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Demonstrating the Genetic Stability of the Tuberculosis Vaccine BCG

May 13, 2016

Dr. Naoya Ohara, Professor of Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Division of Social and Environmental Sciences Department of Oral Microbiology, Dr. Takayuki Wada, Assistant Professor of Nagasaki University Institute of Tropical Medicine Department of International Health, and their colleagues have performed the genome sequencing analysis of seven lots of BCG vaccine for tuberculosis. It was confirmed that each lot analysed in the study has few spontaneous mutations and is very stable. It is also suggested that the sequencing techniques used in the study are powerful and valid tool to detect mutations in live bacterial vaccine lots.

The result of this research was published online December 4, 2015 in Scientific Reports.
http://www.nature.com/articles/srep17827

BCG was established in the early 20th century by prolonged passaging of virulent clinical strain of Mycobacterium bovis. Japanese BCG vaccine, Tokyo-172 strain, was distributed within Japan in 1924 and is one of the currently used reference substrains for the vaccine. Recently, this substrain was reported to contain two spontaneously arising, heterogeneous subpopulations. The proportions of the subpopulations changed over time in both distributed seed lots and commercial lots. To maintain the homogeneity of live vaccines, such variations and subpopulational mutations in lots should be restrained and monitored. However, the level of variations and mutations in the BCG vaccines derived from Tokyo-172 strain was unknown.

The genome sequencing data showed that seven lots of BCG vaccine derived from Tokyo-172 strain have few mutations and are stable. That could confirm the safety of the vaccines.

Contact information

Mototaka Senda, Ph.D.
Director, Okayama University Silicon Valley Office
Organization for research Promotion and Collaboration, Okayama University
2450 Peralta Blvd. #222
Fremont, CA 94536

Naoya Ohara, D.D.S., Ph.D.
Department of Oral Microbiology, Division of Social and Environmental Sciences
Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University

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