Restriction fragment length polymorphism of DQB and DRB class II genes of the ovine major histocompatibility complex

The ovine major histocompatibility complex (MhcOvar) class II region was investigated by Southern blot hybridizations using ovine probes specific for the second exons of Ovar-DRB and Ovar-DQB genes. Multiple bands were revealed when genomic DNA was digested with each of five restriction enzymes (BamHI, EcoRI, HindIII, PvuII and TaqI), and successively hybridized with the two radiolabelled ovine probes. Restriction fragment length polymorphisms (RFLPs) were analysed in 89 sheep originating from six inbred families and the inheritance of the fragment patterns was determined. Forty-one fragments were recorded with the DQB probe; 32 were detected with the DRB probe. They constituted 9 DQB and 10 DRB allelic patterns. Twelve DQB-DRB haplotypes were resolved in this study.

Effects of selenium status on bovine mononuclear cell function

The effects of selenium (Se) status on the distribution and functional capabilities of bovine peripheral blood mononuclear cells (PBMC) were examined. No differences in proliferative responses to mitogens, interleukin (IL)-2 production, IL-2 receptor expression, or lymphocyte trafficking patterns were observed between PBMC from dairy cows maintained on Se adequate or Se deficient diets. In contrast, Se deficiency significantly reduced the numbers of circulating monocytes when compared to cows fed a Se adequate diet. Differences in the number of circulating monocytes had no apparent effect on the accessary functions of these cells with respect to antigen presentation and IL-2 production. These results suggest that the effect of Se-modified diets on bovine defense mechanisms is not mediated by the ability of peripheral blood lymphocytes to respond to antigen and mature into immunocompetent cells.