In our immune system, how do the cells (whichever ones are appropriate) recognize and store the information of previous pathogens, and where in the body is that information stored?

Question

Follow up: Does that information deteriorate or do these cells ‘forget’?

Edit: If you’re able to answer the question, but can’t ELI5, then maybe explain in a way that a lay-person would understand i.e. not jargon-heavy.

In: Biology

Answer 1

The entire process is quite complex and does not fit in the format of this subreddit. But a very simplified answer is that the body produces a type of cells called B-cells. Each of them have an antigen associated with it with a random marker. However if the marker triggers on the stem cell that created the B-cell it is deleted so that only B-cells that react to proteins that your body can not make is every being made. This does mean that technically you have some antibodies against every possible virus and bacteria ever. But these are in too small numbers to do anything. But when a B-cell gets a match it will alert the rest of the immune system such as the T-cells to the intruder, start making more copies of the antibody and multiply itself so it can go hunt for more intruders. These B-cells will linger around in your blood stream for long after the infection is over. However as with any cells they do have a limited lifespan and will die. And if there have not been any other infections of the same type they will not have made more of the same cells.