The production and characterization of anti-bothropic and anti-crotalic IgY antibodies in laying hens: A long term experiment Fábio Goulart de Andrade a, b, * , Silas Fernandes Eto a , Ana Carolina Navarro dos Santos Ferraro a , Denise Turini Gonzales Marioto a , Narciso Júnior Vieira a , Ana Paula Cheirubim a , Solange de Paula Ramos b , Emerson José Venâncio a a Laboratório de Imunologia, Departamento de Ciências Patológicas, Centro de Ciências Biológicas, Universidade Estadual de Londrina, P.O. Box 6001, CEP 86051-980, Londrina, PR, Brazil b Departamento de Histologia, Universidade Estadual de Londrina, P.O. Box 6001, CEP 86051-980, Londrina, PR, Brazil article info Article history: Received 19 September 2012 Received in revised form 24 January 2013 Accepted 29 January 2013 Available online 14 February 2013 Keywords: Antivenin IgY Yolk Snake venom Laying hen Avidity abstract Ophidian accidents represent a great public health problem in developing countries. Recent studies have shown that antibodies produced in laying hens could be an alternative method for producing antivenin in mammals. In this study we analyzed the production of IgY antibodies in laying hens inoculated with snake venom from the Bothrops and Crotalus genera over a 360-day period. IgY antibodies present in the serum and egg yolks were analyzed according to avidity, antigen recognition pattern and efficiency in neutralizing the venom. The levels of anti-bothropic and anti-crotalic IgY antibodies increased signif- icantly after the third immunization, and remained at these levels until the end of the experiment. Significantly high avidity levels were observed for anti-bothropic IgY anti- bodies on the 142nd day and for anti-crotalic antibodies on the 232nd day after the first immunization. Anti-bothropic IgY antibodies recognized antigens with molecular masses ranging from 25 kDa to 50 kDa, whereas anti-crotalic IgY antibodies mainly recognized antigens with molecular masses of 14 kDa and 30 kDa. An increase in the antigens recognized by the antivenins was observed during the experimental period. Samples of bothropic IgY antivenin antibodies presented an efficiency of 290 ml/3 DL 50 , a potency of 0.307 mg/ml and a specific activity of 0.230. Samples of anti-crotalic IgY antibodies pre- sented an efficiency of 246 ml/4 DL 50 , a potency of 0.829 mg/ml and a specific activity of 0.271. These results show that the administration of successive doses of the venoms for more than 6 months results in an antivenin with higher avidity that is able to recognize a greater number of antigens present in the venoms. These characteristics indicate a more efficient and potent antivenin than what has been described in other studies. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction Ophidian accidents represent a serious public health problem in tropical countries, where they cause many deaths (Pinho et al., 2004; Williams et al., 2010). In South America, the main species responsible for these accidents are from the Bothrops and Crotalus genera (Georgieva et al., * Corresponding author. Departamento de Histologia, Universidade Estadual de Londrina, P.O. Box 6001, CEP 86051-980, Londrina, PR, Brazil. Tel./fax: þ55 4333714327. E-mail addresses: fgandrade@uel.br, fgandrade@gmail.com (F.G. de Andrade). Contents lists available at SciVerse ScienceDirect Toxicon journal homepage: www.elsevier.com/locate/toxicon 0041-0101/$ – see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.toxicon.2013.01.018 Toxicon 66 (2013) 18–24