High-throughput ion exchange purification of positively charged recombinant protein in the presence of negatively charged dextran sulfate

Tissue distribution of 35S-metabolically labeled neublastin (BG00010) in rats

Neublastin (NBN) is a neurotrophic growth factor that promotes the survival and regenerative properties of nociceptive neurons and has been tested in clinical trials as a treatment for neuropathic pain in individuals with sciatica and painful lumbosacral radiculopathy. Like many low molecular weight heparin binding proteins, NBN is rapidly cleared from the blood following systemic administration. To explore ADME properties of NBN in rats, we used metabolically ³⁵S-labeled NBN following IV and SC administration quantifying counts and intact protein in kidney, liver, brain, serum, and urine at 5 min, 8 h, 24 h and 48 h, and biodistribution in whole body carcasses by QWBA at 2, 8, 48, 96, and 168 h post dose. NBN is rapidly taken up by tissues mainly by liver and kidney and then degraded. Products of degradation are excreted in urine or recycled and utilized for resynthesis. The data we generated for NBN provides a first look at the complex clearance mechanisms for this protein and should aid in the design of ADME studies for other heparin binding proteins.

Q Sepharose micro-column chromatography: A simple screening method for identifying beta thalassemia traits and hemoglobin E carriers

OBJECTIVES

For beta thalassemia control program in pregnancy, mass screening of the carrier state by determination of the hemoglobin (Hb) A₂ and Hb E proportions and mutation analysis is a preferred method for making prenatal diagnoses. Q Sepharose micro-column chromatography, developed for the determination of Hb A₂ and Hb E for screening purposes, was compared with high performance liquid chromatography (HPLC) to ascertain its relative accuracy and reliability.

DESIGN AND METHODS

Results using Q Sepharose micro-column chromatography in 350 blood specimens, including 50 samples genetically proven to be beta thalassemia heterozygotes, were compared to HPLC for validation. An additional study was conducted to test a clinical application on a large-scale survey for beta thalassemia in 1581 pregnant women and their spouses.

RESULTS

The mean (±SD) Hb A₂ proportions in the normal and genetically proven beta thalassemia heterozygotes were 2.70±0.40% and 6.30±1.23%, respectively, as determined by Q-Sepharose micro-column chromatography, and 2.65±0.31% and 5.37±0.96%, respectively, as determined by HPLC. The mean Hb E proportions in the Hb E heterozygotes were 23.25±4.13% and 24.72±3.5% as determined by Q Sepharose micro-column chromatography and HPLC, respectively. In the large-scale survey for beta thalassemia, 23 at risk couples were detected. Seven affected fetuses were identified by prenatal diagnosis.

CONCLUSIONS

Q Sepharose micro-column chromatography was found to be reliable, reproducible and well-suited for large-scale surveys. Additionally, by being reusable and convenient, this simple and economical chromatography method may be an alternative means to screen for beta thalassemia and Hb E carriers in the mass population.

Arginine as an eluent overcomes the hindrance of monoclonal antibody quantification by dextran sulfate in protein A affinity chromatography

Analytical chromatography using protein A affinity columns was employed for the fast and simple quantitative analysis of monoclonal antibodies (mAb) from suspension cultures of recombinant Chinese hamster ovary (rCHO) cells. Reliable results could not be obtained from analysis of rCHO cell culture supernatants containing dextran sulfate using elution buffers such as phosphate, glycine, or MgCl2 . These problems increased as the number of analysis and the concentration of dextran sulfate in samples increased. Arginine was identified as an alternative eluent to overcome the hindrance by dextran sulfate. When the samples contain dextran sulfate up to 100 mg/L, the elution buffer containing 0.6-1.0 M arginine at pH 3.0-3.8 is useful for the effective analysis. Reproducible results in the mAb quantification could be obtained by this developed arginine elution buffer from rCHO cell culture supernatants containing dextran sulfate.