Hahaha, I, a pathogen, have successfully managed to get past the first line of defence, the skin! Since I entered from the foot, I don't need to worry about eyelashes or tears!
Not so fast! We Neutrophils, Macrophages and Monocytes are immediately beginning phagocytosis!
Don't mind me, I'm just a Helper T cell looking for antigens! There's one!
We're antibodies, proteins that recognize foreign substances and act to neutralize or destroy them! Thanks to the Helper T cell, we were able to do our job!
And don't forget us, the Killer T cells and Suppressor T cells, which destroy the infected cells, and slow and suppress the process of cellular immunity! (Respectively)
Whew, I've been sick for days, but I feel much better now! Thanks to my immune system and its three layers of defence, I'll be A-Ok. The first layer was skin, which prevented at least a portion of pathogens from entering, the second was non-specific defences, where white blood cells use phagocytosis, and lastly, specific defence, where antibodies ensure I'll be safe from future attacks and recognize any of the pathogens I was exposed to!