More about T-cells and B-cells that protect your body from invaders

Our immune system is one of nature’s most fascinating inventions of our body.  It protects us against billions of bacteria, viruses, parasites and fungi with ease.  Most of us never reflect upon the fact that while we hang out with our friends, go shopping, or go to school, our immune system is constantly on the alert, attacking whatever invaders coming through our skins, mouth, ears, eyes, and also attacking those critters that are multiplying inside our body.

A little info about how they are formed.  There are cells called White blood cells in every human body called lymphocytes, these White blood cells originate in the bone marrow but migrate to parts of the lymphatic system such as the lymph nodes, spleen and thymus.    The lymphatic system also involves a special transportation system – lymph vessels – mainly for transportation and storage of lymphocyte cells within the body.  The lymphatic system feeds cells into the body and filters out dead cells and invading organism such as bacteria.  There are two main types of lymphatic cells, T-cell and B-cells.  As informed earlier, T-cells come in two different types, helper cells and killer cells.  They are called T-cells after the thymus, which is an organ situated under the breastbone.  T-cell produced in the bone marrow and later move to the thymus where they mature.  B-cells are continuously produced in the bone marrow from where they migrate to secondary lymphoid tissues where some develop into mature B cells.

Apart from the T-cells and B-cells and their subset cells.  There is a cell called plasma cell which are derived from B-cells.  The role of the plasma cells is in producing a specific protein, called an antibody that responds to antigen.  Antibodies are released from the plasma cell so that they can seek out invaders and help destroy them.  Plasma cells produces antibodies that too at an amazing rate and that release tens of thousands of antibodies per seconds.  Antibodies trap invading viruses or bacteria in large clumps.  This makes it easy for the macrophages to eat them.  Antibody coated viruses are called “neutralized”, they are so called because they cannot infect your cells, as even after you have fought off your infections, some antibodies stay in your blood.

Introduction to Immune System – 4 – You can get back your health even if it has reached cancer stage

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Now, the T-cells can also call up the B-cells to join in their fight against the invaders, depending on the type of germs and depending other factors at play during invasion, the B-cell is very important because it can not only trap but also  mark the germs that haven’t yet infected a cell.  The B-cell shoots out antibodies, which is like a net.  These nets are called immunoglobulins and they look to us like the letter “Y”.  The germs are caught in the fork of the “Y” and neutralized so they are not able to infect your body.  Just like the killer T-cell, the B-cell will make more and more copies of itself in your lymph nodes before it heads to the infection site.  When we feel swollen lymph nodes, it’s because our activated B-cell and T-cells are making armies to fight against the invaders.

When all germs are destroyed, the battle is over and the area of cut is healed completely.  The T-cells and B-cells go back to your lymph nodes, and wait for signals of any other invaders.  Also the macrophage returns to patrol the skin, looking for new infections.  Now the T-cells and B-cells have fought the infection in the skin now and have experience of fighting those specific germs that invaded through the cuts and now they have information about that specific germs stored in the cells for future battle when required and these cells are called Memory cells.  These memory cells give your body a great advantage if you get infected by the same germs and the T-cells and B-cells get a huge head start and can build their cell armies in half the time during the next germ invasion.

An important difference between T-cells and B-cells is that B-cells can connect to antigens right on the surface of the invading virus or bacteria, while T-cells can only connect to antigens from the outside of the infected cells.

The human’s Acquired Immune System, mainly the T-cells and B-cells are responsible for the destruction of foreign particles once they enter the body.  Before it has seen a foreign particle, it is actually quite ignorant about how to destroy it.  During the first exposure to an invader, the acquired immune system must learn how to attack and destroy the foreign particles, for keeping out things it has never encountered before, hence once the acquired immune system has created a response, a protective response can be made more quickly and with greater force, allowing it to protect the body from harm.  You need to know that apart from T-cells and B-cells, there are also other important part of the acquired immune system that comes to play when required.

Introduction to Immune System – 3 – You can get back your health even if it has reached cancer stage

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In the beginning of the infection at the cut site, all invaders are treated the same.  Macrophages eat individual germs.  If the number of invaders are very small most of the time the macrophages can take care of it on its own.  This stops a major infection from starting but usually when they are not able to destroy all the germ invaders, they get the help from other cell defenders.  After macrophage eats up a germ, it takes the most unusual pieces of the germ, called antigens.   The macrophage now needs to report its findings and the unusual pieces to a dendritic cell that is patiently waiting inside the lymph for such an eventuality.  Note that communication of such information are very quick within the body.  This dendritic cell then takes the antigen, like ID tags from the macrophages and reports the information to the inactivated helper T-cells and B-cells.   The T-cell then activates and makes more and more copies of itself.

 

The first defender, the T-cells, is a type of T-cell which is called the helper and it acts like a ‘commander’ of your immune system army.  It normally knows what kind of invader it’s dealing with.  It decides whether a war is needed and how strong and thus the T-cell activates into a full-fledged commander.  A plan of action will be made.  Sometimes the danger is great.  During times like these, the body has another special fighters, just like wrestlers come in different age and weight classes to match an opponent, some T-cells are made for certain germs.  The special fighter T-cells in your immune system are called killer T-cells.  The helper T-cells go into the lymph node and find the one killer T-cell that matched to the invader and call them into the fight.  Thereafter, these cells activate and jump into action and follow the patch of cytokines to the injury and begin the full-scale attack against the germs.  The activated killer T-cells scans all the skin cells around the cut and try to find the special antigen that marks invader cells.  The antigen can even alert them to the invader if it’s hiding inside of one of your skin cells.  Once the antigen is found near the cut site, these killer T-cells shoot out cytotoxins that immediately destroy the antigen and any skin cell it has infected.  Thereafter, the macrophage then comes and gobbles up the dead, germ-filled skin cells and keep your system clean.

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The lymphatic system has a special route through which immune cells can move around the body.  The major parts of this system included the lymph nodes, the thymus, spleen, tonsils, and bone marrow.  In these organs, immune cells grow, multiply, or are recycled, keeping the immune system running.  Lymphatic vessels alongside your veins delivering immune cells throughout the body