Avaliação da imunização de hamsters com plasmídeos que codificam componentes salivares de Lutzomiya longipalpis (LJM19) e/ou antígeno parasitário (KMP11) contra a infecção com Leishmania chagasi / Evaluation of immunization of hamsters with plasmids encoding salivary components of Lutzomyia longipalpis (LJM19) and / or parasite antigen (KMP11) against infection with Leishmania chagasi

Hamsters têm sido utilizados como modelos experimentais visando compreender os mecanismos de respostas imunes contra espécies de Leishmania do complexo donovani. Estes modelos são capazes de reproduzir muitas das manifestações clínicas da leishmaniose visceral humana. Estudos recentes demonstraram que a imunização de hamsters com plasmídeos codificantes para proteínas salivares (LJM19) de Lutzomyia longipalpis, vetor de L. chagasi, bem como antígenos parasitários (KMPl1) protege hamsters contra um desafio letal com Leishmania chagasi. Neste trabalho, hamsters foram utilizados para avaliar o efeito protetor contra uma infecção por L. chagasi utilizando imunização com os plasmídeos que codificam as proteínas LJM19 e KMP11 administrados em conjunto. A imunização com os plasmídeos induziu a produção de IFN-y nos linfonodos drenantes do local das imunizações quando os animais foram avaliados 7, 14 e 21 dias após a última imunização. Uma vez imunizados e desafiados com L. chagasi mais saliva do vetor, os animais mostraram maiores relações (...) nos linfonodos drenantes quando mensuradas 7 e 14 dias após o desafio. Quando avaliados 2 e 5 meses após o desafio, os animais imunizados mostraram menores cargas parasitárias no baço e no fígado e maiores relações (...) no baço 2 meses após o desafio. Além disso, os hamsters imunizados apresentaram maior conservação da arquitetura histológica do baço e do fígado nos tempos avaliados e não desenvolveram distúrbios hematológicos quando comparados com animais controles sadios.

Contudo, efeito protetor adicional pela imunização com os diferentes plasmídeos administrados em conjunto não foi observado em relação às imunizações com os plasmídeos separados. Comparações entre rotas de administração de plasmídeos foram estudadas utilizando as vias intradérmica e intramuscular. Os grupos de animais que receberam a imunização intradérmica apresentaram uma proteção mais prolongada quando comparados aos animais imunizados intramuscularmente. Estes resultados mostram que apesar da combinação de plasmídeos não induzir maior proteção que os plasmídeos separados, a via de imunização intradérmica pode conferir uma proteção mais duradoura quando comparada com a imunização pela via intramuscular.

Clinical studies on bronchial asthma caused by contact with hamsters.

Bronchial asthma induced by contact with hamsters and other small rodents is receiving higher attention from the medical profession not only because of the problem of laboratory animal allergies (LAA), but also because of increasing household allergens for asthma, since keeping these pets has become more common in Japanese homes. The present report describes our studies on the backgrounds of nine patients with asthma who kept Dzungarian Dwarf hamsters as household pets. The following features were recognized among patients with bronchial asthma induced by contact with hamsters: 1) earlier onset of symptoms than for keeping other household pets, at an average of 14.7 months or within 12 months in 78% of the cases following the start of pet keeping; 2) adults ranging from their late 30s to 40s who have children of primary school age; 3) dwelling in apartments; 4) relatively high level of serum IgE and ECP; 5) positive for both immediate and late type asthmatic responses on an inhaling induction test; and 6) rapid remission after the cessation of pet keeping.

Isolation of Paracoccidoides brasiliensis from armadillos (Dasypus novemcinctus) captured in an endemic area of paracoccidioidomycosis

