scholarly journals The class I-b molecule Qa-1 forms heterodimers with H-2Ld and a novel 50-kD glycoprotein encoded centromeric to I-E beta.

1995 ◽  
Vol 181 (2) ◽  
pp. 657-668 ◽  
Author(s):  
P R Wolf ◽  
R G Cook
Keyword(s):  
Cell Surface ◽  
Biochemical Characterization ◽  
Noncovalent Interactions ◽  
Protein Product ◽  
Class I ◽  
Mouse Strains ◽  
Histocompatibility Complex ◽  
Beta 2 Microglobulin

Recent biochemical characterization of the T23-encoded Qa-1 molecule revealed an additional higher molecular mass species of 50 kD coprecipitated with the 48-kD Qa-1 molecule in H-2b and H-2d mouse strains. We now demonstrate that the 50-kD protein coprecipitated with Qa-1 is the class I-a antigen Ld in all H-2Ld-positive mouse strains examined. Furthers analyses of a panel of recombinants revealed that the 50-kD protein coprecipitated with Qa-1 in H-2b haplotype mouse strains is encoded or controlled by a gene centromeric to major histocompatibility complex class II I-E beta. We have designated this gene and corresponding protein product as Qsm, Qa-1 structure modifier. Both Ld and Qsm can interact with Qa-1 to form cell surface-expressed heterodimers in vivo. These Qa-1 heterodimers are not expressed in H-2k haplotype cells. The Qa-1/Ld and Qa-1/Qsm heterodimers are associated by noncovalent interactions and occur only between fully processed proteins. In addition, we show that the Qsm-encoded protein can form heterodimers with Ld as well, and that the Ld molecules participating in these interactions with Qa-1 and Qsm may be devoid of beta 2-microglobulin and/or peptide. These data represent the first demonstration that class I molecules can be expressed as heterodimers (Qa-1/Ld) on the cell surface, and map a gene (Qsm) that may potentially encode a novel class I molecule, or another protein, that associates with both Qa-1 and Ld. These interactions may enable increased levels of Qa-1 to reach the cell surface and may subsequently influence T cell recognition of Qa-1 and/or Ld molecules.

Immunocytochemical localization of thymus-leukemia (TL) antigen on cryosections of thymocytes

1990 ◽  
Vol 48 (3) ◽  
pp. 372-373
Author(s):  
Cheryl Hartfield ◽  
Bruce Loveland ◽  
Alasdair McDowall ◽  
Kirsten Fischer Lindahl
Keyword(s):  
Plasma Membrane ◽  
Major Histocompatibility Complex ◽  
Cell Surface ◽  
Mhc Class I ◽  
Subcellular Fractions ◽  
Class I ◽  
Mouse Strains ◽  
Immunocytochemical Localization ◽  
Isolated Mitochondria ◽  
Histocompatibility Complex

TL antigens are class I molecules of the major histocompatibility complex (MHC). They are present on the surface of cortical thymocytes of certain mouse strains. A recent study finds that a mitochondrially-encoded peptide (MTF) is presented on the cell surface by the MHC class I HMT molecule, which is encoded by a gene closely linked to that encoding TL. These results make it relevant to re-examine earlier reports that TL antigens can be found on mitochondria. In 1978, Jeng et al. demonstrated by classical resin embedding that, in addition to the plasma membrane, isolated mitochondria from TL+ cells could also be labeled with anti-TL alloantiserum and a hemocyanin conjugate. This finding was unexpected, as there was no precedent for the presence of any class I molecules on the surface of mitochondria. However, contamination of subcellular fractions with other cellular constituents is unavoidable, and a control for plasma membrane contamination was not reported by Jeng et al.

scholarly journals Folding and assembly of major histocompatibility complex class I heterodimers in the endoplasmic reticulum of intact cells precedes the binding of peptide.

1993 ◽  
Vol 178 (6) ◽  
pp. 1971-1980 ◽  
Author(s):  
J J Neefjes ◽  
G J Hämmerling ◽  
F Momburg
Keyword(s):  
Major Histocompatibility Complex ◽  
Mhc Class I ◽  
Class I ◽  
In Vivo Studies ◽  
Major Histocompatibility ◽  
Intact Cells ◽  
Histocompatibility Complex ◽  
Beta 2 Microglobulin ◽  
Mhc Class I Molecules

Major histocompatibility complex (MHC) class I molecules are heterotrimers consisting of a polymorphic H chain, beta 2-microglobulin (beta 2m) and peptide. Peptides are thought to associate early during biosynthesis but the order of assembly of class I molecules from their component subunits in intact cells is not settled. We have studied the assembly of MHC class I molecules in intact cells with or without peptide transporters. MHC class I H chain/beta 2m heterodimers can be efficiently recovered only 4 min after translation and are preceded by a folding intermediate. Approximately 2 min after their formation, the class I heterodimers are loaded with peptides resulting in stable class I heterotrimers. In these in vivo studies, no evidence was obtained that peptide binding to the H chain preceded the association with beta 2m. In contrast, nonassembled class I H chains could be recovered immediately after translation, but this pool did not participate in the formation of class I molecules.

scholarly journals Model for the in vivo assembly of nascent Ld class I molecules and for the expression of unfolded Ld molecules at the cell surface.

