P2 - The importance of sialoglycans for lymphocyte development and function

Sialoglycans are abundant glycan structures on the surface of lymphocytes. They act as ligands for Siglec receptors or selectins, but also more general functions are discussed. Preliminary results demonstrate that sialoglycan expression seems to be crucial for the maintenance of B and T lymphocytes. Generation of mice with a B cell specific or T cell specific deletion of Cmas, a gene coding for a crucial enzyme in sialoglycan synthesis, demonstrated severe defects in their respective peripheral lymphocyte populations. Apparently, induction of apoptosis is involved in the loss of peripheral B or T cells lacking sialic acids. This project will address in detail the mechanisms of how the loss of sialoglycans from the surface of lymphocytes leads to lymphocyte defects. It will also be examined how B and T cell functions are altered upon the loss of sialoglycans. Sialoglycans attached to antibodies can modulate humoral immune responses. It will be addressed how complete loss of sialic acids on secreted antibodies affects immune responses.