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Role of B cell receptor Igα and Igβ subunits in MHC class II-restricted antigen presentation

1995; Cell Press; Volume: 3; Issue: 3 Linguagem: Inglês

10.1016/1074-7613(95)90118-3

1097-4180

Christian Bonnerot, Danielle Lankar, Daniel Hanau, Danièle Spehner, Jean Davoust, Jean Salamero, Wolf H. Fridman,

Immune Cell Function and Interaction

The ability of the B cell antigen receptors (BCRs) to enhance MHC class II-restricted antigen presentation was ascribed to mig-associated Ig alpha/Ig beta heterodimers. The relative role of Ig alpha and Ig beta subunits in antigen presentation was investigated by fusing their cytoplasmic tails to the extracellular and transmembrane domains of Fc receptors. Ig alpha and Ig beta chimera mediate antigen internalization and increase the efficiency of antigen presentation, but they drive antigens to different endosomal compartments. Furthermore, antigens internalized by either chimera are degraded and presented with different kinetics. The cytoplasmic tail of Ig alpha targets antigen towards a major population of newly synthesized MHC class II located in class II-rich compartments. In contrast, Ig beta targets antigen towards a minor population of recycling MHC class II molecules, located in transferrin receptor-containing endosomes. Altogether, our data indicate that the composition of BCR could be therefore an important way to modulate the immune response.