Humoral Immunity is the world of antibodies and non-cellular means of killing foreign agents within the body. An antibody is generally specific to the thing being attacked. It's called having antigen-specificity. For example, you never got the red measles twice. It's impossible. Why?
Because, either through vaccination or actually having the disease, you made antibodies to the specific virus causing the measles. The measles virus was the "antigen" which signaled the making of the antibody which was made against only that virus. Finally, long lasting cells inside your body kept that specific memory alive so that antibodies to the measles could always be created immediately in the event of an exposure later in life. It's a pretty good system; we have antibodies against practically anything we have ever been exposed to and fought off in our entire life.
Speaking of a pretty good system, the immune system is not perfect. It can go overboard, get misdirected and make antibodies that attack things we are supposed to have in our body like our colon, our kidneys or our pancreas. It's the body's version of mistaken identity. Unfortunately that mistaken identity leads to autoimmune diseases that destroy our own body systems. There are hundreds of autoimmune diseases that can cripple those who get them. Some common autoimmune conditions are as follows:
Allergies, too, are cases of mistaken identity. People who have allergies make antibodies to things in the environment that don't bother most other people. A person who has allergies, for some reason, often develops allergies for multiple things. Similarly, those with autoimmune diseases are at risk for developing other autoimmune conditions on top of the ones they already have.
Cellular Immunity or Cell-Mediated Immunity
Cell mediated immunity begins where everything in the immune system begins-in the bone marrow. The bone marrow makes nearly all of the components of the blood. It's a complicated system but, for the purposes of talking about cell-mediated immunity, let's discuss the formation of lymphocytes, the key players in this kind of immunity. Bone marrow-based stem cells form two kinds of lymphocytes, T-lymphocytes and B-lymphocytes.
You already know about B-lymphocytes but you don't know it yet. These are the cells that grow up to be plasma cells. When plasma cells are given a specific signal or antigen (the name we give for something that triggers an antibody response), they make antibodies-lots of them. We already know how the antibody binds to the offending cell or invader and causes it to leak or become destroyed by phagocytes.
Speaking of offending cells, did you know you probably make cancer cells in your body all the time? Fortunately for you and your immune system, almost all of these cells are recognized as foreign agents and are destroyed before they can create any bodily damage. When are immune system fails us, cancer cells can take off and actually create one of the conditions we know as "cancer". This is one good reason why it is so important to maintain a healthy immune system. To continue to part 3 click here.