Cutting edge: Differential sequestration of plasma membrane-associated B cell antigen receptor in mature and immature B cells into glycosphingolipid-enriched domains

Glycosphingolipid-enriched domains (GEDs) are believed to act as platforms for transduction of B cell Ag receptor (BCR)-induced signals from the cell surface. We sought to study whether differential sequestration of BCR into GEDs may contribute to the described intrinsic signaling differences betwee n mature and immature B cells. In this study we found that mature B cells c opolarize the BCR with GEDs following BCR aggregation, whereas transitional immature B cells do not. Although anti-BCR treatment leads to receptor agg regation by immature stage B cells, the aggregated complexes do not colocal ize with GEDs. We found this difference to be independent of the isotype of the receptor, thereby associating this difference in BCR-GED colocalizatio n to the developmental stage of the B cell. These findings suggest a struct ural basis for the developmentally regulated differences observed in Ag rec eptor-mediated signal transduction.