Natural Killer Cells (IMAGE) Florida State University Caption A microscope image of natural killer cells used in this Florida State University research. The purple circles show the cell nucleus and the red shapes show the cytoplasm. The FSU researchers showed the possibility of enhancing natural killer immune cells to improve their ability to attack a rare pediatric brain cancer. Credit Courtesy of Amy Sang Usage Restrictions This image may be used with appropriate caption and credit. License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.