The Japanese cast includes Tomoaki Maeno as White Blood Cell (Neutrophil), Kana Hanazawa as Red Blood Cell (Erythrocite), Kikuko Inoue as Macrophage, Daisuke Ono as Killer T Cell, Maria Naganawa as Platelet, Takahiro Sakurai as Helper T Cell (T Lymphocyte), Saori Hayami as Regulatory T Cell, M.A.
The series was directed by Kenichi Suzuki based on the series composition by Yuuko Kakihara.
Takahiko Yoshida handled the character design and served as the chief animation director with the animation produced by David Production.