S. Morkowski et al., Peptide loading in the endoplasmic reticulum accelerates trafficking of peptide : MHC class II complexes in B cells, J BIOMED SC, 6(1), 1999, pp. 53-63
In a combination of biochemical and immunoelectron-microscopical approaches
we studied intracellular trafficking and localization of the endoplasmic-r
eticulum (ER)-formed complexes of murine MHC class II molecule I-A(b) and a
n antigenic peptide E alpha 52-68 covalently linked to its beta-chain, The
association with the peptide in the ER leads to sharp acceleration of the i
ntracellular trafficking of the complexes to the plasma membrane. Within th
e cells, E alpha 52-68:I-A(b) complexes accumulate in the multivesicular MH
C class ii compartment (MIIC), but not in denser multilaminar or intermedia
te type MIICs, The changes in the trafficking of ER-formed complexes result
solely from the presence of the tethered peptide, since wild-type class II
molecules traffic similarly in bare lymphocyte syndrome cells and in wild-
type antigen-presenting cells.