B cell (IMAGE) Keck School of Medicine of USC Caption Adaptive immune cells, such as B cells (pictured), are a key component of a youthful immune system. Credit Image courtesy of the National Institutes of Allergy and Infectious Diseases Usage Restrictions Credit must be given to the creator. License CC BY 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.