Neutrophils are our body's first line of defense against bacterial infections. These cells can recognize certain chemicals and move to the source of these "chemoattractants" by migrating up the chemical concentration gradient or "toward the smell". The neutrophils were placed in a gradient of fMLP (n formyl methionine- leucine- phenylalanine), a peptide chain produced by some bacteria that is used by the neutrophils to find infecting organisms. The cells charge out like a "posse" after the bad guys. --- Finest quality science clips: http://www.FreeScienceClips.com --- Notice: This video is copyright by its respectful owners. The website address on the video does not mean anything.