Diagnóstico do vírus da Reticuloendoteliose Aviária por Imunohistoquímica e Hibridização In Situ

Abstract

Reticuloendotheliosis virus (REV) is a retrovirus that infects a variety of domestic and wild birds. REV infection can result in immunosuppression, runting syndrome, high mortality, or acute reticular cell neoplasia and/or T- or B-cell lymphomas. Lymphomas caused by REV resemble those associated with Avian Leucosis (AL) and Mareks disease (MD). Therefore, histopathologic differentiation of these diseases is not possible. Currently available diagnostic methods for REV do not detect active infections. In order to develop mass screening diagnostic methods for REV active infections, namely in situ hybridization (ISH) and immunohistochemistry (IHC), slides sections from experimentally inoculated 10% formalin-fixed, and paraffin embedded cultured DF-1 chicken embryo fibroblasts (DF-1 CEF), as well as tissues from experimentally infected Japanese quail embryos tissues, and archive tissues from birds with natural and experimental infections were used. ISH and IHC assays were developed using riboprobe templates (REV-APC 566) and a commercially available polyclonal avian REV antiserum, respectively. These ISH and IHC protocols were adequate to detect REV genomic sequences and antigens in cultured cells and embryo tissues experimentally inoculated. No evidence of cross reactions or labeling of cells infected with representative strains of Avian Leucosis/sarcoma group of viruses (ALV) were observed, confirming the specificity of these methods. Only one case (in a total of 10 cases) of archive paraffin embedded tissues with previous diagnosis of reticuloendotheliosis was positive by ISH and IHC, indicating lack of active infection, which can impair the sensitivity of the ISH and IHC developed in this study. In conclusion, the diagnostic assays described here, were suitable to identify active REV infections