Question: How does your body destroy pathogens?

Duncan Gaskin answered on 13 Mar 2013:

This is a really good Q and it is hard to keep it simple, but I’ll try. First your body has to recognise that it is a pathogen and not a good bug in your body. It does this in a couple of ways: if the bug causes damage to cells then the defences are activated, also the body has special cells that recognise the shapes of bad bugs and react if they meet them – some produce things called antibodies (see below)

So the next bit is destroying the pathogen. This also involves lots of different ways. There are things in your blood that can kill some bugs without needing to be activated, but lots of bugs have developed ways to avoid these. Next up are the antibodies, these are special proteins that recognise a pathogen and bind to it. This binding can sometimes kill the pathogen directly, but more usually the antibodies are recognised by other killing systems. There are special cells that move around your body looking for antibody coated things. When they find them they swallow them and destroy them. Some of these killer cells will swallow pathogens without antibodies. Some pathogens hide in your body’s cells to try and avoid this killer systems. But sometimes the cells they are hiding in put special markers on their surface and the killer cells come along and swallow the whole cell and pathogen.

Your body is fighting pathogens all the time and mostly you don’t know about it the systems are so good. If you get a spot then the white pus is a mix of the bacteria that cause the spot and the killer cells fighting them. The red around the spot is where the cells around the spot signal that they need more blood to bring the defence cells to the spot.

I hope this answers your question.

Cheers

Duncan