Bohl E H, Frederick T, Saif L J
Am J Vet Res. 1975 Mar;36(3):267-71.
Nine pregnant swine were intramuscularly injected with a modified live-virus transmissible gastroenteritis (TGE) vaccine at approximately 6 and 2 weeks before parturition. The TGE antibody levels in milk whey rapidly decreased within a few days after parturition, and the antibodies were mainly, if not solely, of the immunoglobulin G (IgG) class. Nursing newborn pigs were challenge exposed with virulent TGE virus when 2 to 4 days old. All pigs in 8 of the 9 litters became affected with typical signs of TGE. Of the pigs nursing vaccinated sows, 55% died, and of the 9 vaccinated sows, 8 became affected after challenge exposure of their litters. Subsequently, the antibody titers in serum and milk markedly increased in all 9 sows, with the antibody in milk being predominantly of the immunoglobulin A (IgA) class. Serum samples of prenursing newborn pigs from vaccinated sows did not contain detectable TGE antibodies. The capability of the vaccinated sows to provide only limited passive immunity to their suckling pigs was considered to be due mainly to the low titer and class (IgG) of TGE antibody existing in the milk of the sows at the time the newborn pigs were challenge exposed.
9头妊娠母猪在分娩前约6周和2周时肌肉注射了一种改良的活病毒传染性胃肠炎（TGE）疫苗。分娩后几天内，乳清中的TGE抗体水平迅速下降，且抗体主要（如果不是唯一的话）是免疫球蛋白G（IgG）类。哺乳的新生仔猪在2至4日龄时用强毒TGE病毒进行攻毒暴露。9窝仔猪中有8窝的所有仔猪都出现了典型的TGE症状。在哺乳接种疫苗母猪的仔猪中，55%死亡，在9头接种疫苗的母猪中，有8头在其仔猪接受攻毒暴露后受到感染。随后，所有9头母猪血清和乳汁中的抗体滴度均显著升高，乳汁中的抗体主要是免疫球蛋白A（IgA）类。来自接种疫苗母猪的哺乳前新生仔猪的血清样本中未检测到TGE抗体。接种疫苗的母猪为其哺乳仔猪提供的被动免疫力有限，这主要被认为是由于在新生仔猪接受攻毒暴露时，母猪乳汁中存在的TGE抗体滴度低且为IgG类。
