Types of Immunity

Innate immunity is nonspecific. It is a generalized defense against all foreign invaders to hinder the infiltration and spread of disease. However, it rarely ever prevents disease entirely. Skin, tears, saliva, and mucus are barriers that make up this first line of defense. The inflammation of tissues that take place not long after injury or infection is also a part of innate immunity.

Adaptive immunity is made up of defenses specifically tailored to fight against the foreign invader. This defense can be called upon whenever a known invader attacks again in the future. Adaptive immune responses are reactions to antigens, which are structures on the surface of the invader.

There are four distinguishing properties that adaptive immunity has:

• Responds only after invader is present
• Displays memory by responding to an invader better the second time it invades
• Only attacks substances and components it recognizes as foreign
• Tailors each response to act only on a specific type of invader