367 - Determination of Circulating Interleukin 13 in Sheep After Infection with Haemonchus Contortus

Interleukin 13 (IL-13) is a critical cytokine involved in development of Type 2 (Th2) immunity, necessary for generating full host protective response against Haemonchus contortus (Hc). St. Croix (STC) sheep have well-documented resistance, generating a robust immune response to larval stages of infection, thus preventing establishment of adults due to a rapid cellular and strong TH2 immune response. Previous studies have shown that exposing Hc L3 to recombinant-IL-13 causes a significant reduction in larval speed and distance traveled. These data, coupled with known physiological effects of IL-13 on increased gut motility, indicate that oral administration of IL-13 may have potential therapeutic benefits. Therefore, the aim of this study was to evaluate the amount of IL-13 in circulation in both STC and Suffolk (SUF) sheep to establish a proper dosage for oral administration as a therapeutic control for parasitic infections. Two contemporary groups STC (n = 14) and SUF (n = 14) were raised in an Hc-free barn for the duration of the project. Four weeks after weaning each lamb received a single oral dose of 10,000 Hc-L3. Infection persisted for 5 weeks before animals were dewormed with levamisole, and then rested for three weeks. After which, primed lambs were challenged with an additional 10,000 Hc-L3. Blood was collected daily for 14 days. Serum was removed and pooled (by breed/by day) and concentration of IL-13 was detected using an ovine specific IL-13 ELISA assay. There was a difference in the mean amount of circulating antibody between breeds STC (4.415) SUF (4.093) (P < 0.001). STC have a higher amount of circulating IL-13 and that amount may be utilized in development of future therapeutic treatments.