Expressão tecidual e reconhecimento imune da paramiosina do carrapato Rhipicephalus (Boophilus) microplus

• Autor(a) principal: Leal, Bruna Ferreira
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da PUC_RS
• Texto Completo: http://tede2.pucrs.br/tede2/handle/tede/5450
• topic: BIOLOGIA; SISTEMA IMUNOLÓGICO; MICROBIOLOGIA; PARASITOLOGIA; CNPQ::CIENCIAS BIOLOGICAS::BIOLOGIA GERAL

Rhipicephalus microplus is a tick that parasite bovines, damaging the milk and meat production, and constituting a vector for agents of various diseases. R. microplus cause serious losses in countries that depend on cattle production, and the control methods used are based on the use of acaricides, which present high cost and contaminate milk and meat, generating impacts on the environment. Therefore, new methods of control, as vaccines, have been suggested. Anti-parasite protective antigens can be divided into two groups: exposed, which interact with host immune system, and concealed, that do not interact with host immune system. Paramyosin (PRM) is a protein present in invertebrates primarily characterized by muscle function, but in various parasites it has been localized in nonmuscle regions, suggesting that it may also perform functions involved in the evasion of the host immune system. The Taenia solium paramyosin inhibits in vitro the classical pathway of complement system by binding to C1, and R. microplus paramyosin (RmPRM) has been shown to bind immunoglobulins. This study aimed to evaluate the recognition of RmPRM by the sera of animals infected with R. microplus and determine the levels of paramyosin gene expression in tissues and different developmental stages of the tick, as well as to analyze the anti-complement activity of the recombinant protein. The results showed that sera from naturally infected Bos indicus and B. taurus were able to recognize the recombinant PRM. Antibodies levels found among the bovines have considerable variation, but with higher titers predominating among B. indicus individuals. The RmPRM gene transcription was detected in most tissues, organs, eggs and larvae tested, with higher levels of expression found in the fat body, an organ without muscle tissue prominence. Furthermore, this study shows that RmPRM is able to inhibit the complement system, indicating that that this protein should be an important component for the parasite survival, possibly involved in modulation of the host immune system. Corroborating other studies in parasites, these results suggest that RmPRM performs other functions than those classically described in the musculature.