Paracoccidioides brasiliensis, the causative agent of paracoccidioidomycosis (PCM), was first isolated from the Amazonian gerion where the mycosis is uncommon. In the present study, we report on the high incidence of PCM infection in armadillos from a hyperendemic region of the disease. Four nine-banded armadillos (Dasypus novemcinctus) were captured in the endemic area of Botucatu, Sao Paulo, Brazil, killed by manual cervical dislocation and autopsied under sterile conditions. Fragments of lung, spleen, liver and mesenteric lymph nodes were precessed for histology, cultured on Mycosel agar at 37ºC, and homogenized for inoculation into the testis and peritoneum of hamster. The animals were killed from week 6 to week 20 postinoculation and fragments of liver, lung, spleen, testis, and lymph nodes were cultured on brain heart infusion agar at 37ºC. Paracoccidioides brasiliensis was isolated from three armadillos both by direct organ culture and from the liver, spleen, lung, and mesenteric lymph node hamster. In addition, one positive armadillo presented histologically proven PCM disease in a mesenteric lymph node. The three aramdillos isolates (Pb-A1, Pb-A2, and Pb-A4) presented thermodependent dimorphism, urease activity, and casein assimilation, showed amplification of the gp43 gene, and were highly virulent in intratesticulary inoculation hamster. The isolates expressed the gp43 glycoprotein, the immunodominant antigen of the fungus, and reacted with a pool of sera from PCM patients. Taken together, the present data confirm that armadillos are a natural reservoir of P. brasiliensis and demonstrate that the animal is a sylvan host to the fungus

Immunological pattern in Syrian golden hamsters experimentally infected with schistosoma mansoni and Leishmania D. infantum

The immunoglobulins [IgG, IgM, IgE and IgA] and the complements [C3 and C4] were studied in hamsters as result of a single infection [S. mansoni or L. D. infantum] and as concomitant infection [L. D. infantum on top of S. mansoni]. The immunological pattern showed profound IgG and IgA increase in the concomitant group than either infection alone. Also, concomitant infection induced more IgE increase than either infection alone. On the other hand, C3 and C4 showed more decrease in concomitant infection. The whole results were discussed

Immunological properties of cellular and whole-culture leptospiral bacterins

Two bivalent leptospiral bacterins were compared for safety in guinea pigs and for potency in hamsters. One bacterin [Bacterin A] was prepared from the cellular material of Leptospiral icterohaemorrhagjae and Leptospira canicola cultures propagated in Stuart's modified medium with 7% rabbit serum. The 2[nd] bacterin [Bacterin B] contained whole leptospiral cultures grown in synthetic medium. Neither bacterin induced adverse local or systemic reactions when injected intraperitoneally [I/P] in guinea pigs. In hamsters, 1/400 and 1/800 of the recommended dose of bacterin B for cattle protected 100% of the vaccinated hamsters against challenge exposure of either virulent leptospiral serotype A dose representing 1/400 of the recommended dose of bacterin A for cattle protected 80% of vaccinated hamsters against challenge exposure to L. icterohaemorrhagjae and 90% against challenge exposure to L. canicola, whereas the 1/800 dose level protected only 10% of the vaccinated hamsters challenge exposed to virulent culture of L. icterohaemorrhagjae or canicola. The Possibility was demonstrated that at least one soluble antigen of strong immunogenic properties is produced in cultures of L. icterohaemorrhagjae and L. canicola

Induction of macrophage killing of Leishmania donovani by human CD4+ T cell clones

Immunitary in leishmaniasis is mediated by T cells, but protective responses in humans have not been fully defined. In this study, the functional activity of CD4+ T cell clones derived from an immune individual was investigated to identify potentially protective responses. The T cells proliferated and produced interferon-gamma (IFN-gamma) in response to a soluble Leishmania donovani antigen extrac and live amastigotes. There was considerable variation in the anti-leishmanial activity of the T cell clones when they were co-cultured with L. donavani infected monocytes isolated from an HLA-DR,DQ mathced donor. All of the clones which demonstrated antigen specific reactivity by proliferation or cytokineproduction induced some dregee of inhibition of intracellular parasite replication, but only a few of the clones induced pronounced leishmanicidal activity. There was strong correlation between the level of amastigote-induced IFN-gamma secretion and anti-leishmanial activity. This approach anables the identification of potentially protective immune responses in humans at the clonal level, and offers a means for the identification of the relevant antigen(s)

Natural killer cell activity in experimental paracoccidioidomycosis of the syrian hamster

Com o objetivo de avaliar a atividade de celulas natural killer na paracoccidioidomicose experimental do hamster, 80 hamsters foram infectados por via intratesticular com Paracoccidioides brasiliensis e sacrificados apos 24h, 48h, 96h, 1, 2, 4, 8 e 11 semanas de infeccao. Como controle foram avaliados 40 hamsters normais, nao infectados. Os animais foram submetidos ao estudo da atividade citotoxica de celulas NK pela tecnica de "single-cell assay" e da resposta imune humoral pelas tecnicas de imunodifusao dupla e Elisa...

