Human Tonsil Section (IMAGE) La Jolla Institute for Immunology Caption This is a fluorescence microscopy image of a human tonsil section. Activin A (in red) can be found in areas enriched in T lymphocytes (in green), where Tfh differentiation begins, and in close proximity with B cells and germinal centers (in blue), areas where fully differentiated Tfh cells interact with B cells to help them producing high-quality antibodies. Credit Courtesy of Dr. Michela Locci and Dr. Zbigniew Mikulski, La Jolla Institute for Allergy and Immunology Usage Restrictions None 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.