許多致病原 (pathogens) 發展出獨特的方式逃避宿主免疫系統的毒殺，trypanosome 係以何種方式進行？
antigenic drift of variant-specific glycoprotein (VSG)
antigenic shift of variant-specific glycoprotein (VSG)
programmed rearrangements of variant-specific glycoprotein (VSG)
deletion of variant-specific glycoprotein (VSG)