Evidence for immune response of hamster against s mansoni

Immunity was employed according to the following protocol using adult male hamsters: Group 1 [injected subcutaneously with normal saline], group 2 [immunized subcutaneously with 150 irradiated cercariae/hamster [20 kRad]], and group 3 [infected subcutaneously with 150 normal cercariae/hamster [concomitant immunity]]. A total of 36 hamsters/group were reclassified into six subgroups according to the following sensitization period 7, 14, 28, 42, 56 and 84 days post-vaccination. At the end of each sensitization period, six hamsters were challenged through abdominal infection with 100 cercariae/hamster. Sera of blood samples withdrawn weekly post-cercarial challenge for 12 weeks were employed for monitoring of antibodies titer by the following three coating antigens [cercarial, egg and adult worm homogenates] using ELISA technique. The data obtained revealed that both control group 1 and reinfected group 3 displayed progressive immune at 4th and 5th weeks post-challenge [around the time of worm formation and egg-laying commences]. Sera of group 2 revealed that the use of cercarial homogenates, as a coating antigen, displayed early +ve antibody formations. The use of egg homogenate revealed +ve antibody formations during the time of egg-laying commences. Meanwhile, a wide range of +ve antibody formations were concomitant with the use of adult worm homogenate as a coating antigen. Sacrificing the hamster at the end of 12 weeks post-challenge and counting the number of worms revealed that best vaccination was displayed by irradiated cercariae, which elicited progressive resistance to S. mansoni infection that was increased by time of sensitization reaching a very highly significant in magnitude

Investigaçäo sobre a presença de leptospiras nos ovários de hamsters experimentalmente infectados com Leptospiras interrogans sorotipo pomona / Investigation on the presence of leptospires in ovaries of hamsters experimentally infected with Leptospiras interrogans serovar pomona

De 90 hamsters primíparas com 80 a 120 gramas de peso vivo, 75 foram inoculadas com a dose individual de 0,5 ml de estirpe virulenta do sorotipo pomona (30 a 40 leptospiras ativas por campo microscópico, no aumento de 200 vezes) e as 15 remanescentes constituíram o grupo testemunho näo infectado. Todos os animais tratados com leptospiras apresentaram os sinais da infecçäo (prostraçäo, taquipnéia, eriçamento do pelame, icterícia e hemorragias nasal, bucal e perineal) e foram sacrificados por ocasiäo da fase agônica da doença, situada entre o quarto e o sétimo dia da inoculaçäo. Nesta oportunidade, os ovários foram colhidos em condiçöes assépticas e submetidos à técnica de visualizaçäo de leptospiras (exame direto em microscopia de campo escuro, coloraçäo argêntica de Levaditi e reaçäo de imunofluorescência direta), cultivo em meio de Fletcher e exame histopatológico (coloraçäo de hematoxilina e eosina). A ocorrência de uma possível contaminaçäo estabelecida durante a retirada dos ovários foi investigada através da lavagem em soluçäo salina tamponada estéril. As leptospiras foram demonstradas em todos os ovários do grupo de animais experimentalmente inoculados (lavados e näo lavados), através da coloraçäo de Levaditi, reaçäo imunofluorescência direta e também no cultivo em meio de Fletcher. O exame direto em microscopia de campo escuro mostrou ser uma técnica muito pouco sensível. O exame das preparaçöes submetidas à coloraçäo argêntica possibilitou a visualizaçäo de leptospiras em diferentes estruturas dos ovários, incluindo: o interstício, a zona pelúcida e o interior dos óvulos. Os exames histopatológicos permitiram observar as alteraçöes morfológicas típicas de um processo inflamatório agudo em 57 por cento dos ovários examinados