As this was the first time encountering this strain of the flu, the immune response takes time. During that time, the pathogen was able to cause symptoms that made Dawson sick. However, once the body fights off the infection, the memory cells created will make fighting the infection a second time much quicker.
Killer and Suppressor T Cells
On a tiring Monday morning, Mr. Bintner started excitedly explaining the plans for the coming week of classes. However, Dawson's evil clone, Dawson the Drooler, was in attendance for this class. The amazing student Dawson was focused on learning, but Dawson the Drooler was bored. Mr. Bintner thought it was a good idea to put the Dawsons together (for spacetime continuum stability), but it wasn't good for Dawson. Eventually, Dawson the Drooler fell asleep, slumped over Dawson. Dawson unmanned evil twin drools and snots all over his body. Bintner screams in terror as this happens. However, Dawson is not too worried because he remembered that he has a healthy immune system!
B Cells—Memory Cells
Damage to tissue triggers an inflammatory response. In this case, the damage was done by a sharp object (scissors). Basophil cells release heparin (an anticoagulant) and histamine to cause an inflammation response. This response has three stages. The first is dilation of the blood vessels. Blood vessels increase their diameter to increase blood flow to the breached area and allows defensive fluids (lymph) to enter the damaged tissues by increasing blood vessel permeability. The presence of extra fluids causes swelling and increased body temperature in that region.
The Next Week...
Dawson! How are you not-- I mean... it's great to see you again!
Yes, and it's all thanks to my amazing immune system!