BPRC Research | Immune System | What does it do?
The immune system is designed to be able to distinguish between self and non-self. It is then designed to make “made to measure” responses against the non-self (the pathogen) that accurately kill the pathogen, but leave the self untouched. It does this by recognising the molecules of the pathogen and designing other molecules that fit like a lock and key with only the pathogen molecules. These “designer made” molecules carry with them the tools to kill the pathogen.
The pathogen molecules come in millions of different types. To combat this problem the immune system is extremely complex, and highly efficient so that it can nearly always design new locks to fit these keys. One downside to this efficiency is that each immune system is so finely tuned that it even sees the cells from another person as foreign. That is because our cells carry very small molecular differences from person to person. The immune system is so sensitive that it sees these differences. This means that transplantation of organs to save lives is very complicated. Another problem, due to the complexity of the immune system, is that it sometimes runs out of control and attacks its own body. This is called autoimmunity, and is the cause of a number of very serious diseases.
The components of the immune system all start from “stem cells” in the bone marrow. These stem cells are very flexible, and can develop into many different cell types. Some may grow into the cells that make special molecules called antibodies, or they may grow into special cells, called T-cells, which patrol your body looking for foreign invaders. Some of these patrolling cells have the task of controlling and helping the immune response, and some have the task of binding to the pathogen and killing it.
What we have learned over the past few years is that the business of identifying non-self is very complex indeed. You can consider your immune system as an organ of your body, just as your heart or your brain, except it is spread over your whole body. It has to be spread, because the pathogens can attack from anywhere (skin, lungs, intestines, etc.). However, the problem with it being spread everywhere is how do you keep the immune system organised?