PRODUCTION OF A MONOCLONAL-ANTIBODY SPECIFIC FOR OVINE IMMUNOGLOBULIN-E AND ITS APPLICATION TO MONITOR SERUM IGE RESPONSES TO HAEMONCHUS-CONTORTUS INFECTION

Part of the C epsilon 3-C epsilon 4 region of the ovine immunoglobulin E (IgE) gene (nucleotides 1111-1575) was amplified by PCR. The recomb inant protein (recIgE1-2) was expressed in E. coli and both monoclonal and polyclonal antibodies were produced. These antibodies recognized recIgE1-2 and native IgE on Western blots and in ELISA. The polyclonal serum showed cross-reactivity with other sheep immunoglobulin classes . The monoclonal antibody was specific for ovine IgE and goat IgE. Inf ection of sheep with the abomasal nematode Haemonchus contortus result ed in elevated IgE levels in serum 2-4 weeks after infection, as measu red by sandwich ELISA using the rabbit polyclonal as capture antibody and the monoclonal antibody against ovine IgE as second antibody. A ne gative correlation between worm counts and total serum IgE levels at t he end of the experiment was found in repeatedly infected sheep. Signi ficant increased levels of excretory-secretory antigens specific IgE l evels were found after H. contortus infection. In contrast, no signifi cant changes in 3rd-stage larvae (L3) antigen-specific IgE titre in se ra could be detected after infection.