Single Macrophage (IMAGE) University of California - San Diego Caption This micrograph shows a single macrophage, which is a type of cell in the immune system. In obesity-related inflammation, large numbers of these cells infiltrate adipose (fat) tissue, where they release signals that trigger various metabolic changes. Credit NIH/NIAID Usage Restrictions Use photo 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.