Immune activity has a benefit and a cost. The negative side of immunity is the production of distressing symptoms, acute and chronic diseases. The term hypersensitivity describes increased, damaging immune response.This system comprises of many cells that work together to protect the body from foreign invaders such as bacteria, viruses, parasites as well as tumours. The immune system is divided into two primitive forms, the innate and adaptive systems. The roles for both types are vital in the immune system; the innate is the rapid, non-specific primary response against any foreign material the body encounters, whereas the adaptive system is a secondary response and a more specific line of defence. The adaptive as well as the innate responses initiation are hugely associated with each other. The innate response consists of many components; these include mechanical, chemical, humoral as well as cellular barriers. The main line of defence in the innate system is the cellular component; there are different types of cells involved, however, the most critical cell of all other different immune cells is called a macrophage. Macrophages are a phagocytic cells originated from monocytes, a form of blood leukocytes. Monocytes are made by bone marrow in the myeloid lineage through committed haematopoietic stem cells in a process called haematopoiesis. Macrophages carry out indispensable roles in the immune system; they are involved in both of innate and adaptive responses. Thus, macrophages are always referred as the cells that ‘bridge’ the innate and adaptive systems.
Immune cells circulating in the blood are collectively referred to as white blood cells. White one the most common medical lab tests. WBC groups include lymphocytes, neutrophils, eosinophils, basophils, and monocytes. These cells are made in the bone marrow and the lymphatic tissues (lymph nodes, thymus, spleen, and gut-associated lymphatic tissue). Some cells identify the characteristic molecular shape of an antigen and respond by proliferation. A virus, for example, will have protein identifiers stuck to its capsule which mark it, much like an ID badge. Several cell populations will emerge when the virus is present to identify and combat it. One cell group manufactures antibody, a protein specific to one antigen. Molecules in the food supply, especially proteins, act as antigens. Food additives and contaminants may increase the probability of allergic reactions to food. Immune cells do not know the difference between viral, bacterial or food antigens. We expect and regularly observe similar immune