Ras Protein and Cells (IMAGE) American Friends of Tel Aviv University Caption Ras proteins tagged with green flourescence protein transfer from B (cancer) cells to NK (immune) cells. Credit AFTAU Usage Restrictions None License Licensed 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.