ABSTRACT
Most pathogens that threaten the human body are prevented from establishing infection, and those infections that do occur are usually terminated by the actions of innate and adaptive immunity. In this situation there is strong pressure on pathogens to evolve ways of escaping or subverting the immune response. Microorganisms with such advantages compete successfully against other potential pathogens to exploit the resources of the human body. The first part of this chapter describes examples of the different types of mechanism they use.
