157 Effect of Sheep Breed on Neutrophil Chemotaxis to<i>Haemonchus Contortus</i> Larval Antigen

Abstract Parasite-resistant St. Croix sheep generate a potent neutrophilic response to larval stages of Haemonchus contortus. Protective neutrophil responses can be best characterized by increased infiltration the abomasum within first 3 days infection. These data indicate breed differences in chemotaxis and H. contortus The purpose this study was determine third-stage (L3) antigen (HcLA). Suffolk (SUF) (STC) neutrophils were isolated applied matrigel-coated clearview inserts, placed into reservoir containing HcLA, Interleukin-8 (IL-8), or complete media. Neutrophil plates incubated (37°C, 5% CO2) an Incucyte S3 live cell imaging system for 24 hours, measurements taken hourly. Neutrophils from STC migrated towards HcLA quicker than SUF neutrophils, migration occurred as early hours (10% 4% respectively, P &amp;lt; 0.001). difference over time, where 28% at 14 compared with 13% cells same time. By 37% while percentage migrating remained (13%). Positive control IL-8, achieved 7 26% neutrophils. IL-8 induced similar both breeds (STC 47%, 41%). Taken together, these that delayed may contribute establishment parasite-susceptible hosts. Thus, indicating infection is critical component full host protective immunity.