Sufficient Precipitation Solution B is supplied so that the researcher can perform this step for each preparation. Alternately, a spectrophotometric determination can be made at 280nm using 13.6 as the extinction coefficient. A single egg contains as much antibody as an average bleed from a rabbit. In addition, egg collection is simple and non-invasive. Eggs are generally laid on a daily basis, whereas a rabbit may only be bled once every 2-3 weeks.
Chickens require only a one month immunization regimen to obtain high titers of polyclonal antibody.
To ensure a rabbit is producing high titers of antibody, the immunization procedure requires up to 2-3 months. Similar amounts of antigen are required to immunize chickens and rabbits, but daily egg collection occurs over a month and titers generally remain high during this period. A rabbit may be bled only once every 2-3 weeks and the amount of antibody contained in the sera is equivalent to the amount of antibody in a single egg. Because the phylogenetic distance between birds and mammals is great, chickens are very useful for producing antibodies against conserved mammalian proteins. The Fc portion of the chicken antibody is unique and does not bind to staphylococcal protein A or streptococcal protein G, which are commonly used for immunoprecipitation protocols with mammalian antibodies.