Replacement of primary monkey kidney cells by L20B cell line in the test for effective inactivation of inactivated poliovirus vaccine.

Absence of 'live' residual poliovirus in Inactivated Poliovirus Vaccine (IPV) is routinely checked using Primary Monkey Kidney Cells (PMKC). However, the increasing demand for IPV and the ethical, technical and safety issues associated with the use of non-human primates in research and quality control, has made the replacement of primary cells with an established cell line a priority, in line with the principles of the 3Rs (Replacement, Reduction and Refinement in animal testing). As an alternative to PMKC, we evaluated the L20B cell line; a mouse cell-line genetically engineered to express human poliovirus receptor, CD155. L20B is already used for the detection and diagnosis of poliovirus in clinical samples. We demonstrate the stability of L20B cells in terms of CD155 gene and receptor expression, and permissivity to polioviruses for at least 16 sequential passages. In addition, the L20B cell line was found to be at least as sensitive as PMKC in detecting the presence of 'live' poliovirus in IPV samples. Equivalence or superiority of L20B cells versus PMKCs was demonstrated for assessing the presence of residual 'live' poliovirus in formaldehyde-inactivated preparations for the three poliovirus serotypes. These results demonstrate that the L20B cell line is a suitable alternative to PMKC in IPV inactivation testing.

Validation of a PCR coupled to a microarray method for detection of mycoplasma in vaccines.

The revised section of the European, United States, and Japan Pharmacopeias on mycoplasma testing provided guidance for the set up and validation of a nucleic acid amplification technique (NAT) as an alternative method to agar culture and indicator cell culture compendial methods. The CytoInspect™ method, based on Polymerase Chain Reaction (PCR) coupled to microarray analysis, has been selected for detection and identification of mycoplasma in vaccines. To replace compendial methods, the alternative method must demonstrate equivalence in both limit of detection (LOD) and specificity compared with compendial methods. Here, we summarize the validation of the CytoInspect™ method according to current pharmacopeia requirements. Validation of the robustness, sensitivity (at least 10 colony forming units/ml) and specificity of the CytoInspect™ method are demonstrated. Likewise, a comparability study was performed to compare the LOD for CytoInspect™ compared with the previously validated LOD for compendial culture tests.