Answer: leukocytes

AnswerCrossword Clue
leukocytesA colorless cell that circulates in the blood and body fluids and is involved in counteracting foreign substances and disease; a white (blood) cell. There are several types, all ameboid cells with a nucleus, including lymphocytes, granulocytes, monocytes, and macrophages
leukocytesLEUKOCYTE, a colorless corpuscle, as one of the white blood corpuscles also LEUCOCYTE