BACKGROUND: The veterinary Rabies vaccine was produced using BHK-21 cells and PV strain. Although various protocols have been suggested for virus purification, they have an adverse effect on the final production and require further optimization.OBJECTIVES: The present study aimed to optimize the concentration and purification of the virus for rabies vaccine production.METHODS: First of all, the Pasteur virus strain (PV) was cultured by using BHK 21 cells with DMEM media contain bovine fetal serum (7 %) for five days. Subsequently, the virus purification was done via tangential flow filtration (TFF) system. The quality of purifying viruses was an assessment with titration and SDS-PAGE. Secondly, the virus inactivation was optimized using Minitab software based on three factors, namely time, temperature, and concentration. Afterwards, the inactivity of the samples was tested on mice. Finally, the virus potency was evaluated by the National Institute of Health (NIH) method.RESULTS: The viral titration test in TFF samples revealed that viral titer increased in comparison with the control group (P<0.05). The SDS-PAGE analysis of the purified and concentrated samples showed that the purified virus via TFF had a higher purity compared to the not-concentrated samples. Moreover, the NIH test indicated a 10-fold increase in potency result in the TFF group.CONCLUSIONS: The present study implied that the TFF method is highly suitable for condensation and purification of a high volume of viral fluid and could be applied on an industrial scale to increase the potency of the vaccine produced.

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.

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.