Lymphocyte Cells in Thymus (IMAGE) Instituto Gulbenkian de Ciencia Caption Microscopic image of a thymus section. Mature T lymphocytes (red and green) are at the centre of the thymus whereas the precursor cells (yellow) are located at the periphery. Credit Mariana Ávila, IGC. Usage Restrictions This image can only be used to illustrate this news item. 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.