The Cross-talk between Innate and Adaptive Immunity
Induction of an immune response is only appropriate if the antigen recognized is derived from, or belongs to, a pathogen.
Activation of lymphocytes specific for self antigens, or innocuous persistent environmental antigens, is deleterious.
The adaptive immune response requires signals that provide information about the origin of the antigen and the type of response to be induced.
These signals are provided by the innate immune system.