Purification of Prospective Vaccine Antigens from Gram-Positive Pathogens by Immunoprecipitation.

Immunoprecipitation is an affinity purification technique that exploits the highly specific interactions formed between antibodies and their cognate antigens to purify molecules of interest from complex biological solutions. The generation of an effective humoral response provides protection against a wide range of gram-positive pathogens, and thus immunoprecipitation using antibodies purified from immune humans or animals provides a simple but effective means of isolating prospective vaccine antigens from fractionated bacterial cells for downstream identification. The commercial availability of antibody preparations from donated human plasma, containing antibodies against many common gram-positive pathogens, allows the protocol to be performed in the absence of bespoke vaccination experiments. Thus, immunoprecipitation has the potential to reduce the number of animals used in vaccine studies by allowing an initial screen for promising antigens to be conducted in vitro.