DISRUPTED SPLENIC ARCHITECTURE, BUT NORMAL LYMPH-NODE DEVELOPMENT IN MICE EXPRESSING A SOLUBLE LYMPHOTOXIN-BETA RECEPTOR-IGG1 FUSION PROTEIN

Early in ontogeny, the secondary lymphoid organs become populated with numerous cells of mesodermal origin which forms both the lymphoid and stromal elements. The critical receptor/ligand interactions necessary for lymphoid organogenesis to occur are for the most part unknown, Al though lymphotoxin-alpha (LT alpha) has been shown to be required for normal lymph node, Peyer's patch, and splenic development, it is uncle ar if soluble LT alpha 3, and/or cell-bound lymphotoxin-alpha beta (LT (YP) mediate these developmental events. Here we report that blocking LT alpha beta/lymphotoxin-beta receptor (LT beta R) interaction in viv o by generating mice which express a soluble LT beta R-Fc fusion prote in driven by the human cytomegalovirus promoter results in an array of anatomic abnormalities affecting both the spleen and Peyer's patches, but not the lymph nodes. These results demonstrate that surface LT al pha beta ligand plays a critical role in normal lymphoid organ develop ment.