Variation in H-2K(k) peptide motif revealed by sequencing naturally processed peptides from T-cell hybridoma class I molecules.
Class I major histocompatibility complex (MHC) molecules interact with a diverse array of self and foreign peptides, displaying them on the cell surface and providing an extracellular indication of intracellular invasion. The most clearly defined role for these class I/peptide complexes is to cause effector responses upon binding to antigen-specific receptors of cytotoxic T cells. We have characterized the mouse thymoma/rat V beta 8.2+ T-cell hybridoma C14/BW12-12A1 by fluorescence-activated cell sorting analysis and have used immunoaffinity chromatography to purify class I molecules from these cells. The peptides bound to the class I molecules were fractionated by high-performance liquid chromatography and sequenced. Self-peptide mixtures eluted from the mouse H-2Kk class I allele revealed a dominant primary sequence motif, with a carboxyl-terminal residue that appeared to be invariantly valine and a secondary or auxiliary anchor residue at position 2 that could be either glutamate or proline. The majority of naturally processed peptide ligands appeared to be octamers. Although peptides eluted off H-2Kk molecules from tissue derived from a number of different inbred mouse strains also appeared to be octamers, others have reported that isoleucine is the dominant carboxyl-terminal residue. Thus, different cell types displayed distinct differences in naturally processed peptides bound by the same class I alleles. The variation in naturally processed peptides loaded onto the same class I allele most likely reflects the nature of the pool of peptides within the cell available for loading class I molecules.
Veterans Affairs Medical Center, Portland, Oregon, USA. burrowsg@ohsu.edu
G G
GG
Burrows
K
K
Ariail
B
B
Celnik
J E
JE
Gambee
B F
BF
Bebo
H
H
Offner
A A
AA
Vandenbark
D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D017951:Antigen Presentation; D002469:Cell Separation; D005434:Flow Cytometry; D014644:Genetic Variation; D006183:H-2 Antigens / Q000235:genetics*; D006825:Hybridomas / Q000276:immunology*; D051379:Mice; D008969:Molecular Sequence Data; D010455:Peptides / Q000235:genetics / Q000276:immunology*; D051381:Rats; D013601:T-Lymphocytes / Q000276:immunology*
D006183:H-2 Antigens; C024755:H-2K(K) antigen; D010455:Peptides