The immune system extends this response to its treatments of self-antigens, softening reactions against allergens, the body, and digestive microorganisms. As the worms developed ways of triggering a beneficial immune response, humans came to rely on parasitic interaction to help regulate their immune systems.
The adaptive immune response is the body's second line of defense. The cells of the adaptive immune system are extremely specific because during early developmental stages the B and T cells develop antigen receptors that are specific to only certain antigens. This is extremely important for B and T cell activation.