What is Natural Immunity
Natural immunity describes the state of being able to resist illnesses; such a condition originates in a healthy immune system. This form of immunity is resistance that one inherits from one’s parents, in contrast to acquired immunity, which one develops over the course of one’s life. Acquired immunity is built up when one suffers from and beats a given illness; memory cells in the immune system essentially learn the illness and remember how to beat it in the future.
Natural immunity confers that ability on an infant to some degree, allowing his immune system to identify and fight threats. Natural immunity ensures this is not a problem in healthy infants; their immune systems are already capable of distinguishing self from non-self, of identifying threats, and of fighting a number of common ailments.
The workings of natural and of acquired immunity are closely related to molecules called antigens. Antigens are substances that provoke some form of immune response. Once the immune system confronts a given antigen, it tends to remember it and is able to mount a much more effective defense the next time the antigen that provoked the response appears. Specific immune responses are targeted at specific threats, while nonspecific immune responses are effective against a wide variety of issues.
Most of the capabilities of natural immunity are focused around nonspecific immune responses that can handle many types of threats. After birth, as an individual is exposed to a variety of illnesses and antigens through sickness or through vaccines, he begins to build up a library of specific, targeted immune responses that allow him to effectively deal with a variety of specific threats.