Correlation between the results of two analytical methods for measuring measles virus neutralizing antibodies in source plasma and therapeutic immunoglobulin products.

Patients with primary immunodeficiency disorders are vulnerable to infectious diseases. Intravenous immunoglobulin (IVIG) therapeutic products manufactured from human plasma are employed widely to protect patients from pathogens such as measles virus, which causes a potentially fatal and contagious disease. Therefore, health authorities stipulate a minimum titer of measles neutralizing antibodies (mnAbs) in IVIG products to ensure efficient protection. In general, mnAb titers are measured in a cell-based neutralization assay; however, this assay is labor intensive and time consuming, and the results are variable. Here, we compared a cell-based neutralizing assay with several ELISA tests to evaluate whether ELISAs can overcome the limitations of cell-based assays. The mnAb concentrations measured by the ELISAs showed a strong and significant positive correlation with those measured in a cell-based assay. Also, strong positive correlations were identified for measurement of individual source plasmas, which are used as raw materials for manufacturing IVIG products. Measurement by ELISA revealed that about 80% of 198 source plasmas had mnAb concentrations of <500 mIU/mL. These results suggest that quantitative ELISAs based on relevant antigens allow reliable and comprehensive measurement of mnAb concentrations in source plasmas and drug product; these ELISAs are also faster and more accurate than cell-based assay.

Characterisation of the site-specific monoPEGylated rhG-CSF analogue pegteograstim.

We describe the characterisation of a novel monoPEGylated recombinant human granulocyte colony-stimulating factor analogue, pegteograstim (Neulapeg), prepared by site-specific 20 kDa maleimide-PEG conjugation. An additional cysteine was inserted between Gly136 and Ala137 of filgrastim (methionyl human granulocyte colony-stimulating factor) for site-specific PEGylation, and Cys18 of filgrastim was replaced with Ser18 to prevent unwanted PEGylation. Pegteograstim was produced by Escherichia coli and purified by cation exchange chromatography, and its structural, physicochemical, biological and immunological properties were investigated. Male Sprague-Dawley rats were administered pegteograstim (100 µg/kg) and the pharmacokinetics and pharmacodynamics compared with those of filgrastim. The results of long-term stability testing of pegteograstim revealed no significant change in its quality attributes at 2-8 °C for 36 months. In addition, pegteograstim was stable under the accelerated conditions (25 ± 2 °C, RH of 60 ± 5%) for 6 months. The site-specific monoPEGylated pegteograstim is a highly pure, stable and novel drug for long-lasting treatment of chemotherapy-induced neutropenia.

Proteomic analysis of phosphotyrosyl proteins in morphine-dependent rat brains.

Morphine has been used as a potent analgesic, having a high propensity to induce tolerance and physical dependence following their repeated administration. Although the mechanisms that underlie the development of dependence on morphine remain unclear, previous studies suggested that phosphorylations of diverse types of cellular proteins are crucial determinants of the neuroadaptive mechanisms associated with morphine dependence. Thus, understanding global phosphorylation events induced by chronic morphine administration is essential for understanding the complex signaling mechanisms of morphine dependence. This study characterized the alteration of tyrosine phosphorylation of frontal cortical proteins in morphine-dependent rat brains using a proteomic approach. Dependence was produced by continuous intracerebroventricular (i.c.v.) infusion of morphine (26 nmol/microl/h) for 72 h via osmotic minipumps in rats. Phosphotyrosyl (p-Tyr) protein spots in brain frontal cortical regions were detected by two-dimensional electrophoresis (2-DE) and immunoblotting with anti-p-Tyr-specific antibodies. The protein spots showing significant changes in tyrosine phosphorylation were identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). Similar patterns of protein expression were detected by 2-DE gels in morphine-dependent and saline-treated control rat brains. However, phosphotyrosine 2-DE images of the frontal cortical proteins from saline-treated control and morphine-dependent rat brains were apparently different. The densities of most matched p-Tyr protein spots were increased in morphine-dependent rat brains compared with that of control samples. Additional p-Tyr protein spots were detected in 2-DE image of morphine-dependent rat brains. Fifty of p-Tyr protein spots, corresponding to 40 different proteins, were identified from 2-DE gels of morphine-dependent rat brains. The identified proteins include enzymes, cytoskeletal proteins, cell signaling molecules, and other proteins. In conclusion, the first available phosphotyrosine proteomic resources of morphine dependence were established using an animal model. The findings illustrate the potential of proteomics as an effective technique for studying phosphorylation events of morphine dependence in brains.

Proteomic analysis of phosphotyrosyl proteins in the rat brain: effect of butorphanol dependence.

Butorphanol (17-cyclobutylmethyl-3,14-dihydroxymorphinan) tartrate (Stadol) is a mixed agonist-antagonist opioid analgesic agent that is about five to seven times as potent as morphine in analgesic effects. The chronic use of butorphanol produces physical dependence in humans and animals. Phosphorylation plays a very important role in developing butorphanol dependence; however, global phosphorylation events induced by chronic butorphanol administration have not been reported. The aim of this study is to determine the alteration of tyrosine phosphorylation of brain frontal cortical proteins in butorphanol-dependent rats using a proteomic approach. Dependence was produced by continuous intracerebroventricular (i.c.v.) infusion of butorphanol (26 nmol/microl/hr) for 72 hr via osmotic minipump in rats. Similar patterns of protein expression were detected by two-dimensional electrophoresis (2-DE) in brain frontal cortex of butorphanol-dependent and saline-treated control rats. All 65 phosphotyrosyl (p-Tyr) protein spots detected in pH 3-10 phosphotyrosine 2-DE of control rat brains were detected in butorphanol-dependent rat brains. The densities of most p-Tyr protein spots were increased in butorphanol-dependent rat brains compared to saline-treated control samples. Eighteen additional p-Tyr protein spots were detected in pH 3-10 2-DE images of butorphanol-dependent rat brains. Immobilized pH strips with three different narrow pH ranges were examined to improve the resolution of p-Tyr proteins in 2-DE gels. Fifty-three p-Tyr protein spots were identified as known proteins involved in cell cytoskeleton, cell metabolism, and cell signaling. This proteomic approach can provide useful information for understanding the complex mechanism of butorphanol dependence in vivo.