Identification of ovine innate and adaptive immunity loci involved in the pathogénesis of two diseases with retroviral aethiology, ovine pulmonary adenocarcinoma and maedi-visna
- Autores: Amaia Larruskain Mandiola
- Directores de la Tesis: Begoña M. Jugo (dir. tes.)
- Lectura: En la Universidad del País Vasco - Euskal Herriko Unibertsitatea ( España ) en 2012
- Idioma: español
- Tribunal Calificador de la Tesis: Ana María Zubiaga Elordieta (presid.), Jose Antonio Rodríguez Pérez (secret.), Jesus Emilio de Albornoz Pons (voc.), M. Amills (voc.), Damián Fermín de Andrés Cara (voc.)
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- Resumen
Ovine Pulmonary Adenocarcinoma (OPA) and Maedi-Visna (MV) are diseases caused by retro¬viruses of the Betaretrovirus (Jaagsiekte Sheep Retrovirus - JSRV) and Lentivirus (Maedi-Visna virus -MVV) genera, respectively. OPA is a contagious lung cancer while MV is a progressive lymphoprolifera¬tive disease that may affect several organs. Both are widespread chronic illnesses of sheep which are invariably fatal once clinical disease develops. In both cases, young adult sheep are mostly affected leading to economic losses through decrease in production and early culling. In addition, they pose a welfare concern due to lack of treatment or effective vaccines. Few works have analysed the involvement of the host¿s immune response genes in these dis¬eases. This work was conducted to identify associations between genetic markers located in immune-relevant loci and Resistance/Susceptibility to OPA and MV clinical disease progression and Resistance/ Susceptibility to MVV infection. Candidate genes selected for genotyping were genes of the innate and adaptive immunities, including markers in the Major Histocompatibility region (MHC), Interleukins and loci of the innate immune response involved in the recognition of viral components and antiviral defence. Samples were obtained from three sheep breeds, Latxa, Assaf and Rasa Aragonesa. Animals recruited for the clinical disease analysis were screened post-mortem for OPA- and MV-characteristic lesions in target organs. Moreover, the MVV infection status (Seropositive/Seronegative) of a sample of Latxa individuals was tested longitudinally over an approximate 3-year period by ELISA tests. Several types of markers were employed in this work, namely microsatellites, SNPs, haplotypes (both directly typed in the laboratory by PCR-SBT and bioinformatically inferred with PHASE v.2.1.) and quantitative analysis of candidate loci expression. Concerning the association studies, statistical tools were adapted to the characteristics of each sample and marker. All analyses were adjusted for potential confounding factors such as genetic structuration, age, flock or elevated marker polymorphism when applicable. Statistical analyses were conducted with the softwares SAS v.9.0., R v.2.7.0. and REST 2009. Significant associations were identified between some of the typed markers and the pathogenesis of OPA and MV, including MHC loci (Class I and II), cytokines and genes of the innate immunity. For OPA, MHC Class II alleles DRB1*0143 and *0323 were susceptible and allele *0702 resistant to disease progression. The latter stood out in the motif-based analysis as well, which would give the analysis a functional perspective. The microsatellite-based analysis of the MHC associated Class I allele OMHC1*193 with OPA susceptibility, as well as an haplotype containing this allele. Moreover, the allelic, genotypic and haplotypic logistic regression analyses showed that polymorphisms in the IFN¿, IL2, IL4 IL12, TLR3 and TLR4 may influence OPA disease progression, but did not remain significant after Bonferroni correction; however, genes CCR5 and MX1 remained significantly associated with resistance and susceptibility, respectively. MHC markers were found to be involved in MV as well. Allele DRB1*0325 was significantly associated with susceptibility. In addition, microsatellites located in the MHC implicated both the Class I and II regions with susceptibility to MV disease, as alleles OMHC1*205 and DRB2*275 had signifi¬cant associations. The allelic, genotypic and haplotypic logistic regression analyses showed that IL10 was associated with susceptibility in both MVV infection and MV disease progression; moreover, TLR7 was implicated in MV resistance and CCR5 alleles were associated with susceptibility or resistance. In addition, qPCR-based expression analysis revealed that in the lungs of diseased animals candidate genes IL2 and TNF¿ were down regulated while CCR5, TLR7, TLR8 and SP-A were up regulated.
