Lactogenic immunity to transmissible gastroenteritis (TGE) of swine induced by the attenuated Nouzilly strain of TGE virus: passive protection of piglets and detection of serum and milk antibody classes by ELISA.

Piglets of eight sows vaccinated by different routes with the attenuated TGE mutant coronavirus, Nouzilly (N) strain, and piglets from two field seropositive sows were challenged with a virulent TGE strain. On the day of challenge and 10 days after challenge, milk and serum samples from sows were analysed for their level of neutralizing antibodies, total immunoglobulin classes and TGE antibody classes by an ELISA. No direct relationship was seen between the level of protection of the litters and the titres of the different antibody classes on the day of challenge. However, an inverse correlation was seen 10 days after challenge between protection and the level of TGE antibodies.