An international collaborative study using two independent viability assays and an identity assay was carried out to evaluate the content and suitability of this candidate as WHO RR of BCG vaccine of Moreau RJ sub-strain.

BCG vaccine is a live attenuated strain of Mycobacterium bovis. Viability of the bacilli is critical for the stimulation of cellular immune responses that provide protection against M. tuberculosis; thus the effectiveness of the BCG vaccine. The cultural viable count assay is not strictly a measure of potency but it is commonly used as a surrogate marker for potency of BCG vaccines. In recent years, a modified ATP assay has been evaluated http://www.selleckchem.com/products/Adriamycin.html and adopted as an appropriate alternative method for estimating viability of BCG vaccines [4], [5], [6] and [7]. The multiplex PCR (mPCR) assay, a molecular

biology technique, has been introduced as a quality control test for identity of BCG vaccine [8]. This is a useful method to distinguish between different sub-strains of BCG that are currently being used in vaccine production. Specific regions of BCG, RD1, 2, 8, 14 and 16 have been successfully employed to produce a fingerprint that Ceritinib differentiates between sub-strains. The SenX3-RegX3 mycobacterial two-component system (responsible for the virulence and phosphate dependant gene expression of M. tuberculosis) has also been identified as a target site for use in identifying BCG sub-strains [8]. This assay has been successfully evaluated in a collaborative study as a molecular identity test for different sub-strains of BCG vaccine

[9]. As in a previous collaborative study [10], three independent methods were used to evaluate the suitability of BCG Moreau-RJ sub-strain as and a WHO Reference Reagent. Its content was defined as number of Colony Forming Units (CFU) and amount of ATP (ng) per ampoule. Multiplex PCR was used to identify the BCG sub-strain. The study report was approved by the WHO Expert Committee on Biological Standardization (ECBS) in October 2012 and this WHO Reference Reagent of BCG vaccine of Moreau RJ sub-strain has been made available for distribution since 2013. As these BCG Reference Reagents are live preparations, their stability in terms of viability has been monitored in NIBSC annually to ensure these preparations maintain their viability within an acceptable range at time of distribution. The BCG vaccine preparation of Moreau-RJ sub-strain was obtained lyophilized and sterile-filled in ampoules at commercial manufacturing facility with Good Manufacturing Practices (GMP). Five thousand ampoules were generously donated by a well-established BCG vaccine manufacturer (Fundacao Ataulpho de Pavia, Brazil) to WHO. This preparation (NIBSC code: 10/272) was shipped in dry ice and is stored at −20 °C at NIBSC.