Development of snake antivenom antibodies in chickens and their purification from yolk

Adult white leghorn hens hyperimmunised with Brazilian snake venoms of the genus Bothrops and/or Crotalus produced antibodies capable of recognising, combining with and neutralising the toxic and lethal components of the veno ms. The antibodies were first detected by an enzyme-linked immunosorbent as say two weeks after starting the immunisation schedule, reached the highest titres by the third week and remained high for at least 24 weeks, These an tibodies are transferred to the egg yolk from which they were isolated as e nriched IgY preparations by a combination of methods using positive and neg ative precipitation with sodium sulphate and/or caprylic acid. The yolk-der ived IgY preparations contained antibodies which blocked the phospholipase A(2)-dependent haemolytic activity of both venoms and the haemorrhagic acti vity of Bothrops venom, and neutralised the toxic lethal activities of the venoms with good efficacy. The median effective dose (ED50) of the IgY anti -Bothrops venom was 592 . 5 mu l/2LD(50) and, 1 . 0 ml neutralised 0 . 0675 mg of venom, The ED50 of the IgY anti-Crotalus venom was 457 . 5 mu l/3LD( 50) and 1 . 0 ml neutralised 0 . 075 mg of venom.