Question

why the local defence system does not depend on previous exposures to infections????✔❤

Answer 1

The previous exposure of a human body part to infections gives rise to the production of antibodies in that part of the body.

These antibodies can prevent further virus infections through a number of biological procedures, thus protecting the body from many diseases.

However, the local body defenses, like the tears of the eyes, mucus of the nostrils, saliva of the mouth and gastric juice of stomach contain some enzymes that can kill many bacteria.

Moreover, the protective lining of the respiratory and digestive passages prevent the entry of infective germs into the body.