Recombinant bovine interferon alpha (rBoIFN-α) has been demonstrated to have antiviral activity. However, no conduct of acute or chronic toxicity tests has been reported. Specific pathogen-free Sprague Dawley rats were administered doses at different concentrations through intraperitoneal or intravenous injection. After the administration (single for an acute toxicity test over 14 days or daily for a sub-chronic toxicity test over 30 days), the rats’ behaviour and other indicators and the degree of toxic reaction were continuously monitored. Blood was collected for haematological and serum biochemical examinations. At the end of the experiments, the rats were sacrificed for necropsy and histopathological tissue analysis. The external performance, behaviour characteristics, and changes in body temperature and body weight of the rats in each subgroup were comparable to the normal control subgroup. Except for a few cases, there were no lesions in the viscera’s pathological structures, and the blood parameters and biochemical indicators were not noticeably different from those of the control subgroup. This study suggests that rBoIFN-α seems to be safe for rats, and its use may foster the development of the cattle industry in China by protecting livestock health.

Ovine interferon-tau (oIFN-τ) is a newly discovered type I interferon. This study used biochemical techniques to transform the oIFN-τ gene into Escherichia coli to obtain the mass and soluble expression of the recombinant protein. First, total RNA was extracted from fresh sheep embryonic tissues with TRIzol reagent and then used as a template to reverse transcribe and amplify the mature oIFN-τ gene with RT-PCR. The amplified product was next digested with the HindIII and XhoI restriction enzymes and inserted into the pET-32a(+) vector to construct the prokaryotic expression plasmid. The corrected in-frame recombinant plasmid, pET-32a(+)-oIFN-τ, was transformed into E. coli Rosetta (DE3) competent cells. After induction with isopropyl-beta-D-thiogalactopyranoside (IPTG), the recombinant protein was detected in bacteria. Finally, the bacteria were lysed by sonication, and the recombinant protein was purified by nickel affinity chromatography and DEAE anion exchange chromatography. The protein was confirmed to be oIFN-τ, which mainly existed in the soluble lysate fraction, as proven by SDS-PAGE and Western blot assays. Purified IFN-τ exists mostly in a soluble form, and its anti-vesicular stomatitis virus (VSV) activity reached 7.08×10(6)IU/mL.