RESUMO
Neospora caninum is an Apicomplexan protozoan that has the dog as a definitive host and cattle (among other animals) as intermediate hosts. It causes encephalopathy in dogs and abortion in cows, with significant loss in worldwide livestock. As any Apicomplexan, the parasite invades the cells using proteins contained in the phylum-specific organelles, like the micronemes, rhoptries and dense granules. The aim of this study was the characterization of a homologue (denominated NcMIC2-like1) of N. caninum thrombospondin-related anonymous protein (NcMIC2), a micronemal protein previously shown to be involved in the attachment and connection with the intracellular motor responsible for the active process of invasion. A polyclonal antiserum raised against the recombinant NcMIC2-like1 functional core (thrombospondin and integrin domains) recognized the native form of NcMIC2-like1, inhibited the in vitro invasion process and localized NcMIC2-like1 at the apical complex of the parasite by confocal immunofluorescence, indicating its micronemal localization. The new molecule, NcMIC2-like1, has features that differentiates it from NcMIC2 in a substantial way to be considered a homologue.
Assuntos
Neospora/patogenicidade , Proteínas de Protozoários/metabolismo , Homologia de Sequência de Aminoácidos , Sequência de Aminoácidos , Animais , Chlorocebus aethiops , Imunofluorescência , Microscopia Confocal , Dados de Sequência Molecular , Neospora/metabolismo , Neospora/ultraestrutura , Proteínas de Protozoários/química , Proteínas de Protozoários/genética , Análise de Sequência de DNA , Células Vero/parasitologiaRESUMO
Cellular and humoral immune response, as well as cytokine gene expression, was assessed in Nelore cattle with different degrees of resistance to Cooperia punctata natural infection. One hundred cattle (male, weaned, 11-12 months old), kept together on pasture, were evaluated. Faecal and blood samples were collected for parasitological and immunological assays. Based on nematode faecal egg counts (FEC) and worm burden, the seven most resistant and the eight most susceptible animals were selected. Tissue samples of the small intestine were collected for histological quantification of inflammatory cells and analysis of cytokine gene expression (IL-2, IL-4, IL-8, IL-12p35, IL-13, TNF-alpha, IFN-gamma, MCP-1, MCP-2, and MUC-1) using real-time RT-PCR. Mucus samples were also collected for IgA levels determination. Serum IgG1 mean levels against C. punctata antigens were higher in the resistant group, but significant differences between groups were only observed 14 days after the beginning of the experiment against infective larvae (L3) and 14 and 84 days against adult antigens. The resistant group also presented higher IgA levels against C. punctata (L3 and adult) antigens with significant difference 14 days after the beginning of the trial (P<0.05). In the small-intestine mucosa, levels of IgA anti-L3 and anti-adult C. punctata were higher in the resistant group, compared with the susceptible group (P<0.05). Gene expression of both T(H)2 cytokines (IL-4 and IL-13) in the resistant group and T(H)1 cytokines (IL-2, IL-12p35, IFN-gamma and MCP-1) in the susceptible group was up-regulated. Such results suggested that immune response to C. punctata was probably mediated by T(H)2 cytokines in the resistant group and by T(H)1 cytokines in the susceptible group.
Assuntos
Doenças dos Bovinos/genética , Citocinas/metabolismo , Perfilação da Expressão Gênica/veterinária , Predisposição Genética para Doença , Infecções por Nematoides/veterinária , Animais , Bovinos , Doenças dos Bovinos/imunologia , Doenças dos Bovinos/parasitologia , Citocinas/genética , Regulação da Expressão Gênica/fisiologia , Imunoglobulina A , Infecções por Nematoides/imunologia , Infecções por Nematoides/parasitologiaRESUMO
In vitro tests were carried out to verify the activity of 26 Brazilian isolates of predatory fungi of the genus Arthrobotrys on a free-living nematode (Panagrellus sp.) and on infective larvae of Cooperia punctata, a parasitic gastrointestinal nematode of cattle. The results showed that the free-living nematode Panagrellus sp. was the most preyed upon, compared to C. punctata, for all the fungal treatments. Also, variable predatory capacity was observed for different fungal isolates belonging to the same genus when applied to different nematode species.
Assuntos
Fungos Mitospóricos/patogenicidade , Nematoides/microbiologia , Controle Biológico de Vetores , Animais , Bovinos , Larva , Fungos Mitospóricos/isolamento & purificação , Especificidade da EspécieRESUMO
In vitro tests were carried out to verify the activity of 26 Brazilian isolates of predatory fungi of the genus Arthrobotrys on a free-living nematode (Panagrellus sp.) and on infective larvae of Cooperia punctata, a parasitic gastrointestinal nematode of cattle. The results showed that the free-living nematode Panagrellus sp. was the most preyed upon, compared to C. punctata, for all the fungal treatments. Also, variable predatory capacity was observed for different fungal isolates belonging to the same genus when applied to different nematode species
Assuntos
Animais , Bovinos , Técnicas In Vitro , Fungos Mitospóricos/patogenicidade , Nematoides/microbiologia , Larva , Fungos Mitospóricos/isolamento & purificação , Controle Biológico de VetoresRESUMO
The dynamics of the humoral immune response of calves were analysed after primary infection and re-infection with the intestinal nematode Cooperia punctata. 12 male 5 month-old Holstein-Friesian calves were randomly divided into two groups A and B. At the beginning of the experiment Group A animals were each infected experimentally with a single oral dose of 130,000 infective third stage larvae (L3) of C. punctata. The animals of Group B were kept as non-infected controls. The two calves from Group A with the highest infections died of cooperiosis at 32 and 44 days after infection (DAI), respectively. On DAI 100 the calves were treated with the recommended dose of oxfendazole. On DAI 180 the remaining four calves of Group A and three animals of Group B (B1) were infected with 260,000 L3 of C. punctata, while the other three calves of Group B (B2) served as non-infected controls. Monitoring of the humoral immune response predominantly demonstrated an IgG1 response against both adult and L3 antigen of C. punctata. Moreover, re-infections increased the levels of these immunoglobulins. IgA levels were less increased than IgG1 and no significant increase was observed in IgG2 and IgM levels. Immunoblotting analysis showed that total IgG present in the serum of the primary infected animals mainly reacted against adult proteins of 12-14 and 17-20 kDa and against L3 proteins of 33 and 43 kDa. After re-infection total IgG reacted with the same adult proteins but also with an adult 29 kDa protein.