Altered patterns of glycosylation on rat lymphocytes associated with activation

The expression of cell-surface carbohydrates on rat lymphocytes was investigated by flow cytometry using a panel of lectins. A small group of lectins was identified, all with a main binding requirement of N-acetylgalactosamine that bound to all B lymphocytes but only to activated T lymphocytes expressing the interleukin-2 (IL-2) receptor (as shown by staining with the monoclonal antibody OX39). Studies demonstrated that five of these lectins competed for the same binding site, while others did not. With the knowledge of the binding requirements of these lectins, a structure can be deduced for the carbohydrate moiety which appears on T lymphocytes when activated.