What type of white blood cells are not found in blood?
Immunity and the Immune Response The immune system has an intricate network of checks and balances that can be categorized as innate and learned immunity. Everyone is born with innate immunity. The components of the immune system involved in innate immunity – macrophages, neutrophils, and complement – react similarly to all foreign substances, and the recognition of antigens does not vary from person to person. As its name indicates, learned immunity is acquired. At birth, a person’s immune system has not yet encountered the outside world or started to develop its memory files. The immune system learns to respond to every new antigen encountered. Learned immunity is, therefore, specific to the antigens encountered during a person’s lifetime. The hallmark of specific immunity is its ability to learn, to adapt, and to remember. The immune system carries a record or memory of every antigen a person encounters, whether through the lungs (by breathing), the intestine (by eating), or the ski
