Background and Aims: IFN beta-1a is a recombinant protein which reduces the symptoms of Multiple Sclerosisdisease. The purpose of this study was comparison the effects of gamma irradiation and acid pH methods on the biological attributes of recombinant protein IFN beta-1a in order to viral inactivation.
Materials and Methods: Methods: IFN beta was produced by recombinant-DNA in CHO Cell line which include human IFN beta gene and divided in two parts. The acidity of one part was adjusted about pH=4 by hydrochloric acid and incubated two hours, then was returned back to initial pH=7 by NaoH (1 M). The second part was irradiated by a Nordian model 220 gamma irradiator, with different doses: 10, 25 and 50 kGy. The prepared samples with both methods were analyzed by SDS-PAGE and HPLC.
Results: The HPLC indicated decreasing in purity and protein content of gamma irradiated samples, whereas these properties for the acidic pH treated sample was the same as the standard sample. Aggregation of gamma irradiated IFN beta-1a protein and increasing of the protein molecular weight were shown by SDS-PAGE, but it was without any change in molecular weight (22.5 KDa) at acidic pH sample. Also, decreasing of IFN beta antiviral activity through decreasing its concentration has been shown via antiviral assay.
Conclusions: Conclusion: The low pH method can be used for viral inactivation without any change in structure and biological activity of IFN beta-1a but the results indicated differences between the irradiated and standard samples, whereas the acidic pH treated sample was the same as the standard.