The Assembly of Functional Β2-Microglobulin-Free MHC Class I Molecules That Interact With Peptides and CD8+ T Lymphocytes
Functional MHC class I molecules are expressed on the cell surface in the absence of β2-microglobulin (β2m) light chain that can interact with CD8+ T lymphocytes. Whether their assembly requires peptide binding and whether their recognition by CD8+ T lymphocytes involves the presentation of peptide epitopes remains unknown. We show that β2m-free H-2Db assembles with short peptides that are ∼9 amino acid residues in length, akin to ligands associated with completely assembled β2m+ H-2Db. Remarkably, a subset of the peptides associated with the β2m-free H-2Db has an altered anchor motif. However, they also include peptides that contain a β2m+ H-2Db binding anchor motif. Further, the H-2Kb- and H-2Db-restricted peptide epitopes derived from SV-40 T antigen also assemble with H-2b class I in β2m-deficient cells and are recognized by epitope-specific CD8+ T lymphocytes. Taken together our data reveal that functional MHC class I molecules assemble in the absence of β2m with peptides and form CD8+ T lymphocyte epitopes.
Schell, T. D.; Mylin, Larry M.; Tevethia, S. S.; and Joyce, S., "The Assembly of Functional Β2-Microglobulin-Free MHC Class I Molecules That Interact With Peptides and CD8+ T Lymphocytes" (2002). Biology Educator Scholarship. 59.