Immunity is resistance to disease resulting from the presence of foreign substances or in the body. When this resistance is provided by antibodies released to body fluids, the immunity is called immunity. When living cells provide the protection, the immunity is referred to as immunity. The major actors in the immune response are two types of lymphocytes, the , which are aided by phagocytic macrophages. Because pathogens are likely to use as a means of getting around the body, and other lymphatic tissues / organs (which house the immune cells) are in an excellent position to detect their presence.