Age-Related Changes Following in vitro Stimulation with Rhodococcus equi of Peripheral Blood Leukocytes from Neonatal Foals. Equus caballus

The objectives of this study were 2-fold: 1) to compare the expression profiles at specific ages of blood leukocytes from foals stimulated with virulent R. equi with those of unstimulated leukocytes; and, 2) to characterize the age-related changes in the gene expression profile associated with blood leukocytes in response to stimulation with virulent R. equi. Overall design: Peripheral blood leukocytes were obtained from 6 foals within 24 hours (h) of birth (day 1) and 2, 4, and 8 weeks after birth. The samples were split, such that half were stimulated with live virulent R. equi, and the other half served as unstimulated control. For one hyb design: we hybridized 6 samples stimulated and 6 unstimulated at each time point (30 mL of blood was treated with live virulent R. equi (Strain ATCC 33701) and the remaining 30 mL of blood with PBS ). For time course: 6 samples from day1 stimulated hybridized to week2 stimulated; day1 stimulated hyb to week 4 stimulated and day1 stimulated hyb to week8 stimulated. RNA was extracted and the generated cDNA was labeled with fluorescent dyes for microarray hybridizations using an equine microarray.