title: The introversion of the immune response: a hypothesis for T-B interaction.
abstract: B cells present specific antigen efficiently(1-3) and, like macrophages, internalize antigen before apparently presenting it in association with class II MHC molecules. The association seems to occur when antigen bound to surface immunoglobulin (sIg) is internalized in a vesicle containing class IIMHC molecules(4). sIg is partly degraded in the vesicle and not re-expressed in native form' but class II molecules are re-expressed(6). Class II molecules have little or no polymorphism. How can they associate with all antigens in such a way that T helper cells can recognize the complex? Here Lee Leserman offers a solution to this problem based on the suggestion that T cells recognize the Ig in a complex of associated Ig and class II molecules, rather than the antigen in an antigen-class II complex. The system is antigen-dependent, not because the antigen has to associate with class II molecules, but because antigen is necessary for the internalization of sIg which is required for sIg association with class II.
authors.affiliation: Centre d'Immunologie INSERM-CNRS de Marseille-Luminy, Case 906, 13288 Marseille cédex 9, France.
authors.forename: L
authors.initials: L
authors.lastname: Leserman