Described herein are methods that combine phage and yeast display to create polyclonal antibodies that are renewable, and when amplified over 100 million fold, maintain diversity without loss of representation of any of the antibodies present. The antibody representation remains essentially constant, as confirmed by deep sequencing. The provided methods allow generation, use and propagation of polyclonal antibodies, without concern that representation is lost. Furthermore, because the derivation of the polyclonal pool is carried out in vitro using phage and yeast display, it is possible in various embodiments to eliminate reactivities that are considered undesirable. Additionally, the polyclonal pool can be enriched for higher affinity antibodies.
ACKNOWLEDGMENT OF GOVERNMENT SUPPORT
 This invention was made with U.S. government support under Contract No. DE-AC52-06NA25396 awarded by the U.S. Department of Energy. The U.S. government has certain rights in the invention.