ISOLATION AND PREPARATION OF ANTISERA TO OVINE IGE

Elevated levels of ovine reaginic antibody were induced by immunizatio n with Ascaris suum antigens. The PCA activity of this antibody persis ted in the skin of sheep for 20 days and was abolished by heating to 5 6-degrees-C, suggesting that it was immunoglobulin E. Attempts to isol ate IgF; from this hyperimmune serum by gel filtration, ion exchange a nd affinity chroromatography resulted in the preparation of a PCA-posi tive fraction containing proteins with molecular weights of 70,56 and 22 kD on SDS-PAGE. This preparation was used to raise an anti-serum in a rabbit to IgE which was rendered specific by absorption. An anti-se rum to the heavy chain of ovine IgE was also raised in a rabbit by imm unization with a fraction prepared from the 68- to 80-kD region of SDS -PAGE by excision and electroelution. Both antisera were positive in r everse cutaneous anaphylaxis tests and recognized a single protein wit h a molecular weight of 70-72 kD on SDS-PAGE immunoblotting. The prese nce of this protein in reaginic sheep serum, the molecular weight of i ts heavy chain, its heat lability and long-term skin-sensitizing abili ty are characteristic of IgE.