Expression of recombinant human serum albumin in the methylotrophic yeast; Hansenula polymorpha

Human serum albumin [HAS] is the major protein component of human plasma. It plays a very important role in transporting of macro molecules and maintaining the normal osmolarity. It is used as a therapeutical protein in patients with hypoalbuminemia and acute bleeding and burning. Albumin consumption in the world is about 500 ton/year. The aim of this research is to study the production of rHSA in shake flask culture by Hansenula polymorpha. H. polymorpha was used for the production of recombinant human serum albumin [rHSA] in several of shake flask culturing; expression of rHSA was investigated relating several parameters affecting the expression of HSA. To optimize the secretory expression of rHSA under the control of FMD promoter in H polymorpha RB-11 incubation time, culture media temperature and protease inhibitors were analyzed. This study not only established production of rHSA in yeast but also analyzed the correlation between affecting parameters and the level of HSA expression. Comparison of the HSA levels in the culture supernatants showed that the highest HSA yield was 17.6mg/l. The research shows that among three different temperatures [25°C,30°C and 37°C] 37°C was the best temperature and amongst three different incubation times [24h,48h and 72h] 48h was the optimum time and YNB 1% glycerol with buffer was the best derepression medium in comparison with others. Using these optimized conditions, stable production of rHSA of around 17.6mg/l was achieved. Our results suggest that affecting experssion factors improved in this study are suitable for production of recombinant albumin

Measurement of serum level of IgA-alpha[1]-AT complex in patients with rheumatoid arthritis

Rheumatoid arthritis [RA] is a severe chronic inflammatory disease that can not be easily rapidly treated. It can cause joint destruction and disability. Generally some laboratory tests, such as Rheumatoid Factor [RF], Erythrocyte Sedimentation Rate [ESR] or C-Reactive Protein [CRP] can be used for diagnosis and monitoring of the rheumatoid arthritis. However, they are not always ideal. In inflammatory diseases such as rheumatoid arthritis, the level of IgA will increase in serum; the surplus IgA can then react with some of the serum proteins such as Alpha-1-antirypsin [alpha[1] AT] to form a non-immune complex. The complex IgA - alpha[1]AT is formed by disulfide bonding between an active thiol group available on the both proteins. Some reports suggested that this complex is a good marker for RA disease without false results, while RF test has some false negative results. In this study the level of IgA-alpha[1]AT complex in thirty seven RA patients and in forty four normal subjects by ELISA methods using anti- alpha[1] antirypsin monoclonal and anti-IgA polyclonal HRP conjugated antibodies was evaluated. Routine laboratory tests of RF, CRP and ESR in patients and controls were also investigated. Our results showed that IgA-alpha [1] AT complex level in patients [43.7 +/- 15.4] is significantly higher than controls [21.5 +/- 8.3] [p<0.05]. There were significant differences between the sera complex levels in patients and controls. The RF results revealed eleven false negatives [30%] while the level of complex had only one false result [3%]. Instead of RF, a rapid and sensitive ELISA test for IgA-alpha[1]AT complex level in RA patients is strongly recommended