U-4989

 is a minor character in Cells at Work!.

He is a Neutrophil working under the Neutrophil Division and a close friend of U-1146, along with U-2001, U-2626 and U-2048. As a neutrophil, his purpose is to destroy bacteria invading the body.

Appearance
Like the other neutrophils, he has extremely pale skin and hair. His eyes are bigger than any other neutrophils. His short, fluffy hair does not cover his light eyes. He wears the all-white neutrophil uniform.

Personality
U-4989, though a competent fighter, seems naïve compared to his comrades. He is known for improvising weapons, and he once forgot to use his L-Selectin at an abrasion, causing him to almost fall to his death. He often appears bloodthirsty but is a kind and sensitive cell who loves his comrades deeply. He continually shows his concern toward U-1146's well-being and is touched, to the point of crying, by AE3803's goodwill toward white blood cells.

Trivia
U-4989
 * He once tied his knife to a stick, making a makeshift spear.
 * His code, 4989 (4=shi 9=ku 8=ha 9=ku), is pronounced similarly to the Japanese idiom 四苦八苦 (shikuhakku), which means having a hard time.