Characteristics Studies Of Porcine Transmissible Gastroenteritis Virus Vaccine Producing Seeds

Transmissible gastroenteritis of pigs (TGE) is caused by transmissible gastroenteritis virus (TGEV), an acute and highly contact of pig gastrointestinal infectious disease. Transmissible gastroenteritis virus belongs to the family of coronavirus, which can cause the symptom such as fever, vomiting, severe diarrhea and dehydration. Especially within 2 weeks of piglet mortality can be as high as 100%, its cause huge economic losses. At present vaccination is the most effective way to prevent the disease. Preparation of stable, clean, reliable and safe vaccine producing seeds can lay a foundation for vaccine research and development.In this research, The virulence determination, RT-PCR identification, thermal stability test, pH3.0 value stability test, chloroform sensitivity test,Pure characteristics identification were developed with transmissible gastroenteritis virus (TGEV) SC-T strain seed virus, which was saved and separated by our laboratory. The results of RT-PCR identification show that the Objective gene stripe size is the same as anticipated objective strap size and Objective gene sequencing results were in conformity with TGEV gene sequences. Thermal stability test, pH3.0 value stability test, chloroform sensitivity test showed that the seed virus is sensitive to temperature, below 50℃ seed virus activity were stable. The pH3.0 is not sensitive to the virus titer. The virus seed is sensitive to chloroform. TGEV SC-T Strain seed virus were continuous cultured to 30th generations in the pure and grow well swine testicular generations cells (ST cells). Selecting ten generations seeds with high and stable virus virulence for the foundation seed batch and production seed batch. The virulence determination, safety test, immunogenicity test, specific identification, pure characteristics identification were developed with the foundation seed batch and production seed batch. Virulence determination showed that:the transmissible gastroenteritis virus (TGEV) SC-T strain seeds from 10 generations to 20 generations, its virus titer were stable and all above 106.0 TCID50/ml. Safety testing showed that the immune piglets and contrast piglets all are not have fever, anorexia, depression and other clinical symptoms. Immunogenicity test showed that the immune piglets with transmissible gastroenteritis virus virulent strain attacked, its body temperature slightly elevated and all immune piglets were healthy survival, control piglets with virulent strain attacked, were depression, anorexia and even waste off, difficulty breathing, and three piglets died for the end-all. Specific identification showed that normal cells bores and virus neutralization bores do not showed cytopathic effect (CPE), the virus control group showed CPE. Pure characteristics identification showed that each generation seeds were not contaminated by bacteria, mold, adventitious virus and mycoplasma.The above experimental results show that the transmissible gastroenteritis virus (TGEV) SC-T strain seed virus and swine testicular generations cells (ST cells) could satisfy the requirement for preparing vaccine. The each generation seed of transmissible gastroenteritis virus SC-T strain seeds can stably generations on ST cell, the virus titer of the foundation seeds and production seeds are high and stable, the virus has a good safety, immunogenicity, specificity, and the purity characteristics. The foundation seed batch and production seed batch conform to the provisions of China Veterinary Pharmacopoeia, China Veterinary Biological Products Quality Standards. And the consequences were the base of further clinical trials and vaccine development.