Production and characterisation of polyclonal antisera against feline IgE.

Cats, naturally or experimentally infected with Toxocara cati were immunised with dinitrophenylated ascaris antigen (DNP-Asc). All cats developed immediate skin reactivity to DNP coupled to bovine serum albumin (DNP-BSA) and the sera of the nine cats had a heat labile homocytotropic antibody detectable by homologous Prausnitz-Küstner (PK) tests. Reagin-rich fractions were prepared from these sera and used for the preparation of polyclonal antisera in rabbits. Resultant antisera were passed through a immunoabsorbent column of Sepharose 4B coupled to heated normal cat serum. An immunoabsorbent column prepared with the resultant antisera removed the PK reactivity from the cat sera, and the activity was recovered following acid elution. The antiserum failed to detect any recognised immunoglobulin in cat sera, but precipitated with a heat labile protein with gamma-1 electrophoretic mobility in the sera of parasited cats. These findings support the contention that the antisera are specific for feline IgE.

[Immunochemical structural study of syphilitic reagins]. / Izuchenie immunokhimicheskoi struktury sifiliticheskikh reaginov.

Syphilitic reagines, which are lipid-binding antibodies, were studied. A method for isolation and purification of the reagines described is based on their interaction with immobilized lipid antigen. Antibodies, studied by the immunochemical methods in several types of syphilis, are represented by various classes of immunoglobulins.

Induction and yield of reaginic antibodies in mouse serum and ascitic fluid.

Reaginic antibody in ascitic fluid was isolated from mice immunized with ovalbumin and TAl(OH)3 or with avalbumin and pertussis adjuvant. Partial purification of this reagin by ammonium sulphate precipitation, gel filtration, and ion-exchange column chromatography yielded a gammaglobulin fraction highly active in the passive cutaneous anaphylaxis reaction. This was identical in purity and specific activity to a fraction of partially purified reagin isolated from mouse antiserum. The recovery of reaginic activity after purification from ascitic fluid was 19 per cent compared to the 7-8 per cent recovery from anti-serum. These studies demonstrate that ascitic fluid in mice immunized with methods known to produce reaginic antibody provides an excellent source of mouse IgE.

Isolation and preparation of antisera to ovine IgE.

Elevated levels of ovine reaginic antibody were induced by immunization with Ascaris suum antigens. The PCA activity of this antibody persisted in the skin of sheep for 20 days and was abolished by heating to 56 degrees C, suggesting that it was immunoglobulin E. Attempts to isolate IgE from this hyperimmune serum by gel filtration, ion exchange and affinity chromatography resulted in the preparation of a PCA-positive fraction containing proteins with molecular weights of 70, 56 and 22 kD on SDS-PAGE. This preparation was used to raise an antiserum in a rabbit to IgE which was rendered specific by absorption. An antiserum to the heavy chain of ovine IgE was also raised in a rabbit by immunization with a fraction prepared from the 68- to 80-kD region of SDS-PAGE by excision and electroelution. Both antisera were positive in reverse cutaneous anaphylaxis tests and recognized a single protein with a molecular weight of 70-72 kD on SDS-PAGE immunoblotting. The presence of this protein in reaginic sheep serum, the molecular weight of its heavy chain, its heat lability and long-term skin-sensitizing ability are characteristic of IgE.