3-D Representation from TB Tubercle (IMAGE) University of Washington Caption This is a 3-D representation of a zebra fish TB tubercle mounted and stained to show MMP9 (green) and macrophages (red). Detailed microscopy of the MMP9-producing cells showed that they are epithelial cells surrounding the TB infected macrophages. This image is from a study that suggests that epithelial cells are not bystanders, but are co-opted by the TB bacteria to produce MMP9 and to play a central role in forming tubercles that then benefit the TB bacteria. Credit J.M. Davis and T. Pozos Usage Restrictions For use only by news media and educational institutions, including museums. 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.