Orthogonal pre-use and post-use efficiency testing for single-use anion exchange chromatography.

Three efficiency tests for single-use AEX chromatography devices have been developed and applied to six capsule formats of a new, salt tolerant, single-use AEX product. All the tests have been designed to be performed with simple equipment and common reagents. By performing each of the three tests on undamaged capsules and capsules intentionally damaged with small defects, in tandem with Phi-X174 challenges in a high-salt buffer, relationships between test results and viral clearance have been obtained. A pre-use pressure-based installation verification test is simply performed during equilibration of the device and effective at identifying gross bypass defects, for example, due to internal seal breakage. Passing outcomes of a post-use installation validation bubble point test are associated with ≥ 5 log reduction value (LRV) of viral clearance. A new, non-destructive, pre-use AEX capacity test involves challenging the device with chloride ions and is orthogonal to the other two tests in that it can detect chemical defects, as well as mechanical ones. Passing outcomes of this test correspond to > 2 LRV viral clearance and provide in situ assurance of the expected AEX dynamic capacity prior to use. Selection of a pair of pre-use and post-use tests can provide robust risk reduction with respect to viral clearance by single-use AEX devices in biopharmaceutical purifications.

Profiles of Long Noncoding RNAs in Human Naive and Memory T Cells.

We employed whole-genome RNA-sequencing to profile mRNAs and both annotated and novel long noncoding RNAs (lncRNAs) in human naive, central memory, and effector memory CD4+ T cells. Loci transcribing both lineage-specific annotated and novel lncRNA are adjacent to lineage-specific protein-coding genes in the genome. Lineage-specific novel lncRNA loci are transcribed from lineage-specific typical- and supertranscriptional enhancers and are not multiexonic, thus are more similar to enhancer RNAs. Novel enhancer-associated lncRNAs transcribed from the IFNG locus bind the transcription factor NF-κB and enhance binding of NF-κB to the IFNG genomic locus. Depletion of the annotated lncRNA, IFNG-AS1, or one IFNG enhancer-associated lncRNA abrogates IFNG expression by memory T cells, indicating these lncRNAs have biologic function.

Development of adsorptive hybrid filters to enable two-step purification of biologics.

Recent progress in mammalian cell culture process has resulted in significantly increased product titers, but also a substantial increase in process- and product-related impurities. Due to the diverse physicochemical properties of these impurities, there is constant need for new technologies that offer higher productivity and improved economics without sacrificing the process robustness required to meet final drug substance specifications. Here, we examined the use of new synthetic adsorptive hybrid filters (AHF) modified with the high binding capacity of quaternary amine (Emphaze™ AEX) and salt-tolerant biomimetic (Emphaze™ ST-AEX) ligands for clearance of process-related impurities like host cell protein (HCP), residual DNA, and virus. The potential to remove soluble aggregates was also examined. Our aim was to develop a mechanistic understanding of the interactions governing adsorptive removal of impurities during filtration by evaluating the effect of various filter types, feed streams, and process conditions on impurity removal. The ionic capacity of these filters was measured and correlated with their ability to remove impurities for multiple molecules. The ionic capacity of AHF significantly exceeded that of traditional adsorptive depth filters (ADF) by 40% for the Emphaze™ AEX and by 700% for the Emphaze™ ST-AEX, providing substantially higher reduction of soluble anionic impurities, including DNA, HCPs and model virus. Nevertheless, we determined that ADF with filter aid provided additional hydrophobic functionality that resulted in removal of higher molecular weight species than AHF. Implementing AHF demonstrated improved process-related impurity removal and viral clearance after Protein A chromatography and enabled a two-step purification process. The consequences of enhanced process performance are far reaching because it allows the downstream polishing train to be restructured and simplified, and chromatographic purity standards to be met with a reduced number of chromatographic steps.