Development of Immunity to Reinfection During Chemoprophylaxis of Trypanosomiasis with a New Antimony Derivative

It is confirmed that a single intraperitoneal or subcutaneous injection of a sodium salt derived from melaminyl-phenylstibonic acid (Compound 122) confers a long-lasting protection against numerous consecutive infections of the mouse with Trypanosoma equiperdum. This protection is also obtained by oral administration of the compound. In infected mice which have been cured with this product, an immunity to reinfection with Trypanosoma equiperdum is achieved. The passive transfer of this immunity has been demonstrated. A similar state is reached if the product is injected first, and subsequently, reinfections with small amounts of trynanosomes are made. It is not established whether this acquired immunity to reinfection plays a role in the prophylaxis conferred by Compound 122.