PlasmaCap EBA: An innovative method of isolating plasma proteins from human plasma.

BACKGROUND AND OBJECTIVES: The growing demand for immunoglobulin (IG) requires development of improved plasma fractionation methods to provide higher yields in a cost effective, scalable manner without compromising product purity and efficacy. A novel protein extraction method, utilizing expanded bed adsorption (EBA) chromatography, has been developed. PlasmaCap IG (10% liquid formulation intravenous IG [IVIG]) is the first plasma-derived product manufactured using PlasmaCap EBA technology. MATERIALS AND METHODS: The PlasmaCap EBA platform consists of a series of consecutive columns which bind a target protein, or group of proteins, in their native state directly from cryo-poor plasma. EBA chromatography includes five key steps: (1) expand, (2) sanitize and equilibrate, (3) load, (4) wash and (5) elute. These steps are made possible using high-density tungsten-carbide agarose beads, suspended by upward flow. The PlasmaCap EBA process was evaluated during Evolve's clinical campaign for scalability, product quality and yield. RESULTS: PlasmaCap EBA technology can be predictably scaled by maintaining the minimum residence time and residence time distribution for EBA columns of different diameters. Scalability of the manufacturing process was demonstrated by the 50-fold volumetric increase from laboratory-scale lots to clinical-scale lots. The process is also associated with enhanced product purity, such as lower aggregates. The PlasmaCap EBA process is expected to have the same or better yield and purity at commercial scale production compared to the clinical campaign. CONCLUSION: The PlasmaCap EBA platform was used to successfully develop PlasmaCap IG (10% liquid formulation IVIG) with proven scalability, product quality and yield.

Cleavage and cytoplasmic relocalization of histone deacetylase 3 are important for apoptosis progression.

The apoptotic process is accompanied by major changes in chromatin structure and gene expression. The apoptotic genetic program is progressively set up with the inhibition of antiapoptotic genes and the activation of proapoptotic ones. Here, we show that the histone deacetylase 3 (HDAC-3), which is a known co-repressor of many proapoptotic genes, is subjected to proteolytic cleavage during apoptosis in a cell type- and species-independent manner. This cleavage is caspase dependent and leads to the loss of the C-terminal part of HDAC-3. The cleaved form of HDAC-3 accumulates in the cytoplasm. Furthermore, we found that forced nuclear localization of HDAC-3 decreases the efficiency of apoptosis induction, indicating that HDAC-3 cytoplasmic relocalization is important for the apoptotic process. Finally, we observed that HDAC-3 cleavage allowed increased histone acetylation and transcriptional activation on a proapoptotic HDAC-3-target gene, the Fas-encoding gene. Altogether, our results thus indicate that HDAC-3 cleavage is crucial for efficient apoptosis induction because it allows the activation of some proapoptotic genes during apoptosis progression.

Functional and physical interaction between the histone methyl transferase Suv39H1 and histone deacetylases.

The histone methyl transferase Suv39H1 is involved in silencing by pericentric heterochromatin. It specifically methylates K9 of histone H3, thereby creating a high affinity binding site for HP1 proteins. We and others have shown recently that it is also involved in transcriptional repression by the retinoblastoma protein Rb. Strikingly, both HP1 localisation and repression by Rb also require, at least in part, histone deacetylases. We found here that repression of a heterologous promoter by Suv39H1 is dependent on histone deacetylase activity. However, the enzymatic activity of Suv39H1 is not required, since the N-terminal part is by itself a transcriptional repression domain. Coimmunoprecipitation experiments indicated that Suv39H1 can physically interact with HDAC1, -2 and -3, therefore suggesting that transcriptional repression by Suv39H1 could be the consequence of histone deacetylases recruitment. Consistent with this interpretation, the N-terminal transcriptional repression domain of Suv39H1 bound the so-called 'core histone deacetylase complex', composed of HDAC1, HDAC2 and the Rb-associated proteins RbAp48 and RbAp46. Taken together, our results suggest that a complex containing both the Suv39H1 histone methyl transferase and histone deacetylases could be involved in heterochromatin silencing or transcriptional repression by Rb.