(IMAGE) Helmholtz Centre for Infection Research Caption The picture shows attenuated tuberculosis bacteria, enclosed by macrophages, the scavenger cells of the immune system. Credit MPI for Infection Biology - CF Microscopy / Volker Brinkmann Usage Restrictions You may use this picture if attributed as indicated. 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.