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• Recombinant chicken IFN-α can improve the preventive effect of inactivated avian influenza H9N2 vaccine. Control of currently circulating re-assorted low-pathogenicity avian influenza (LPAI) H9N2 is a major concern for both animal and human health. Thus, an improved LPAI H9N2 vaccination strategy is needed to induce complete immunity in chickens against LPAI H9N2 virus strains. Cytokines play a crucial role in mounting both the type and extent of an immune response generated following infection with a pathogen or after vaccination. To improve the efficacy of inactivated LPAI H9N2 vaccine, prokaryotic expression recombination chicken interferon-α (rchIFN-α) was used as vaccine adjuvant.In this study chIFN-α was used as adjuvant in inactivated AI H9N2 vaccine, modulated the immune response of chickens against the vaccine antigen through enhanced humoral and Th1-biased cell-mediated immunity, compared to chickens that received single AI H9N2 vaccine. To further test the protective efficacy of this improved vaccination regimen, immunized chickens were challenged with a high dose of LPAI H9N2 virus. Combined administration rchIFN-α showed markedly enhanced protection compared to single administration of the vaccine, as determined by mortality, clinical severity, and feed and water intake. This enhancement of protective immunity was further confirmed by reduced rectal shedding and replication of AIV H9N2 in challenged chickens. Our results indicate the value of combined administration of rchIFN-α to generate an effective immunization strategy in chickens against LPAI H9N2. [ABSTRACT FROM AUTHOR] more...

• Pretreatment of rPoIFN-α before TGEV challenges can promote the survival rate of experimental piglets. • Pretreatment of rPoIFN-α before TGEV challenge can reduce TGE clinical symptoms and virus shedding in piglets. • Pretreatment of rPoIFN-α in piglets can inhibit TGEV infection in a dose-dependent manner. Our previous research obtained purified recombinant porcine interferon-α (rPoIFN-α) containing thioredoxin (Trx) fusion tag in E. coli Rosetta (DE3). Here, we evaluate the efficacy of this rPoIFN-α 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 × 10(7)IU/pig, 2 × 10(6)IU/pig, and 2 × 10(5)IU/pig rPoIFN-α 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-α 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 × 10 (7) IU/pig rPoIFN-α are fully aligned with the violent TGEV attack. Pigs pretreated with 2 × 10 (6) IU/pig rPoIFN-α are partially aligned with the violent TGEV attack. Though piglets pretreated with 2 × 10(6) IU/pig or 2 × 10(5)IU/pig rPoIFN-α cannot be adapted to the challenge of TGEV. However, the use of this dose of rPoIFN-α could put off the clinical signs of pigs than the positive control group of the above. These results indicate that rPoIFN-α can protect pigs from the infection of potential TGEV or delay the appearance of clinical symptoms, and its effect is dose-dependent. [ABSTRACT FROM AUTHOR] more...