pH dependence of the interaction between immunogenic peptides and MHC class II molecules. Evidence for an acidic intracellular compartment being the organelle of interaction

TY - JOUR

T1 - pH dependence of the interaction between immunogenic peptides and MHC class II molecules. Evidence for an acidic intracellular compartment being the organelle of interaction

AU - Mouritsen, S

AU - Buus, Anette Stryhn

AU - Petersen, B L

AU - Buus, S

N1 - Keywords: Amino Acid Sequence; Histocompatibility Antigens Class II; Humans; Hydrogen-Ion Concentration; Molecular Sequence Data; Peptide Fragments; T-Lymphocytes

PY - 1992

Y1 - 1992

N2 - The pH dependence of the interaction between immunogenic peptide and MHC class II was studied both in a direct biochemical binding assay and in a functional Ag presentation assay. The two approaches yielded similar results. All of the peptides tested bound optimally to their relevant MHC class II restriction element at around pH 4.5. Indeed, several of the peptides did not bind at neutral pH. These results demonstrate that Ag under physiologic conditions meet MHC class II in a quite acidic environment. The very acidic pH optimal for peptide-MHC class II interaction is only found intracellularly and most notably in the endosome-lysosome compartment in which Ag processing is thought to occur. Thus, Ag processing and interaction with MHC class II molecules can potentially happen in the very same compartment. This yet undefined acidic compartment would have to contain proteolytic enzymes and MHC class II molecules.

AB - The pH dependence of the interaction between immunogenic peptide and MHC class II was studied both in a direct biochemical binding assay and in a functional Ag presentation assay. The two approaches yielded similar results. All of the peptides tested bound optimally to their relevant MHC class II restriction element at around pH 4.5. Indeed, several of the peptides did not bind at neutral pH. These results demonstrate that Ag under physiologic conditions meet MHC class II in a quite acidic environment. The very acidic pH optimal for peptide-MHC class II interaction is only found intracellularly and most notably in the endosome-lysosome compartment in which Ag processing is thought to occur. Thus, Ag processing and interaction with MHC class II molecules can potentially happen in the very same compartment. This yet undefined acidic compartment would have to contain proteolytic enzymes and MHC class II molecules.

M3 - Journal article

C2 - 1538129

SN - 0022-1767

VL - 148

SP - 1438

EP - 1444

JO - Journal of Immunology

JF - Journal of Immunology

IS - 5

ER -