf density in human blood has been suggested as an important determinant in the transmission dynamics of lymphatic filariasis. Here we assess the role of these factors in determining the competence of a natural vector Culex quinquefasciatus and a non vector Aedes aegypti to transmit Wuchereria bancrofti. Mosquitoes were infected via a membrane feeding procedure. Both mosquito species ingested more than the expected number of microfilariae (concentrating factor was 1.28 and 1.81 for Cx. quinquefasciatus and Ae. aegypti, respectively) but Cx. quinquefasciatus ingested around twice as many mf as Ae. aegypti because its larger blood meal size. Ae. aegypti showed a faster mf migration capacity compared to Cx. quinquefasciatus but did not allow parasite maturation under our experimental conditions. Similar proportions of melanized parasites were observed in Ae. aegypti (2. 4%) and Cx. quinquefasciatus (2.1%). However, no relationship between rate of infection and melanization was observed. We conclude that in these conditions physiological factors governing parasite development in the thorax may be more important in limiting vectorial competence than the density of mf ingested.
Assuntos
Aedes/parasitologia , Culex/parasitologia , Filariose Linfática/transmissão , Insetos Vetores , Microfilárias/isolamento & purificação , Wuchereria bancrofti/isolamento & purificação , Animais , Feminino , HumanosRESUMO
Marsupials have considerable merits as models for studying the developmental dynamics of the mammalian immune system, but until recently there has been a conspicuous lack of specific immune probes to facilitate such studies. To begin a precise study of the ontogeny of the marsupial Didelphis albiventris we have used cross-reactive polyclonal antibodies raised against evolutionarily highly conserved peptides which form part of the antigen specific receptor complexes of human differentiated lymphocytes. Moreover, because of antigen receptor conservation, the antibodies also recognise specifically the immunocompetent T and B lymphocytes of other species including those in the organs of the opossum. Use of the antipeptide antibodies together with other cross-reacting antibodies has allowed us to study the cellular immunology of T and B cells and antigen presenting cells (APC) during the development of thymus, skin, lymph nodes and spleen in the Brazilian white-belly opossum. The molecular nature and identity of the T cell antigens detected in opossum tissues were confirmed by immunoblotting. These findings indicate that it is now possible to exploit these antibody probes for comparative mammalian studies, and indeed to investigate interesting features of the opossum, such as reaction of the immature immune system of the pouch young to antigenic stimulation.
Assuntos
Células Apresentadoras de Antígenos/imunologia , Linfócitos B/imunologia , Gambás/imunologia , Linfócitos T/imunologia , Animais , Anticorpos , Complexo CD3/análise , Antígenos HLA-DR/análise , Sistema Imunitário/crescimento & desenvolvimento , Imunidade Celular , Immunoblotting , Imuno-Histoquímica , Linfonodos/crescimento & desenvolvimento , Mesentério , Gambás/crescimento & desenvolvimento , Peptídeos/imunologia , Pele/crescimento & desenvolvimento , Baço/crescimento & desenvolvimento , Timo/crescimento & desenvolvimentoRESUMO
A detailed ontogenetic immunocytochemical study is reported on gut-associated lymphoid development in the Brazilian marsupial Didelphis albiventris. This employed antibody probes raised to evolutionarily conserved peptides which have been shown to detect HLA-DR-like (class II MHC) antigens and T and B cell markers in a wide range of animal species. Cells with macrophage and dendritic morphology expressing class II MHC and a few cells expressing the T cell marker CD3 were found in the lamina propria of duodenal villi in early (approximately 24 mm crown-rump length) latent opossum. Cells with B cell markers were not detected until lactent animals reached > 60 mm. Development of Peyer's patches (PP) was seen first in the duodenum in 45-60 mm lactent animals, progressing to well developed PP in the duodenum and ileum in lactent animals > 80 mm. These PP, like those in weanling and juvenile animals, consisted of follicles with a network of class II MHC positive dendritic cells and round cells lacking T and B markers, but lacking well defined mantle zones. B cells were present mainly in the lymphatic sinuses, with CD3 T cells present between follicles in the PP and intraepithelially in the villi. The study reveals the sequential development of class II MHC positive dendritic cells, T cells and B cells in the intestinal ontogeny of the opossum PP. These features occurred initially exclusively in the duodenum and subsequently in the ileum, paralleling the physiological maturation of the gut in eutheria.
Assuntos
Gambás , Nódulos Linfáticos Agregados/crescimento & desenvolvimento , Sequência de Aminoácidos , Animais , Linfócitos B/citologia , Linfócitos B/imunologia , Complexo CD3/análise , Células Dendríticas/citologia , Células Dendríticas/imunologia , Duodeno/citologia , Antígenos de Histocompatibilidade Classe II/análise , Íleo/citologia , Imunoglobulina A/análise , Imuno-Histoquímica/métodos , Macrófagos/citologia , Macrófagos/imunologia , Dados de Sequência Molecular , Nódulos Linfáticos Agregados/citologia , Linfócitos T/citologia , Linfócitos T/imunologiaRESUMO
Separation of the blood forms of trypanosomes from the blood of infected animals is difficult, especially in the case of Trypanosoma cruzi Y strain. Two procedures to isolate the Y strain blood forms of T. cruzi using polyvinyl pyrrolidone-coated silica (percoll) and histopaque are reported in this study. The recovery rates of parasites were 16 +/- 5 and 68 +/- 16%, respectively. The parasites isolated by these methods presented normal motility and morphology and were infective to albino mice with prepatent periods, parasitemia curves, and polymorphism patterns during the infection that were similar to those of control parasites. In addition, the preservation of surface antigens was confirmed by immunocytochemical studies.