Association of Ovar-DRB1 alleles with innate immune responses in sheep.

BACKGROUND: Major histocompatibility complex (MHC) is the best characterised genetic region associated with adaptive immune responses, including humoral and cell-mediated immunities. OBJECTIVES: In this study, the association of MHC class II alleles with inflammatory cytokines and acute-phase proteins was evaluated in sheep population. METHODS: Allelic diversity of second exon of ovine DRB1 locus (Ovar-DRB1.2) was determined in 100 indigenous Iranian Lori-Bakhtiari fat-tailed sheep using restriction fragment length polymorphism and direct sequencing methods. The association of DRB1.2 alleles with inflammatory cytokines (interleukin-1ß, IL-1ß; IL-6 and tumour necrosis factor-α) and acute-phase proteins (serum amyloid A, alpha-1-acid glycoprotein and haptoglobin) was examined using generalised linear model and multivariate regression analysis. RESULTS: Seven distinct RsaI restriction patterns and fourteen alleles were identified in this population. Allele DRB1*2101 showed a negative influence on the IL-6 response and was associated with lower serum level of IL-6. DRB1.2 heterozygous individuals also showed higher haptoglobin concentration than homozygotes. CONCLUSIONS: These results provide additional support for the association between Ovar-DRB1 alleles and regulation of immune responses in sheep population. Description of MHC polymorphism and its role in the controlling of immune responses will increase our understanding of host-pathogen interactions, and ultimately facilitate the selection of disease-resistant flocks in genetic breeding programs.

Production, purification, and evaluation of quail immunoglobulin Y against Salmonella typhimurium and Salmonella enteritidis.

Salmonella species have been the major foodborne problems in food production systems, with Salmonella enterica serovars typhimurium (S. typhimurium) and enteritidis (S. enteritidis) being among the more common isolates. The oral administration of chicken egg yolk specific antibodies (IgYs) has been established as an efficient alternative for treatment and prevention of gastrointestinal pathogens including Salmonella. The present study was aimed to investigate the possible production of specific IgYs against Salmonella typhimurium and Salmonella enteritidis in quail egg yolks. Salmonella spp.-free female Japanese quails (Coturnix coturnix japonica) were intramuscularly immunized with formalin or heat-inactivated Salmonella immunogens (1.0 × 109 CFU/mL) emulsified with Freund adjuvants. Egg yolk IgYs were purified using ammonium sulfate precipitation method. Anti-Salmonella IgYs titer and specificity were determined using enzyme-linked immunosorbent assay (ELISA) and western blot analysis. Salmonella specific IgYs detected in the immunized quails were significantly higher than those of the control group, which confirmed the immunization procedure. Specific IgYs against S. typhimurium and S. enteritidis were identified in both groups immunized with heat or formalin-inactivated immunogens. However, formalin-inactivated immunogens induced relatively higher immune responses over the heat-inactivated ones. Quail anti-Salmonella IgYs showed a high specificity to their corresponding immunogens, with moderate cross-reactivity to other members of Enterobacteriaceae family. Quail can be regarded as a valuable and inexpensive source for producing large-scale of specific antibodies that can be used for immunodiagnostic and immunotherapeutic purposes.