Inhibitory effects of recombinant porcine interferon-α on porcine transmissible gastroenteritis virus infections in TGEV-seronegative piglets

Our previous research obtained purified recombinant porcine interferon-alpha (rPoIFN-alpha) containing thioredoxin (Trx) fusion tag in E. coli Rosetta (DE3). Here, we evaluate the efficacy of this rPoIFN-alpha to prevent piglets from the infection of the transmissible gastroenteritis virus (TGEV) attack. In this experiment, twenty-five TGEV-seronegative piglets were randomly divided into five groups. Group 1 was positive control and only challenged with TGEV; Pigs in groups 2-4 were pretreated with 2 x 10(7)IU/pig, 2 x 10(6)IU/pig, and 2 x 10(5)IU/pig rPoIFN-alpha before TGEV challenge. The fifth group is a negative control group. The animals of this group are pretreated only with Trx protein-containing PBS solution without TGEV challenge. After 48 h of rPoIFN-alpha pretreatment, the pigs in groups 1-4 were challenged by TGEV, and the pigs in group 5 were administered with PBS. The surveillance results show that Pigs pre-treated with 2 x 10 (7) IU/pig rPoIFN-alpha are fully aligned with the violent TGEV attack. Pigs pretreated with 2 x 10 (6) IU/pig rPoIFN-a are partially aligned with the violent TGEV attack. Though piglets pretreated with 2 x 10(6) IU/pig or 2 x 10(5)IU/pig rPoIFN-alpha cannot be adapted to the challenge of TGEV. However, the use of this dose of rPoIFN-alpha could put off the clinical signs of pigs than the positive control group of the above. These results indicate that rPoIFN-alpha can protect pigs from the infection of potential TGEV or delay the appearance of clinical symptoms, and its effect is dose-dependent.