Pilot production of recombinant human clotting factor IX from transgenic sow milk

DNA aptamer affinity ligands for highly selective purification of human plasma-related proteins from multiple sources

Nucleic acid aptamers are promising ligands for analytical and preparative-scale affinity chromatography applications. However, a full industrial exploitation requires that aptamer-grafted chromatography media provide a number of high technical standards that remained largely untested. Ideally, they should exhibit relatively high binding capacity associated to a very high degree of specificity. In addition, they must be highly resistant to harsh cleaning/sanitization conditions, as well as to prolonged and repeated exposure to biological environment. Here, we present practical examples of aptamer affinity chromatography for the purification of three human therapeutic proteins from various sources: Factor VII, Factor H and Factor IX. In a single chromatographic step, three DNA aptamer ligands enabled the efficient purification of their target protein, with an unprecedented degree of selectivity (from 0.5% to 98% of purity in one step). Furthermore, these aptamers demonstrated a high stability under harsh sanitization conditions (100h soaking in 1M NaOH). These results pave the way toward a wider adoption of aptamer-based affinity ligands in the industrial-scale purification of not only plasma-derived proteins but also of any other protein in general.

A galactopoiesis accordant yield of functional recombinant human factor IX from homozygous transgenic pigs requires a large amount of vitamin K supplementation

Transgenic pigs failed to accord milk yield curve to lactate rhFIX-a vitamin K (VK) dependent protein even fed with VK enriched to 8 times higher than nutritional requirement. A further higher VK supplementation may be required. Homozygous transgenic sows (n = 4, 200 kg) at their 3rd nursing were divided into control and treatment groups and respectively received VK enriched and further menadione (soluble VK) supplemented diet (220 mg/kg VK enriched diet) for 33 days. At next lactation, control sows than received treatment and previous treated were fed on control diet. Results revealed that menadione treatment increased milk bioactivity of rhFIX from the 7th day of 73 to the 21st day of 153 IU/mL; it gradually decreased to 96 IU/mL on 35th day of lactation. Under control feeding, bioactivity remained relatively unchanged. However, milk rhFIX concentration and ratio of activated rhFIX responded little to the treatment. The menadione-induced bioactivity curve agrees with the known lactation pattern of sow means rhFIX secretion is still galactopoietic but requires high VK intake to show. The ineffectual VK spend on lactational carboxylation might be common in other mammary VK dependent expression system but can be effectively overcome by a high supplementation of menadione with a 5-folds improvement in quality.

Quantitative detection of residual porcine host cell DNA by real-time PCR

All biological products are derived from complex living systems and are often mixed with large numbers of impurities. For reasons of safety, residual host-cell DNA must be eliminated during processing. To assay host-cell DNA content in biopharmaceutical products derived from porcine sources, this study applies the quantitative real-time polymerase chain reaction (Q-PCR) method. The optimized assay in this study is based on the pol region of the porcine endogenous retrovirus (PERV). Assay validation results demonstrate that the proposed assay has appropriate accuracy, preciseness, reproducibility, and sensitivity. Primer and probe specificity are evaluated in real-time Q-PCR reactions using genomic DNA from rabbit, mouse, cat, hamster, monkey, human cell, yeast, and Escherichia coli as templates. The sensitivity of real-time Q-PCR is determined using genomic DNA from the porcine kidney cell line. The reliable detection range is within 0.5-10(5) pg/reaction. The limit of quantitation is 500 fg. The sensitivity of the assay meets the authority criterion. Moreover, the assay is applied to determine the level of host-cell DNA in recombinant human coagulation factor IX (rhFIX) from transgenic pigs. The real-time Q-PCR assay is thus a promising new tool for quantitative detection and clearance validation of residual porcine DNA when manufacturing recombinant therapeutics.

Purification of antibodies and antibody fragments using CaptureSelect™ affinity resins

Ever since the introduction of bacterial derived surface proteins like protein A that demonstrate a natural binding reactivity towards antibodies, affinity chromatography has evolved into a well-established technology for the purification of antibodies and antibody fragments. Although high selectivity is provided by these types of affinity ligands, not all antibodies or antibody fragments are covered, which then forces the use of non-affinity-based processes that are less selective and often result in lower one-step purity and yield. To fill these gaps, we here describe a novel range of CaptureSelect(™) affinity resins that enables immunoaffinity chromatography for a much broader range of antibody targets.