Anti-peptide antibody blocks peptide binding to MHC class I molecules in the endoplasmic reticulum
Department of Pathology
ATP-Binding Cassette Transporters; Animals; Antibodies, Blocking; Antibodies, Monoclonal; Antigen Presentation; B-Lymphocytes; Binding Sites, Antibody; Binding, Competitive; Cell Line; Diffusion; Egg Proteins; Endoplasmic Reticulum; Female; H-2 Antigens; Hybridomas; Mice; Mice, Inbred C57BL; Ovalbumin; Peptide Fragments; Tumor Cells, Cultured
Life Sciences | Medicine and Health Sciences
The finding that MHC class I molecules are physically associated with the TAP transporter has suggested that peptides may be directly transported into the binding groove of the class I molecules rather than into the lumen of the endoplasmic reticulum (ER) where they subsequently would encounter class I molecules by diffusion. Such a mechanism would protect peptides from peptidases in the ER and/or escaping back into the cytoplasm. However, we find that an anti-peptide Ab that is cotranslationally transported into the ER prevents TAP-transported peptides from being presented on class I molecules. The Ab only blocks the binding of its cognate peptide (SIINFEKL) but not other peptides (KVVRFKDL, ASNENMETM, and FAPGNYPAL). Therefore, most TAP-transported peptides must diffuse through the lumen of the ER before binding stably to MHC class I molecules.
Rights and Permissions
Citation: J Immunol. 2001 Mar 15;166(6):3952-6.