1993 ◽  
Vol 178 (6) ◽  
pp. 2035-2046 ◽  
Author(s):  
J D Smith ◽  
N B Myers ◽  
J Gorka ◽  
T H Hansen
Keyword(s):  
Cell Surface ◽  
Intracellular Transport ◽  
Time Course ◽  
Significant Proportion ◽  
Surface Expression ◽  
Class I ◽  
Peptide Transport ◽  
Peptide Ligand ◽  
Beta 2 Microglobulin

To characterize the process of class I assembly and maturation, we have studied the Ld molecule of the mouse. Previous studies have shown that a significant proportion of intracellular and surface Ld molecules can be detected in an alternative conformation designated Ldalt1. Nascent Ldalt molecules are non-peptide ligand associated and are weakly associated with beta 2-microglobulin (beta 2m). Unexpectedly, when monoclonal antibodies were added directly to the lysis buffer, significant amounts of Ldalt/beta 2m heterodimer were detected, suggesting that beta 2m association is not necessarily sufficient to induce Ld conformation. By contrast, addition of peptide to cell lysates rapidly induced the folding of beta 2m-associated Ldalt to conformed Ld. Furthermore, the time course and dynamics of this conversion correlated precisely with peptide binding to Ld. The precursor-product relationship of Ldalt and conformed Ld was also visualized in vivo by pulse-chase analysis of BALB/c splenocytes. To investigate the factors that regulate intracellular transport of class I molecules, expression of Ld was studied in the peptide transport-deficient cell line, RMA.S-Ld, and in beta 2m-/- splenocytes. In contrast to wild-type cell lines, both Ldalt and conformed Ld are poorly expressed at the cell surface of RMA.S-Ld and beta 2m-/- splenocytes. Therefore, surface expression of Ldalt is dependent upon the concomitant expression of conformed Ld molecules. To determine whether surface Ldalt molecules can result from melting of conformed Ld molecules, surface Ld molecules were loaded with several different known Ld peptide ligands. Complexes of Ld with different ligands were found to have dramatically disparate surface half-lives. Importantly, the Ld peptide complexes that turned over the most rapidly resulted in the most gain in surface Ldalt, implying that peptide dissociation can induce the accumulation of nonconformed Ld heavy chains at the cell surface.

scholarly journals Expression of H-2Db on the cell surface in the absence of detectable beta 2 microglobulin.

1984 ◽  
Vol 160 (1) ◽  
pp. 317-322 ◽  
Author(s):  
T A Potter ◽  
C Boyer ◽  
A M Verhulst ◽  
P Golstein ◽  
T V Rajan
Keyword(s):  
Cell Surface ◽  
Cytotoxic T Lymphocytes ◽  
Parental Cell ◽  
Class I ◽  
Parental Cell Line ◽  
Complex Class ◽  
Histocompatibility Complex ◽  
Beta 2 ◽  
T Lymphoma ◽  
Beta 2 Microglobulin

In this report we describe a variant of the C57BL/6 T lymphoma EL4 (EL4/Mar) which, in contrast to the parental cell line, expresses neither H-2Kb nor beta2-microglobulin (beta2m) but which does express H-2Db detectable by serology and by alloreactive cytotoxic T lymphocytes (CTL). This observation raises the possibility that H-2Db and perhaps other major histocompatibility complex class I molecules are normally not associated with beta2m on the cell surface. In addition, this report is the first to indicated that alloreactive CTL can interact with a beta2m-free class I antigen.

BIOCHEMICAL CHARACTERIZATION OF SYRIAN HAMSTER CELL SURFACE ALLOANTIGENS. III. HAMSTER ALLOANTISERA IMMUNOPRECIPITATE CLASS II-LIKE, BUT NOT CLASS I-LIKE, MOLECULES

1981 ◽  
Vol 32 (2) ◽  
pp. 106-110 ◽  
Author(s):  
J. WAYNE STREILEIN ◽  
J. THEODORE PHILLIPS ◽  
JOAN STEIN-STREILEIN ◽  
DIANE A. PROIA ◽  
WILLIAM R. DUNCAN
Keyword(s):  
Cell Surface ◽  
Syrian Hamster ◽  
Biochemical Characterization ◽  
Class Ii ◽  
Class I

Ligand Design for Specific MHC Class I Molecules on the Cell Surface

2020 ◽  
Author(s):  
Xizheng Sun ◽  
Reika Tokunaga ◽  
Yoko Nagai ◽  
Ryo Miyahara ◽  
Akihiro Kishimura ◽  
...  
Keyword(s):  
Cell Surface ◽  
Mhc Class I ◽  
Targeted Delivery ◽  
Peptide Ligands ◽  
Class I ◽  
Class I Mhc ◽  
Mhc I ◽  
Histocompatibility Complex ◽  
High Binding Affinity ◽  
Mhc Class I Molecules

<p><a></a><a></a><a>We have validated that ligand peptides designed from antigen peptides could be used for targeting specific major histocompatibility complex class I (MHC-I)</a> molecules on cell surface. To design the ligand peptides, we used reported antigen peptides for each MHC-I molecule with high binding affinity. From the crystal structure of the peptide/MHC-I complexes, we determined a modifiable residue in the antigen peptides and replaced this residue with a lysine with an ε-amine group modified with functional molecules. The designed ligand peptides successfully bound to cells expressing the corresponding MHC-I molecules via exchange of peptides bound to the MHC-I. We demonstrated that the peptide ligands could be used to transport a protein or a liposome to cells expressing the corresponding MHC-I. The present strategy may be useful for targeted delivery to cells overexpressing MHC-I, which have been observed autoimmune diseases.</p>

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