Anti-leptospirosis agglutinins in Brazilian capybaras (hydrochoerus hydrochaeris)

The interest in commercial use of wild animals is increasing, especially regarding raising of capybaras. Although this wild species is potentially lucrative for the production of meat, oil and leather, it is suggested as a probable reservoir of leptospires. Methods Due to the economic importance of this species and the lack of studies concerning leptospirosis, the presence of anti-leptospirosis agglutinins was assayed in 55 serum samples of capybaras (Hydrochoerus hydrochaeris) from commercial and experimental breeding flocks located in São Paulo state, Paraná state, and Rio Grande do Sul state, Brazil. Samples were obtained through cephalic or femoral venipunction (5 to 10 mL). Microscopic agglutination test was used according to the Brazilian Health Ministry considering as cut-off titer of 100. Results Out of the 55 samples analyzed, 23 (41.82 %) tested positive. The most prevalent serovar was Icterohaemorrhagiae (56.52 %) in 13 samples, followed by Copenhageni in nine samples (39.13 %), Pomona in four samples (17.39 %), Djasiman and Castellonis in three samples each (13.04 %), Grippotyphosa, Hardjo, Canicola, and Cynopteri in two samples each (8.7 %), and Andamana and Bratislava in one sample each (4.34 %). Conclusions These results suggest the evidence of exposure toLeptospira spp. and the need of new studies to evaluate a higher number of capybaras from different regions to better understand the importance of leptospirosis infection in these animals and verify the zoonotic role of this species as a possible source of infection to humans and other animals.

Avaliação de fatores de risco de cães sororreagentes à leptospira spp. e sua distribuição espacial, em área territorial urbana / Risk factor evaluation and spatial distribution analysis for urban dogs serum reactive to Leptospira spp

Objetivou-se avaliar os fatores de risco de cães sororreagentes à aglutinina antileptospírica e sua distribuição espacial, em uma área territorial urbana. Foram colhidas 1.000 amostras de sangue de cães, em 20 postos, distribuídos, homogeneamente, pela área territorial urbana de 32Km elevado a 2 da cidade de Botucatu, Estado de São Paulo, Brasil. O diagnóstico foi realizado pela prova de soroaglutinação microscópica, com 24 sorovares de Leptospira spp. A análise estatística foi feita por meio do teste de Goodman, considerando-se o nível de 5% de significância. Para verificar-se a ocorrência de conglomerados, foi aplicado o teste de varredura espacial, processado por meio do programa SaTScan. Demonstrou-se que 17,9% dos soros reagiram à Leptospira spp. (p<0,0001). Quanto ao manejo de criação, os cães que tinham acesso à rua (22,14%) apresentaram-se (p<0,05) como os mais reagentes, em relação aos que não o tinham (14,83%). Os resultados da estatística de varredura apontaram apenas um conglomerado significativo, influenciado pela composição etária da população em risco. Incorporando-se cada uma das co-variáveis de sexo, raça e acesso à rua, à co-variável idade, verificou-se que o fator acesso à rua foi o que mais contribuiu para explicar o conglomerado encontrado. O acesso à rua e a idade mostraram ser os fatores de risco mais importantes no excesso de animais sororreagentes, no conglomerado encontrado, sendo o sorovar castellonis o que apresentou a maior taxa nas amostras sorológicas caninas da área territorial urbana. A identificação de um conglomerado com cães sororreagentes acima do esperado permite que sejam tomadas medidas preventivas localizadas.

We aimed to evaluate the risk facto r of serum reactive dogs to antileptospire agglutinin and their spatial distribution in an urban area. We collected 1,000 blood samples from dogs at 20 immunization centers, homogeneously distributed in the urban area (32 km involution 2) of Botucatu, Sao Paulo, Brazil. Diagnosis was made by microscopic serum agglutination using 24 serovars of Leptospira spp. Statistical analysis was performed by Goodman's test with 5% of significance. Spatial clusters were tested by spatial scan statistic using SaTScan. We found that 17.9% dogs reacted to Leptospira spp. (p<0.0001). Dogs with street access (22.14%) were more reactive (p<0.05) than those without (14.83%). The scan test indicated only one significant cluster influenced by age. Incorporating each one of the co-variables gender, breed, and street access to age, we found that street access was the most important. Street access and age were the most important risk factors in the large number of reactive animaIs in the cluster, with the castellonis serovar being the most reactive in urban dogs. The identification of a cluster with more reactive dogs than expected allows local preventive measures to be taken.

The effect of anti-prolactin antibody on in vitro synthesis of a pregnancy-associated rat uterine glycoprotein.

Experiments were conducted to study the hormonal (estrogen [E2], progesterone [P4] and prolactin [PRL]), regulation of synthesis of a pregnancy-associated glycoprotein (named Uterine Agglutinin or UA) in the Day 4 post coital (p.c.) rat uterus with antibody administration and immunohistochemistry. Of the antibodies used, it was shown that anti-PRL antibody was the most effective in reducing in vitro UA synthesis. The results suggested that in vitro UA synthesis could be correlated to serum PRL levels as analyzed by radio-immunoassay. Binding studies revealed that PRL bound specifically to the stromal cells of the rat uterus where UA is produced and localized.

Characterization and biological implications of membrane lectins in tumor, lymphoid and myeloid cells.

Complex carbohydrates and sugar receptors at the surface of eukaryotic cells are involved in recognition phenomena. Membrane lectins have been characterized, using biochemical, biological and cytological methods. Their biological activities have been assessed using labeled glycoproteins or neoglycoproteins. Specific glycoproteins or neoglycoproteins have been used to inhibit their binding capacity in both in vitro and in vivo experiments. In adults, lymphoid and myeloid cells as well as tumor cells grow in a given organ and eventually migrate and home in another organ; these phenomena are known as the homing process or metastasis, respectively. In specific cases, membrane lectins of endothelial cells recognize cell surface glycoconjugates of lymphocytes or tumor cells, while membrane lectins of lymphocytes and of tumor cells recognize glycoconjugates of extracellular matrices or of non-migrating cells. Therefore, membrane lectins are involved in cell-cell recognition phenomena. Membrane lectins are also involved in endocytosis and intracellular traffic of glycoconjugates. This property has been demonstrated not only in hepatocytes, fibroblasts, macrophages and histiocytes but also in tumor cells, monocytes, thyrocytes, etc. Upon endocytosis, membrane lectins are present in endosomes, whose luminal pH rapidly decreases. In cells such as tumor cells or macrophages, endosomes fuse with lysosomes; it is therefore possible to target cytotoxic drugs or activators, by binding them to specific glycoconjugates or neoglycoproteins through a linkage specifically hydrolyzed by lysosomal enzymes. In cells such as monocytes, the delivery of glycoconjugates to lysosomes is not active; in this case, it would be preferable to use an acid-labile linkage. Cell surface membrane lectins are developmentally regulated; they are present at given stages of differentiation and of malignant transformation. Cell surface membrane lectins usually bind glycoconjugates at neutral pH but not in acidic medium: their ligand is released in acidic specialized organelles; the internalized ligand may be then delivered into lysosomes, while the membrane lectin is recycled. Some membrane lectins, however, do bind their ligand in relatively acidic medium as in the case of thyrocytes. The presence of cell surface membrane lectins which recognize specific sugar moieties opens the way to interesting applications: for instance, isolation of cell subpopulations such as human suppressor T cells, targeting of anti-tumor or anti-viral drugs, targeting of immunomodulators or biological response modifiers.