Dr. Ira Shah, consultant pediatrician, Nanavati Hospital and BJ Wadia Hospital for Children, Mumbai
Editor - Pediatric OnCall What is our immune system is made up of? Our immune system is very important to maintain immunity in the body and prevent infections. It consists of various body cells and proteins. Infact the first barrier to infection of the skin and mucous membranes that line the nose, lungs and intestines. Our surrounding environment contains many bacteria and viruses. Skin and mucous membranes act as physical barriers and prevent entry of microbes in our body and internal organs. If the germ gets another entry in the body (when the skin is damaged or inflamed mucous membranes) of different cells (
) and proteins (antibodies) to help fight infection. What are white blood cells that help fight infection? Our blood is composed of 3 types of cells - (they carry oxygen to different parts of the body), white blood cells (they are composed of neutrophils, lymphocytes, monocytes, basophils and eosinophils, which help fight infection) and
(cell to prevent heavy bleeding when there is an injury). Other white blood cells have a different role in maintaining immunity. Neutrophils and monocytes (also called phagocytes) mainly absorb and kill germs. Neutrophils may migrate to foci of infection from the blood within minutes. They are responsible for the formation of "pus". Neutrophils significantly increase the infection and thus lead to increased number of leukocytes. Monocytes are in the flow, but also align the walls of blood vessels in organs such as liver, spleen and lungs. Monocytes in these organs are called macrophages. They capture the bacteria as they pass by in the blood and are especially useful for destroying fungus and tuberculosis bacilli. Lymphocytes mainly consist of B-lymphocytes, T lymphocytes and natural killer cells (NK cells). B-lymphocytes produce antibodies called immunoglobulins (they are highly specialized proteins that bind to shoot and make it easier or inactive phagocytes kill bacteria) B-lymphocytes may produce antibodies against virtually all living organisms.
T lymphocytes do not produce antibodies, and directly kill viruses, fungi and some bacteria. Some T cells called helper T-cell help B-lymphocytes to produce antibodies and help killer T cells to kill germs. Natural killer cells kill cells infected by viruses particularly herpes virus, Epstein-Barr virus and
. How different white blood cells form in the body? B cells develop from stem cells in bone marrow. T lymphocytes also develop from stem cells in bone marrow. In the early life of the fetus, immature T cells migrate to the thymus and develop into mature T lymphocytes. Mature T lymphocytes leave the thymus and then are in the spleen, lymph nodes, bone marrow and blood. If the fetus has no thymus, the mature T lymphocytes can not develop. NK cells and phagocytes also develop from stem cells in bone marrow. What are the different antibodies formed in B-lymphocytes? A. Immunoglobulin G (IgG)
2. Immunoglobulin A (IgA)
3. Immunoglobulin M (IgM)
4. Immunoglobulin E (IgE)
Another type of antibody formed IgD. Each antibody has a specific structure and specific actions. IgA antibodies present in the mucosa and helps prevent infection in the respiratory tract and intestines. IgM antibodies are the first antibodies formed in response to infection with the subsequent formation of lasix dosing IgG. IgE antibodies responsible for allergic reactions. What other components of the immune system? Another component of the immune system is the complement system. Complement system consists of 30 proteins produced by the liver in an inactive form. In contact with bacteria, complement system is activated and coat sprouts that make it easier for phagocytes to absorb them. What are the important organs are important for the immune system? Thus, bodies are important for immunity thymus, bone marrow, liver, spleen, lymph nodes and blood. Tonsils also important as they keep in their lymphocytes. Last Updated: 03/26/2011 >>. <<
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