White blood cells

minuscule bodies in the blood whose job it is to fight germs

White blood cells or leukocytes are cells of the immune system which defend the body against both infectious disease and foreign materials. Several different and diverse types of leukocytes exist, but they are all produced and derived from a multipotent cell in the bone marrow known as a hematopoietic stem cell. Leukocytes are found throughout the body, including the blood and lymphatic system.
See more at Wikipedia.org...

White blood cells (WBCs) are cells which circulate in the blood and lymphatic system and harbor in the lymph glands and spleen. They are part of the immune system responsible for both directly (T cells and macrophages) and indirectly (B cells producing antibodies) attacking foreign invaders of the body.