Little Timmy was on the way back home, when someone sneezed on him! Most of it landed on his skin, which he could quickly wipe off. But, some of it was able to get into his nose as he took a breath. While most of the pathogen will get caught in his 1st line of defense, the nose hairs and mucus, some will still get into his body.
Little Timmy arrives home and talks to his mom. His mom is the one responsible for his non-specific immunity. This is when the mom gives immunities to certain viruses from birth. Unfortunately, his non-specific immunity does not help against what he has.
The virus in little Timmy's body has infected lots of cells in his throat, making him sick. Timmy can rest and drink lots of water to feel better. But what is his body doing? His body is currently using the 2nd line of defense, the white blood cells. This is part of his specific defense, which will create antibodies.
Ugh, I don't feel so good.
Inside of Timmy's body, the T-cells (shown by the knight) is attacking the virus (shown by the monster) inside of an infected cell. The T-cells attack infected cells and cells around them. Before long, this cell and part of the virus will be no more. This requires lots of T-cells, to his neck will have inflammation. This will cause his throat to be red and hurt, but will allow more T-cells to come.
In the blood, the phagocytes/antigens (shown by the tiger) will eat pathogens and take them to B-cells (shown by person). The B-cells are important as they will then create antibodies that will be used to mark the virus for destruction.
After a few days, antibodies (shown by the arrow) will target the virus, and mark them for destruction. The last of the virus will be defeated and Timmy will feel well again! To also make sure Timmy doesn't get this virus again, the B-Cells have created memory cells that will stop the virus before it does any damage, should it come back.