Vaccine potential of a tick vitellin-degrading enzyme (VTDCE)

VTDCE (Vitelin-Degrading Cysteine Endopeptidase) is a peptidase with an active role in Rhipicephalus (Boophilus) microplus embryogenesis. VTDCE is found in the tick's eggs and was shown to be the most active protein in vitellin (VT) hydrolysis of the three peptidases already characterized in R. microplus eggs (Boophilus Yolk pro-cathepsin (BYC), Tick Heme Binding Aspartic Proteinase (THAP) and VTDCE). VTDCE activity was assessed in vitro using the natural substrate and a synthetic substrate (N-Cbz-Phe-Arg-MCA). The activity was inhibited by anti-VTDCE antibodies. In the present study, it was shown that VTDCE acts differently from BYC and THAP in VT hydrolysis and that the vaccination of bovines with VTDCE induces a partial protective immune response against R. microplus infestation. Immunized bovines challenged with R. microplus larvae presented an overall protection of 21%, and a reduction in the weight of fertile eggs of 17.6% was observed. The data obtained indicate that VTDCE seems to be important for tick physiology, and that it induces partial protective immune response when inoculated in bovines. This suggests that VTDCE can be useful to improve the protective capacity observed for other antigens.

Vaccination of bovines with recombinant Boophilus Yolk pro-Cathepsin

Boophilus Yolk pro-Cathepsin (BYC) is an aspartic proteinase found in Boophilus microplus eggs that is involved in the embryogenesis and has been tested as antigen to compose an anti-tick vaccine. The vaccine potential of a recombinant BYC expressed in Escherichia coli (rBYC) was investigated. rBYC was purified and used to immunize Hereford cattle. The sera of bovines immunized with rBYC recognized the native BYC with a titer ranging from 125 to 4000. Furthermore, immunized bovines challenged with 20,000 larvae presented an overall protection of 25.24%. The partial protection obtained against B. microplus infestation with the recombinant protein immunization was similar to the already described for native BYC immunization.

Purification and antigenicity of two recombinant forms of Boophilus microplus yolk pro-cathepsin expressed in inclusion bodies

The tick Boophilus microplus is a bovine ectoparasite present in tropical and subtropical areas of the world and the use of vaccines is a promising method for tick control. BYC is an aspartic proteinase found in eggs that is involved in the embryogenesis of B. microplus and was proposed as an important antigen in the development of an anti-tick vaccine. The cDNA of BYC was amplified by PCR and cloned for expression in two forms with and without thioredoxin fusion protein (Trx), coding recombinant proteins named rBYC-Trx and rBYC, respectively. Expression, solubility, and yields of the two forms were analyzed. The recombinant proteins were expressed in inclusion bodies (IBs) and three denaturant agents (N-lauroyl sarcosine, guanidine hydrochloride, and urea) were tested for IBs solubilization. The N-lauroyl sarcosine solubilized 90.4 and 92.4% of rBYC-Trx and rBYC IBs, respectively, and was the most efficient denaturant. Two recombinant forms were affinity-purified by Ni2+-Sepharose under denaturing conditions. After dialysis, the yield of soluble protein was 84.1% for r-BYC-Trx and 5.9% for rBYC. These proteins were immune-reactive against sera from rabbit, mouse, and bovine previously immunized with native BYC, which confirms the antigenicity of the recombinant BYCs expressed in the Escherichia coli system.

Three types of immunotherapics against pythiosis insidiosi developed and evaluated

Pythiosis is a granulomatous disease of horses, cattle, dogs, cats and humans identified in tropical and subtropical areas and caused by Pythium insidiosum, a zoosporic fungus. Experimental models of pythiosis in naturally infected species have not yet been reported but, rabbits may be inoculated with zoospores as an experimental model for studying the disease. The present study evaluates the efficacy of three different of immunotherapics in the rabbit model. Approximately 17500 zoospores of oomycete P. insidiosum (CBS 101555 strain) were inoculated in each animal to generate the disease. Immunotherapics were produced from vortexed or sonicated cultures of the same strain. Four groups of five animals were employed: group 1, placebo; group 2, sonicated immunotherapic; group 3, mixed immunotherapic; and group 4, vortexed immunotherapic. All rabbits were inoculated with viable zoospores one month before administration of the immunotherapics. Eight doses of immunotherapic or placebo were used in each animal with a 14 day interval between injections. Rabbits receiving the vortexed immunotherapic were most effectively protected (P<0.05), showing a decrease in the area of coastal nodules due to Pythiosis insidiosum by 71.8% after 26 weeks of evaluation. Moreover, two animals in this group showed complete remission of the infection at the end of the 26 weeks. In contrast to these findings, rabbits given the sonicated immunotherapic did not show any protection and had an increase of 211.8% in the size of lesions. This failure of sonicated immunotherapic may reflect denaturation of protective antigens due to the sonication method.

Agalactia in mares fed with grain contaminated with Claviceps purpurea

This article reports an outbreak of intoxication of female horses with Claviceps purpurea in southern Brazil. The outbreak affected twelve pregnant mares which were fed with black oat (Avena strigosa) during the pre-delivery period. Underdevelopment of the mammary gland in the pre-delivery period resulting in post-delivery agalactia was the most pronounced finding. These mares delivered weak and unviable foals, which showed no suckling reflex and died within a few hours of birth. Laboratory analysis of oat samples fed to the animals resulted in the identification of Claviceps purpurea sclerotia. The fungus was identified in 0.22% of the examined seeds.

Pitiose eqüina no Pantanal brasileiro: aspectos clínico-patológicos de casos típicos e atípicos

A pitiose eqüina é doença endêmica no Pantanal Brasileiro e causa prejuízos significativos a eqüinocultura. Neste trabalho são relatados 16 casos de pitiose subcutânea em eqüinos no Pantanal Sul-Matogrossense, que foram divididos em onze casos típicos e cinco casos atípicos, de acordo com o quadro clínico e o tempo de duração das lesões. O diagnóstico foi confirmado pela detecção de anticorpos específicos pelo teste ELISA, isolamento do agente e histopato-lógico. A duração da doença variou entre 1 e 6 meses nos casos típicos e superior a 12 meses nos casos atípicos. As lesões dos casos típicos caracterizavam-se por granulomas subcutâneos, ulcerados, com abundante secreção serossangui-nolenta e prurido. Nos casos atípicos foram observadas lesões subcutâneas caracterizadas por grandes massas "tumorais" circunscritas, recobertas por pele escura, sem ulcerações e com pouca secreção. Os animais estavam em bom estado nutricional e as lesões apresentavam-se de aspecto organizado, às vezes pedunculadas. Histologicamente, foi observado tecido de granulação com muitos eosinófilos nos casos típicos, enquanto os atípicos, se caracterizaram por hiperplasia pseudo-epiteliomatosa da epiderme e infiltrado eosinofílico. As características clínicas e histopato-lógicas completas das duas formas clínicas e os possíveis fatores responsáveis pelas diferenças entre as duas formas são apresentados e discutidos.

Cutaneous Pythiosis insidiosi in calves from the Pantanal region of Brazil

Two cases of cutaneous Pythiosis insidiosi were diagnosed in cattle from the Pantanal region, Brazil. The lesions were observed in the limbs of two 8-month-old beef calves. Close examination showed local swelling and focal ulceration of the skin. Microscopically, there was multifocal granulomatous dermatitis with intralesional Pythium insidivosum hyphae. The diagnosis was based on the morphological aspects, immunohistochemical findings and culture of the etiologic agent.