The Contamination Triangle: A New Model for Assessing the Risk of Biological Process Contamination and Performing Investigations
by Bill Ogden
Volume 15, Issue 1 (Spring 2016)
Microbial contamination is of great concern in pharmaceutical and biotech manufacturing. Many organizations struggle with determining the root cause of contamination when it occurs, and identifying effective safeguards to prevent future contaminations. This article will introduce a new model for understanding microbial contamination in biopharmaceutical and sterile products and processes. The “Contamination Triangle” identifies the three factors necessary for microbial ingress into a sterile (or pure) system. The use of this model will provide guidance for contamination investigations, clarify the explanation of the contributing root causes in Non-Conformances, and assist in identifying risks and risk mitigation measures as part of a Failure Modes and Effects Analysis (FMEA) or other risk assessment method...
Citation:
Ogden B. The contamination triangle: a new model for assessing the risk of biological process contamination and performing investigations. BioProcess J, 2016; 15(1): 49–53. https://dx.doi.org/https://dx.doi.org/10.12665/J151.Ogden.
Posted online April 7, 2016.
Antibody-Dependent Cellular Phagocytosis: The Mechanism of Action That Gets No Respect
A Discussion About Improving Bioassay Reproducibility
by Ulrike Herbrand, PhD
Volume 15, Issue 1 (Spring 2016)
Antibody-dependent cellular phagocytosis (ADCP), which relies on macrophages to attack and devour tumor cells following antibody binding, is a potentially useful mechanism of action (MOA) for antibody drug developers and vaccine makers to consider in determining product efficacy. Unfortunately, it is often ignored in favor of more accessible MOAs driving biological function such as antibody-dependent cellular cytotoxicity (ADCC) because the assays are tedious to prepare, perform, and reproduce. This article will summarize a number of those challenges and discuss how novel approaches, such as a reporter-gene assay that replaces the macrophages with an engineered cell line, are more reliable in measuring this neglected MOA. We will also discuss why this could help developers better understand how their biosimilars compare to the originator product...
Citation:
Herbrand U. Antibody-dependent cellular phagocytosis: the mechanism of action that gets no respect — A discussion about improving bioassay reproducibility. BioProcess J, 2016; 15(1): 26–9. https://doi.org/10.12665/J151.Herbrand
Posted online April 7, 2016.
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Development of a Novel Flow Cytometry-Based Titration Assay to Quantify Herpes Simplex Virus Type 1 (HSV-1)
by Brittany P. Lassiter, Adrianna V. Ferraioli, Kenji M. Cunnion, Patric S. Lundberg, and Neel K. Krishna
Volume 15, Issue 1 (Spring 2016)
Plaque assays have traditionally been a reliable way to determine the titer of a lytic virus. However, this method has several shortcomings in that it is time-consuming, labor intensive, and suffers from limited sensitivity. In this article, we describe a novel flow cytometry-based titration assay to quantify green fluorescent protein-labeled herpes simplex virus type 1 (HSV-1-GFP). Using this assay, we were able to directly quantify ten-fold dilutions of the virus in which every GFP-positive cell could be counted. In a head-to-head comparison with a traditional plaque assay, the flow cytometry assay showed a greater linear range and was accomplished in less than half the time of the plaque assay. Additionally, the cells prepared for flow cytometry could also be directly visualized by fluorescence microscopy. These results with HSV-1-GFP show proof of concept and are of practical use to herpesvirus researchers. Additionally, this technique could be easily modified to study other lytic or non-lytic viruses using antibodies against viral antigens...
Citation:
Lassiter BP, Ferraioli AV, Cunnion KM, Lundberg PS, Krishna NK. Development of a novel flow cytometry-based titration assay to quantify herpes simplex virus type 1 (HSV-1). BioProcess J, 2016; 15(1): 43–8. https://dx.doi.org/10.12665/J151.Krishna.
Posted online February 17, 2016.
Signaling Substances Used in Plant Defense: HPLC-MS/MS Analysis of Jasmonates
by Tim Iven, Kirstin Feussner, Cornelia Herrfurth, and Elmar Herbig
Volume 14, Issue 4 (Winter 2015/2016)
Plants must be capable of responding to climatic fluctuations, diurnal rhythms, available supplies of water and nutrients, and insect attacks and infestations. To ensure such responses, plants need a network of regulating substances called phytohormones. These substances enable plants to respond to both biotic and abiotic stresses by initiating a cascade of orchestrated actions, and to trigger development-specific processes. In this article, we will discuss a highly sensitive analytical method for quantitative determination of phytohormones. The main representatives of the plant hormones are jasmonic acid (JA), cytokines, auxins, abscisic acid, salicylic acid, gibberellins, and strigolactones...
Citation:
Iven T, Feussner K, Herrfurth C, Herbig E. Signaling substances used in plant defense: HPLC-MS/MS analysis of jasmonates. BioProcess J, 2016; 14(4): 56–61. http://dx.doi.org/10.12665/J144.Herbig.
Posted online January 12, 2016.
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