They need a cell to live in as they’re just a strand of DNA, and the throat cell contains everything it needs to live in ; food etc. As the virus feels comfortable in its environment, it starts to multiply. It makes thousands of copies of itself and eventually there are so many viruses in that one throat cell that it can’t hold them anymore and bursts. Alone from that cell, tens of thousands viruses escape and go on to infect other cells and produce even more viruses.
The body’s immune system has by now recognised what’s going on, and responds immediately. The Natural Killer Cells are always patrolling the body and when they recognise a virus they go on to killing it. They produce a chemical that they then use in battle : they give the virus a lethal burst of that chemical and in doing so, put a hole through its membrane. The viruses fluids leek out and the virus cell bursts. That’s how the Natural Killer Cells work. The only problem with them is that they also kill lots of healthy throat cells, making our throat go sore.(Sore Throat)
Another type of white blood cell are Macrophages or Phagocytes. They also react immediately to the virus. They engulf or “gobble up” the virus cell and digest it using the enzymes they contain. They also have the ability to attract other white blood cells to where the infection has taken place. Macrophages can release something called Interleukins if necessary. Our body temperature (inside our body) is 37 degrees Celsius. The viruses replicate best at this temperature. So what the interleukins does is increase the body’s temperature so it slows down the viruses replication. That makes us think that we are cold and we get a temperature.
The Natural Killer Cells and Macrophages are two white blood cells that can respond immediately to a virus. However, there are also two other white blood cells that have to be kind of “activated” to fight the virus. The cell who’s job is to activate them is called the Dendritic Cell. The virus has something all around it called antigen or virus spikes. The Dendritic Cell picks up lots of these Antigen and goes to the Lymph Glands with them, where the T and B cells are. There are millions of T and B cells in the Lymph Glands, each designed to fight and kill one particular virus. The Dendritic Cell presents the Antigen from the Virus to the T and B cells to see if it fits.
That looks like this :
When it has found the T and B cell that fits onto the antigen, which takes a long time as there are millions, the T and B-cells can finally roll into action.
The T-cells and B-cells start replicating to millions, and so our lymph glands swell. The T-cells go straight into the blood stream and to the site of infection. They bind to the infected cells and destroy them. The T-cells have also got helper cells whose job is to activate other T and B-cells, as well as Natural Killer Cells and Macrophages.
The B-cells don’t go to the site of infection, but instead make antibodies which bind onto the antigen of the virus and destroy it. However, the B-cells can’t make those antibodies on their own. They need large plasma cells to act as a factory for producing the antibodies. The antibodies are then also released into the blood stream and they go to the site of infection. They work like this :
Once the virus and the virus infected cells have been killed, most of the White Blood Cells die. Some stay alive though and act as Memory Cells, which make you immune to that particular virus because they’ll remember exactly how to fight it and not let it break out. So why do we still get flu’s then? Because the virus changes its antigens slightly so our Memory Cells don’t recognise it as the virus they already fought.
All the Macrophages don’t die either. They stay alive to eat the debris produced by all the cells that have died. The debris that doesn’t get eaten by the Macrophages are taken away by the cilia in our throat, then swallowed and digested. We also cough out the dead cells and debris.
So all these symptoms we get : Sore Throat, Temperature, Glands Swelling, being cold and coughing are just signs that our body’s immune system is reacting correctly to the virus.
