Food Poisoning
S1, E4: Bacteria appear near the stomach. White Blood Cell (Neutrophil) is on the scene at once. There, he finds Eosinophil, another type of White Blood Cell, already in battle.

S1, E4: Bacteria appear near the stomach. White Blood Cell (Neutrophil) is on the scene at once. There, he finds Eosinophil, another type of White Blood Cell, already in battle.