TBO-FILGRASTIM IS A HUMAN GRANULOCYTE COLONY-STIMULATING FACTOR (G-CSF) PRODUCED BY RECOMBINANT DNA TECHNOLOGY. TBO-FILGRASTIM BINDS TO G-CSF RECEPTORS AND STIMULATES PROLIFERATION OF NEUTROPHILS. G-CSF IS KNOWN TO STIMULATE DIFFERENTIATION COMMITMENT AND SOME END-CELL FUNCTIONAL ACTIVATION, WHICH INCREASES NEUTROPHIL COUNTS AND ACTIVITY.