Vaccine inhibits thrombus formation in mice

This result suggested that S100A9 could prevent thrombus formation in mice that had already had a stroke.

Hemostatic parameters and safety

Additional experiments indicated that the S100A9 vaccine had no effect on hemostatic parameters as indicated by tail bleeding time, platelet count, activated partial thromboplastin time, and prothrombin time.

The researchers also evaluated the vaccine’s safety by examining immunologic responses.

Histological analysis at day 147 after the first immunization revealed no pathological changes, such as CD4+ T-cell infiltration or activation of F4/80+ microglia/macrophages.

The immunized mice had predominantly IgG1 responses. This indicated that the S100A9 vaccine selectively induced primary T helper 2 responses.

“We are continuing our research in hopes of being able to start clinical trials between 5 and 10 years from now, but there are differences between mice and humans in how the vaccine will be recognized by the immune system,” Dr. Nakagami explained.

“We should be able to overcome such problems and believe this vaccine provides a very promising strategy in secondary prevention of stroke.”

This research was funded by the Mochida Memorial Foundation for Medical and Pharmaceutical Research, the Japan Cardiovascular Research Foundation, the SENSHIN Medical Research Foundation, and the Japan Agency for Medical Research and Development.

Dr. Nakagami and five of the eleven authors have applied for a patent for the S100A9 vaccine.

Dr. Nakagami and five other authors are affiliated with departments at Osaka University that receive financial support from AnGes, DAICEL, FunPep, Novartis, Shionogi, Boehringer, and Rohto. One author is a founder, stockholder, and former board member of AnGes.