Press Release

Nagoya, Japan, January 12, 2010 - Medical & Biological Laboratories, Co., Ltd. (MBL), with the collaboration of Osaka University, has successfully generated several fully human monoclonal antibodies against pandemic A (H1N1 and H3N2) type influenza virus by utilizing blood samples from volunteers who were inoculated with influenza vaccine.

Professor Kazuyoshi Ikuta, Ph. D., at the Department of Virology, Research Institute for Microbial Diseases, Osaka University, has confirmed through in vitro experiments that the fully generated human antibodies can neutralize H3N2 influenza virus strains. Professor Ikuta is now evaluating the preventative and therapeutic effects in an infected mouse model. After completing in vivo experiments in infected animal models with the neutralizing antibodies, MBL plans to commence a collaborative clinical development program with a pharmaceutical company. These neutralizing human IgG antibodies against the influenza virus are expected to be effective in severe infections. In combination with anti-viral drugs these antibodies will have greater success than anti-viral drugs alone.

The therapeutic antibodies were generated by using a special cell line, called SPYMEG. This novel cell line is a human lymphocyte fusion partner, it was co-developed by associate professor Naomasa Yamamoto of Ohu University and MBL. SPYMEG is the cell line established by the cell fusion of MEG-01 with a murine myeloma cell line. Hybridoma cells of human origin are known to be prone to chromosome deletions. The SPYMEG cell line overcomes that problem, resulting in a higher reliability of cell fusion. Utilization of SPYMEG is a simpler and easier way to generate therapeutic monoclonal antibodies than chimerization, or humanization of mouse monoclonal antibodies generated from immunized mice

At present, MBL is conducting collaborative research to generate neutralizing monoclonal antibodies against swine-origin influenza A (H1N1). MBL is preparing to collaborate with more institutions regarding other infectious viruses.

The fully human monoclonal antibodies against pandemic A (H1N1 and H3N2) type influenza viruses were generated by the utilization of SPYMEG. The antibodies, originated from the blood of a convalescent volunteer recovering from influenza infection or vaccination, are expected to be effective and very safe.
Additionally, the simple principle and wide range of applications of this method may lead to the generation of therapeutic and prophylactic drugs to various infections such as avian influenza A (H5N1).

[Reference]

Biochemical and Biophysical Research Communications 387 (2009) 180–185

[Glossary]

Fully human antibody :
Recent therapeutic monoclonal antibodies, either of a chimeric, humanized or fully human antibody have been developed. The human amino acid sequence content of chimeric and humanized antibodies is approximately 66% and 90%, respectively. However, the fully human monoclonal antibody is constructed with 100% of human gene sequence, and is considered to be a much safer and less antigenic agent.

Neutralizing activity :
This means the activity that the antibody binds to membrane protein on the influenza virus surface and inhibits entering of the virus particle into human host cell. Anti-influenza agents suppress the growth of the virus through inhibiting the release of newly formed viral particles from infected cells.

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