Résumé
The canonical form of the B cell antigen receptor is composed of membrane immunoglobulin sheathed by the
α
β
heterodimer. Whereas membrane IgM cannot be transported to the cell surface in the absence of
α
β
, both IgD and IgG2b can be expressed naked (i.e. without
α
β
) on the surface of myeloma transfectants. In the case of one cell-line, such naked IgD has been shown to be inserted into the membrane by a glycosyl-phosphatidylinositol anchor. Here, however, we show that both IgD and IgG2b (but not IgM) can be expressed on the surface of myeloma transfectants without either sheath or anchor. This distinction between the isotypes is attributabutable to differences in the region of the transmembrane segment.