ABSTRACT
In this study, cellular localization and the distribution pattern of BVDV genome in lymphoid tissues during the course of experimental acute BVDV-1 infection of sheep was investigated. Tonsils, mesenteric lymph nodes (MLN) and spleen were collected on 3, 6, 9, 12 and 15 days post infection (dpi) from twenty 4-month-old lambs, experimentally inoculated intra-nasally with 5 × 10(5) TCID50 of a non-cytopathic (ncp) BVDV-1 isolate, Ind-17555. Tissues collected from ten mock-infected lambs served as controls. In situ hybridization (ISH) was carried out in paraformaldehyde fixed paraffin embedded tissue sections using digoxigenin labelled riboprobe targeting 5'-UTR of BVDV-1. BVDV genome was detected at all the intervals from 3 dpi to 15 dpi in the lymphoid tissues with variations between the intervals and also amongst the infected sheep. During the early phase of acute infection, presence of viral genome was more in tonsils than MLN and spleen, whereas the distribution was higher in MLN during later stages. BVDV-1 genome positive cells included lymphocytes, macrophages, plasma cells, reticular cells and sometimes crypt epithelial cells. Genome distribution was frequently observed in the lymphoid follicles of tonsils, MLN and spleen, besides the crypt epithelium in tonsils, paracortex and medullary sinus and cords of MLN. Most abundant and widespread distribution of BVDV-1 genome was observed on 6 dpi while there was a reduction in number and intensity of positive signals by 15 dpi in most of the infected animals. This is the first attempt made to study the localisation of BVDV-1 in lymphoid tissues of acutely infected sheep by in situ hybridization. The results show that the kinetics of BVDV-1 distribution in lymphoid tissues of experimentally infected non-pregnant sheep follows almost a similar pattern to that demonstrated in BVDV infected cattle.
Subject(s)
Diarrhea Virus 1, Bovine Viral/isolation & purification , Genome, Viral/physiology , Lymphoid Tissue/virology , Pestivirus Infections/veterinary , Animals , Diarrhea Virus 1, Bovine Viral/genetics , Diarrhea Virus 1, Bovine Viral/immunology , Genome, Viral/genetics , In Situ Hybridization/veterinary , Pestivirus Infections/immunology , Pestivirus Infections/virology , Sheep , Tissue DistributionABSTRACT
Genes coding for human leukocyte antigen (HLA) class II molecules and tumor necrosis factor (TNF)-α are polymorphic and have been shown to influence susceptibility to infectious diseases. In the present study, HLA-DRB1, -DQB1 and TNF gene polymorphisms were investigated in 114 dengue patients (DEN) [85 dengue fever (DF) cases and 29 dengue hemorrhagic fever (DHF) cases] and 110 healthy controls (HCs) using PCR based methods. The frequencies of HLA-DRB1*07 allele [DF vs. DHF, P=0.0034, Pc=0.044, OR 3.79] and HLA-DRB1*07/*15 genotype [DF vs. DHF, P=0.00071, Pc=0.038, OR 10.41] were significantly higher in DHF cases as compared to HCs and DF cases. Higher frequency of rs1800629 'G/A' genotype was observed in DHF cases as compared to DF cases. The frequency of rs1799964 'C/C' genotype of the TNF gene was found to be significantly higher in all patient groups compared to HCs [HCs vs. DEN, P=0.0054, Pc=0.0162, OR 3.57; HCs vs. DF, P=0.036, OR 2.89; HCs vs. DHF, P=0.0088, Pc=0.0240, OR 5.11]. Presence of combination of HLA-DRB1*07/*15 with either rs1799964 'C/C' genotype or rs1800629 'G/A' genotype or both was present in 17.2% of DHF cases and 1.2% in HCs while this combination was not observed in DF cases. The results suggest that HLA-DRB1*07/*15 genotype in combination with TNF polymorphisms influence progression to DHF.
