In vitro studies on the mechanism of kinin formation by trypanosomes.

1. An investigation into the mechanism of kinin release in trypanosomiasis has been made in vitro.2. Trypanosomes contain a low level of kininase but no kinin-forming enzyme nor substrate for salivary kallikrein.3. The kininase activity in the plasma of infected rats does not differ from that of normal animals, and trypanosomes do not affect the breakdown of synthetic bradykinin by enzymes in the blood.4. In trypanosomiasis the kininogenase precursor in plasma is activated. The hypothesis is put forward that the antigen-antibody complex may be involved in this.