Progress in genetically engineered vaccines for porcine transmissible gastroenteritis virus

Porcine transmissible gastroenteritis, caused by the transmissible gastroenteritis virus (TGEV), is a highly infectious, acute intestinal disease which spreads rapidly through a whole group of pigs within a few days and subsides after a week. Compared with traditional vaccines, particularly the inactivated combined TGE/PED (porcine epidemic diarrhoea) vaccine, genetically engineered TGEV vaccines such as recombinant live vector vaccines using baculoviruses, poxvirus, adenovirus, attenuated Salmonella typhimurium or lactobacillus as vectors. DNA vaccine vectors, RNA replicon vaccines, viral infectious clone vaccines, synthetic peptide vaccines and transgenic plant vaccines in which the S gene containing the major antigenic sites was inserted, eventually punctually deleted or directly expressed by the host cells, significantly improve immunogenicity, offer sufficient safety and potential for widespread application and also lower the production costs.