Tumor venéreo transmissível canino - I. Expressão gênica e proteica e caracterização genotípica de DLADQA-1 (MHC-II); II. Estudo imuno-histoquímico da resposta imune local

• Ano de defesa: 2015
• Autor(a) principal: Castro, Karina Ferreira de [UNESP]
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual Paulista (Unesp)
• Palavras-chave em Português: Cães; Cancer; Doenças transmissiveis; Tumores em animais; Expressão gênica
• Link de acesso: http://hdl.handle.net/11449/136794; http://www.athena.biblioteca.unesp.br/exlibris/bd/cathedra/22-03-2016/000860377.pdf

The canine transmissible venereal tumor (CTVT) is a transmissible cancer that is spread between dogs by the allogeneic transfer of living cancer cells during coitus. It is the oldest cancer lineage known in nature and one of the most remarkable features of CTVT is its ability to develop and evade the immune rejection, as an allogeneic graft, despite the strict and continuous surveillance of the immune system. It has been hypothesized that CTVT cells do not express MHC-II as an escape mechanism to immune detection, and MHC-II positivity detected in tumor samples can be attributed to infiltrating host cell at the tumor site. The aims of this study were: evaluate gene and protein expression and genotypic characterization of DLADQA-1 locus (MHC-II) in spontaneous transmissible venereal tumours in dogs. Additionally, to detect the interaction between serum antibodies and specific tumor antigens of CTVT. For this, 20 dogs from São José do Rio Preto, São Paulo, Brazil with naturally occurring CTVT were included and samples were collected before chemotherapy (M1) and three weeks after starting chemotherapy (M2). The gene expression analysis was performed by qPCR method and protein expression of CD3, CD79, MAC387, Ki67 and MHC-II by immunohistochemistry method. Sequencing was performed by capillary method and the study of tumor antigens by the Western Blotting technique. CTVT samples and their hosts from other countries have been used for comparative studies. Significant differences were observed in MHC-II and CD3 immunostained cells between M1 and M2 with higher expression in M2. There was no gene expression of DLADQA-1 in any sample of CTVT in M1 and M2. The genotypic similarity between tumor samples, which differ from their respective hosts, is consistent with a clonal origin of this tumour. There was no significant difference between the genotypes of hosts and control dogs. The detection of two protein bands in different CTVT from Brazil ...