T Cells: The Natural Killer Cells that Help Your Immune System
As complex and as amazing as your immune system is, right now there is a bacteria or virus developing that is very harmful. Often the invader will enter the body and go largely unnoticed. Fortunately the body has a way of dealing with these invaders. Lymphocytes are cells which help the immune system adapt to an invader that it has never seen before.
The process starts with the phagocyte that stumbled upon the invader. While ingesting the enemy infiltrator, the phagocyte saves a few important features of the enemy. These features are called "antigens". The phagocyte presents these antigens to another cell in the immune system called a T lymphocyte or "T helper cell". These helper cells pass on information about the invading bacteria or virus to another type of lymphocyte called "B cells". These B cells are capable of secreting antibodies. Antibodies are like guided missiles that carry attacking receptors which are designed to destroy the invading bacteria or virus.
Once the T and B cells reproduce, the immune system gears up for battle. Antibodies swarm to the invader and attach themselves. Millions of proteins are then synthesized by the presence of the antibodies. These proteins also attach themselves to the invading pathogen. These proteins help to destroy the enemy by drilling holes into the pathogen''s dell wall which virtually disintegrates the invader. Killer T cells then join in the fight. T killer cells also carry the receptor capable of recognizing the enemy. Instead of producing antibodies though, they simply attach themselves to the invader and attack its cell membrane by punching holes into it, much as proteins do. T killer cells also attack the body''s damaged or cancerous cells when they arise.
One week after the war has begun, the cells of the immune system are in high gear, dividing, metabolizing and secreting immunological chemicals and antibodies at an incredibly rapid pace. Once the enemy has been destroyed, another group of T cells (called "T suppressor cells")sends out chemical signals that gradually turn down the immune response and allow the body to return to its normal state.
What is very interesting is that special memory cells from both the immune-regulating T cells and the antibody producing B cells record all the events of the war that has occurred within the body. They then circulate throughout the body and are ready to mount a quick defense should the same invader return. Hence, your immune system has now strengthened.
For more information, see this tutorial from the National Cancer Institute that illustrates the immune system, complex network of specialized cells and organs that distinguishes between self and foreign molecules inside the body. The presentation also explains that a malfunctioning immune system can cause allergies or arthritis and can fail to stop the growth of cancer cells.
The Immune System - Slide Number and Title