Facts About Our Immune System

Let’s face it; most of us usually appreciate our immune system only when we’re sick and disregard its importance otherwise. But it is actually very important, with its main purpose to protect our body with various types of cells that are interdependent of each other from never ending attacks of viruses, microbes, and pathogens.

These different cell types have their own characteristics, mechanisms and specialized functions; detecting foreign antigens and signaling the production of antibodies and killer cells to engulf these antigens and neutralizing it. Some of these cells also have a ‘memory’ that remembers what type of mechanism specified for certain infection so it always ready whenever the recognized infection comes back. That’s why most of us don’t get chickenpox twice.

The most outer part of our immune system is our own tough skin, serves as a first barrier between the hovering germs and inside of our body. There are other several barriers to protect us from getting diseases which is mechanical (like our skin), chemical; where our body secretes antibacterial fluids to kill bacteria such as saliva, tears and even breast milk, and biological barrier; where our diverse cells comes into action as the antigens gets into our body. If it does so, then they have to deal with the higher level of immune system that comprises of some of the components:

• Lymph nodes are found throughout the body; functions as an immunologic filter for the body fluid known as lymph
• Our lymph system composed mostly of T cells, B cells, dendritic cells and macrophages
• Antigens are filtered out of the lymph in the nodes before returning the lymph to the circulation
• The macrophages and dendritic cells that capture antigens present these foreign materials to T and B cells, consequently initiating an immune response, killing the antigens

Bone Marrow

• All the cells of the immune system are initially derived from the bone marrow. It produces B cells, natural killer cells, granulocytes and immature thymocytes, apart from red blood cells and platelets. These cells are produced through a process called hematopoiesis
• During hematopoiesis, bone marrow-derived stem cells differentiate into either mature cells of the immune system or into precursors of cells that migrate out of the bone marrow to continue their maturation elsewhere in our body

White Blood Cells

• Also known as leukocytes, they are produced or stored in many locations in the body, including the thymus, spleen, and bone marrow. The white blood cells are divided into granulocytes, lymphocytes, and monocytes
• Lymphocytes start out in the bone marrow and either stay there and mature into B cells, or they leave for the thymus gland, where they mature into T cells
• These white cells circulate through the body between the organs and nodes via lymphatic vessels and blood vessels
• In this way, the immune system works in a coordinated manner, acting like a ‘supervisor’ to our body for germs or substances that might cause problems
• B lymphocytes and T lymphocytes have separate functions: B lymphocytes are like the body's military intelligence system, seeking out their targets and sending defenses in the form of antibodies to lock onto them. T cells are like the soldiers, destroying the invaders that the intelligence system has identified

Antibodies

• B lymphocytes to produce antibodies, specialized proteins that lock onto specific antigen
• Antibodies continue to exist in a person's body but not capable of destroying it without help of other immunological components

Complement System

• The complement system is a biochemical cascade that attacks the surfaces of foreign cells. Consists of 20 different proteins and is named for its ability to “complement” the killing of pathogens by antibodies
• Response is activated by the complement binding to antibodies that have attached to these microbes or the binding of complement proteins on the microbes’ surfaces. This recognition signal triggers a rapid killing response
• The cascade results in the production of peptides that attract immune cells, and engulf the surface of a pathogen and starts the killing processes. This deposition of complement can also kill antigens directly by disrupting their plasma membrane

Our immune system is complex, interesting, and intelligent, doing all the hard work to keep our body healthy and free from infections. If we don’t take a proper care of our immune system, we’d suffer from 'immunodeficiency’ where we’re much more vulnerable to antigens. This can be fatal as it’s much harder to get cured even it’s just getting some minor flu.

Take a good care of your immune system, and it will take care of you.