The adhesion molecules, l-selectin and sialyl lewis x, relate to the formation of the follicular dendritic cell-lymphocyte cluster in the mantle zone.

The follicular dendritic cell (FDC)-lymphocyte cluster is rich in the follicular light zone of the secondary lymphoid follicles (LFs). Although, the mantle zone (MZ) also has FDC-lymphocyte cluster, it has not known about what kind of adhesion molecules relates to cluster formation. In the present study, we investigated whether the adhesion molecules, L-selectin (CD62L) and sialyl Lewis x (CD15s) can mediate the formation of the cluster in human tonsillar LFs. The MZ only expressed both the adhesion molecules in the secondary LF. Isolated FDC-lymphocyte clusters were composed of CD62L(+) lymphocytes and CD15s(+) FDCs. Stamper-Woodruff binding assay revealed that the binding of IgD(+) lymphocytes was significantly inhibited by pretreatment with anti-CD62L antibody or with anti-CD15s antibody. These results indicate that CD62L on MZ lymphocytes and CD15s on FDCs may play a role of the cluster formation, unlike the clusters in the other parts of LFs.