Characterization of the co‐elution of host cell proteins with monoclonal antibodies during protein A purification

Protein A chromatography is commonly used as the initial step for purifying monoclonal antibody biotherapeutics expressed in mammalian tissue culture cells. The purpose of this step, as well as later chromatography steps, is, in part, to remove host cell proteins (HCPs) and other related impurities. Understanding the retention mechanism for the subset of HCPs retained during this step is of great interest to monoclonal antibody (mAb) process developers because it allows formation of a guided HCP clearance strategy. However, only limited information is available about the specific HCPs that co‐purify with mAbs at this step. In this study, a comprehensive comparison of HCP subpopulations that associated with 15 different mAbs during protein A chromatography was conducted by a 2D‐LC‐HDMS^E approach. We found that a majority of CHO HCPs binding to and eluting with the mAbs were common among the mAbs studied, with only a small percentage (～10% on average) of a mAb's total HCP content in the protein A (PrA) eluate specific for a particular antibody. The abundance of these HCPs in cell culture fluids and their ability to interact with mAbs were the two main factors determining their prevalence in protein A eluates. Potential binding segments for HCPs to associate with mAbs were also studied through their co‐purification with individual Fc and (Fab′)₂ antibody fragments. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:708–717, 2016     

Application of base-catalysed reaction to the synthesis of dinucleotides containing the four common deoxyribonucleosides and of oligodeoxythymidylates.

The phosphorylation of nucleosides by a nucleoside phosphorofluoridate in the presence of potassium tert-butoxide is a very effective reaction for internucleotide bond synthesis in the case of pyrimidine deoxynucleosides. However, for the purine deoxynucleosides, yields are reduced due to competing reactions. The method was applied to the stepwise synthesis of oligothymidylates. The yield of the trinucleotide was good whereas that of the tetranucleotide was reduced due to the insolubility of the intermediate trinucleotide in the presence of potassium tert-butoxide.     

Geriatric patients in an acute medical ward.

During a nine-month study 160 out of 482 bed-weeks in an acute medical ward were accounted for by 11 patients who no longer needed to be there. This was unsatisfactory both for the 11 patients concerned and for those patients requiring admission for whom the beds were blocked.     

Migratory and postmigratory mouse primordial germ cells behave differently in culture

In all vertebrate groups, the progenitors of the germ line, the primordial germ cells (PGCs) arise extragonadally and move to the developing gonad early in embryonic development. We have examined the behavior of isolated pregonadal and gonadal PGCs in vitro on feeder layers of an embryo-derived cell line. Histochemically and serologically identified pregonadal germ cells are found to be actively motile in vitro and, furthermore, show behavior characteristic of invasive cells. PGCs isolated from the developing gonad, however, show little locomotory activity and are not invasive on the same cellular substrate. These observations suggest that PGCs undergo a major change in phenotype at the time of their entry into the gonad anlagen.     

Regulation of triglyceride biosynthesis in adipose and intestinal tissue

The synthesis of phosphatidic acid and di- and triglycerides via the glycerol-3-phosphate pathway is markedly inhibited by 2-monooleyl ether in microsomal and whole cell preparations obtained from adipose and intestinal tissue. Monoglycerides are also inhibitors under conditions in which their hydrolysis is minimized. A correlation between inhibition by, and the hydrolysis of, monoglycerides has been demonstrated. 2-Monooleyl ether is the most effective inhibitor of the several mono- and di- ethers and esters studied. The specificity of the inhibition of glycerol-3-phosphate acylation by 2-monoethers or 2-monoesters has been demonstrated because microsomal NADH- and NADPH-cytochrome c reductase activities were not significantly inhibited. The reported control mechanism for triglyceride biosynthesis is discussed in relation to the regulation of fatty acid uptake and release in adipose tissue and the absorption and metabolism of triglycerides by the intestinal mucosa.     

PERIPHERAL ARTERIOSCLEROSIS—Arterial Grafting Procedures—Indications and Results—Part I: Arteriosclerotic Aneurysms

In 32 cases aneurysms of the aorta and peripheral arteries were resected and replaced by grafts. The results from the use of homografts in 18 cases were more satisfactory than with the use of Ivalon in 14 cases. The abdominal aorta was the most frequent location of aneurysms.The current mortality rate of 5.5 per cent for resection of unruptured abdominal aneurysms indicates that resection and grafting are an effective means of reducing the high mortality of untreated aneurysms. Five ruptured aneurysms were excised, with a mortality rate of 40 per cent. The uniformly fatal outcome of untreated ruptured abdominal aneurysms makes it obligatory for the surgeon to operate immediately after the diagnosis is first made.     

Some factors that affect the annual cycle of the winter moth, Operophtera brumata (L.) (Lepidoptera: Geometridae) in western Europe

Egg development rate in the winter moth (Operopbtera brumata (L.)) is increased by higher temperatures between at least 6.0° C and 18° C. Pupal development rate is, in general, reduced by higher temperatures. Therefore, lower temperatures in northern localities and at high altitudes in Europe increase the duration of the egg stage and decrease that of the pupa. Inherent differences in the eggs and pupae from different localities increase the effect of temperature differences.

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Resume La température affecte directement le taux de développement des oeufs et inversement celui des pupes chez la phalène hiémale, Operopbtera brumata (L.). Dans le nord de l'Europe, une température relativement basse a pour effet de prolonger la durée du stade de l'oeuf et de raccourcir proportionnellement celle du stade de la pupe, tandis que dans le sud de l'Europe avec de plus hautes températures, l'effet est contraire. Les différences inhérentes aux oeufs et aux pupes dans diverses localités augmentent l'effet des différences de température.