Expression of the lymphotoxin β receptor on follicular stromal cells in human lymphoid tissues

The lymphotoxin β receptor (LTβR), and its ligand, LTα1β2, have been proposed to play a key role in the development and organization of lymphoid tissues. The LTβR is expressed on a variety of human primary and transformed cells, but strikingly absent on T or B lymphocytes and primary monocytes or peripheral dendritic cells, although LTβR is detected on some myeloid leukemic lines. In the developing thymus LTβR is prominent along the trabeculae and into the medulla upto corticomedullary junction. In the spleen, LTβR is prominently expressed by cells in the red pulp and along the borders of red and white pulp which colocalizes with reticular stromal cells. The LTβR is expressed on a human follicular dendritic cell line, FDC-1, and signals expression of CD54 when ligated with the LTα1β2 complex. These results support the concept that directional interactions between LTα1β2 bearing lymphocytes and LTβR bearing stromal cells are involved in the organization of lymphoid tissue.