EXPRESSION OF THE LYMPHOTOXIN BETA-RECEPTOR ON FOLLICULAR STROMAL CELLS IN HUMAN LYMPHOID-TISSUES

The lymphotoxin beta receptor (LT beta R), and its ligand, LT alpha 1 beta 2, have been proposed to play a key role in the development and o rganization of lymphoid tissues. The LT beta R is expressed on a varie ty of human primary and transformed cells, but strikingly absent on T or B lymphocytes and primary monocytes or peripheral dendritic cells, although LT beta R is detected on some myeloid leukemic lines. In the developing thymus LT beta R is prominent along the trabeculae and into the medulla upto corticomedullary junction. In the spleen, LT beta R is prominently expressed by cells in the red pulp and along the border s of red and white pulp which colocalizes with reticular stromal cells . The LT beta R is expressed on a human follicular dendritic cell line , FDC-1, and signals expression of CD54 when ligated with the LT alpha 1 beta 2 complex. These results support the concept that directional interactions between LT alpha 1 beta 2 bearing lymphocytes and LTPR be aring stromal cells are involved in the organization of lymphoid tissu e.