RECOGNITION OF LOW-MOLECULAR-WEIGHT COOPERIA-ONCOPHORA ANTIGENS AFTERPRIMARY AND TRICKLE INFECTION OF CALVES WITH 3RD-STAGE INFECTIVE LARVAE

Recognition of low molecular protein fragments of adult Cooperia oncop hora a of calves was studied using sera obtained after a single oral ( primary) infection with 100,000 infective 3rd-stage C. oncophora larva e, and after a 10-week period of trickle infection with moderate doses of these larvae. SDS-gel electrophoresis under reducing conditions, f ollowed by western blotting, revealed that a complex of 14-16 kDa prot ein fragments, a 27 kDa and a 31.6 kDa band of Cooperia oncophora adul t antigen were recognized by sera from calves both after primary and t rickle infection. A 19 kDa and 30 kDa protein fragment were additional ly bound by sera from calves after trickle infection. The data suggest that the systemic humoral immune response of calves to Cooperia oncop hora after trickle infection is more pronounced (14-16, 27, 31.6 kDa) and extended (19, 30 kDa) than after primary infection with Cooperia. Copyright (C) 1996 Australian Society for Parasitology, Published by E lsevier Science Ltd.