Mapping quantitative trait loci for stress induced alterations in porcine leukocyte numbers and functions

To identify quantitative trait loci (QTLs) with effects on 'stress' induced alterations of porcine immune functions, a number of immune capacity trait s were analysed in the F-2 generation of a Wild Boar - Yorkshire intercross . All traits were measured prior, and one day after, exposure to experiment al 'stress' (mixing and transport). The 'stress' protocol induced a decreas e in numbers of circulating neutrophils and in spontaneous proliferation in vitro, whereas phagocytic capacity, mitogen induced proliferation and spon taneous IL-2 activity increased. The IFN-alpha production tended to decreas e, although the individual variation was pronounced. More than 200 genetic markers have been scored in the entire pedigree and were used to trace the inheritance of individual chromosome segments. Wild Boar alleles were on av erage associated with higher mitogen induced IL-2 activity and a slightly l ower decrease in IFN-alpha production after mixing and transport. Four QTLs with significant effects were identified; one influencing 'stress' induced alteration in numbers of neutrophils (chromosome 8), one influencing spont aneous proliferation after 'stress' (chromosome 2), one influencing mitogen induced IL-2 activity after 'stress' (chromosome 6) and one influencing 's tress' induced alterations in mitogen induced IL-2 activity (chromosome 12) . In addition, several suggestive QTLs were indicated.