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 Phosphorylated Peptides Are Naturally Processed and Presented by Major Histocompatibility Complex Class I Molecules in Vivo

2000 ◽  
Vol 192 (12) ◽  
pp. 1755-1762 ◽  
Author(s):  
Angela L. Zarling ◽  
Scott B. Ficarro ◽  
Forest M. White ◽  
Jeffrey Shabanowitz ◽  
Donald F. Hunt ◽  
...  
Keyword(s):  
T Cells ◽  
Major Histocompatibility Complex ◽  
Mhc Class I ◽  
Class I ◽  
Major Histocompatibility ◽  
Peptide Antigens ◽  
Histocompatibility Complex ◽  
Phosphorylated Peptides ◽  
Mhc Class I Molecules

Posttranslational modification of peptide antigens has been shown to alter the ability of T cells to recognize major histocompatibility complex (MHC) class I–restricted peptides. However, the existence and origin of naturally processed phosphorylated peptides presented by MHC class I molecules have not been explored. By using mass spectrometry, significant numbers of naturally processed phosphorylated peptides were detected in association with several human MHC class I molecules. In addition, CD8+ T cells could be generated that specifically recognized a phosphorylated epitope. Thus, phosphorylated peptides are part of the repertoire of antigens available for recognition by T cells in vivo.

scholarly journals Tumorigenicity conferred to lymphoma mutant by major histocompatibility complex-encoded transporter gene.

1993 ◽  
Vol 177 (1) ◽  
pp. 201-205 ◽  
Author(s):  
L Franksson ◽  
E George ◽  
S Powis ◽  
G Butcher ◽  
J Howard ◽  
...  
Keyword(s):  
Major Histocompatibility Complex ◽  
Nk Cells ◽  
Mhc Class I ◽  
Nk Cell ◽  
Class I ◽  
Antigenic Peptides ◽  
Major Histocompatibility ◽  
Histocompatibility Complex ◽  
Mhc Class I Molecules

Presentation of antigenic peptides by major histocompatibility complex (MHC) class I molecules requires MHC-encoded molecules of the adenosine triphosphate binding cassette (ABC) family. Defects in these proteins represent a potential risk, since they are essential links in the machinery of T cell-mediated surveillance which continuously scrutinizes peptide samples of cellular proteins. Nevertheless, transfection of the mouse lymphoma mutant RMA-S with the rat ABC gene mtp2a (homologue to mouse HAM2 and human RING11), commonly termed TAP-2 genes, led to a marked increase in tumor outgrowth potential in vivo. This occurred despite restored antigen presentation and sensitivity to cytotoxic T lymphocytes, and was found to be due to escape from natural killer (NK) cell-mediated rejection. It has previously been proposed that adequate expression of self-MHC class I is one important mechanism to avoid elimination by NK cells. Our data argue that a defect in the machinery responsible for processing and loading of peptides into MHC class I molecules is sufficient to render cells sensitive to elimination by NK cells. The latter thus appear to function as a surveillance of the peptide surveillance machinery.

scholarly journals Major histocompatibility complex class I molecules mediate association of SV40 with caveolae.

1997 ◽  
Vol 8 (1) ◽  
pp. 47-57 ◽  
Author(s):  
E Stang ◽  
J Kartenbeck ◽  
R G Parton
Keyword(s):  
Major Histocompatibility Complex ◽  
Mhc Class I ◽  
Mammalian Cells ◽  
Simian Virus 40 ◽  
Class I ◽  
Major Histocompatibility ◽  
Surface Binding ◽  
Histocompatibility Complex ◽  
Mhc Class I Molecule ◽  
Mhc Class I Molecules

Simian virus 40 (SV40) has been shown to enter mammalian cells via uncoated plasma membrane invaginations. Viral particles subsequently appear within the endoplasmic reticulum. In the present study, we have examined the surface binding and internalization of SV40 by immunoelectron microscopy. We show that SV40 associates with surface pits which have the characteristics of caveolae and are labeled with antibodies to the caveolar marker protein, caveolin-1. SV40 is believed to use major histocompatibility complex (MHC) class I molecules as cell surface receptors. Using a number of MHC class I-specific monoclonal antibodies, we found that both viral infection and association of virus with caveolae were strongly reduced by preincubation with anti-MHC class I antibodies. Because binding of SV40 to MHC class I molecules may induce clustering, we investigated whether antibody cross-linked class I molecules also redistributed to caveolae. Clusters of MHC class I molecules were indeed shown to be specifically associated with caveolin-labeled surface pits. Taken together, the results suggest that SV40 may make use of MHC class I molecule clustering and the caveolae pathway to enter mammalian cells.

Nonimmune thyroid destruction results from transgenic overexpression of an allogeneic major histocompatibility complex class I protein

1993 ◽  
Vol 13 (3) ◽  
pp. 1554-1564
Author(s):  
A G Frauman ◽  
P Chu ◽  
L C Harrison
Keyword(s):  
Major Histocompatibility Complex ◽  
Beta Cells ◽  
Mhc Class I ◽  
Pancreatic Beta Cells ◽  
Class I ◽  
General Mechanism ◽  
Major Histocompatibility ◽  
Cell Destruction ◽  
Histocompatibility Complex ◽  
Mhc Class I Molecules

The overexpression of major histocompatibility complex (MHC) class I molecules in endocrine epithelial cells is an early feature of autoimmune thyroid disease and insulin-dependent diabetes mellitus, which may reflect a cellular response, e.g., to viruses or toxins. Evidence from a transgenic model in pancreatic beta cells suggests that MHC class I overexpression could play an independent role in endocrine cell destruction. We demonstrate in this study that the transgenic overexpression of an allogeneic MHC class I protein (H-2Kb) linked to the rat thyroglobulin promoter, in H-2Kk mice homozygous for the transgene, leads to thyrocyte atrophy, hypothyroidism, growth retardation, and death. Thyrocyte atrophy occurred in the absence of lymphocytic infiltration. Tolerance to allogeneic class I was revealed by the reduced ability of primed lymphocytes from transgenic mice to lyse H-2Kb target cells in vitro. This nonimmune form of thyrocyte destruction and hypothyroidism recapitulates the beta-cell destruction and diabetes that results from transgenic overexpression of MHC class I molecules in pancreatic beta cells. Thus, we conclude that overexpression of MHC class I molecules may be a general mechanism that directly impairs endocrine epithelial cell viability.

scholarly journals Porcine major histocompatibility complex (MHC) class I molecules and analysis of their peptide-binding specificities

2011 ◽  
Vol 63 (12) ◽  
pp. 821-834 ◽  
Author(s):  
Lasse Eggers Pedersen ◽  
Mikkel Harndahl ◽  
Michael Rasmussen ◽  
Kasper Lamberth ◽  
William T. Golde ◽  
...  
Keyword(s):  
Major Histocompatibility Complex ◽  
Mhc Class I ◽  
Peptide Binding ◽  
Class I ◽  
Major Histocompatibility ◽  
Histocompatibility Complex ◽  
Mhc Class I Molecules

scholarly journals A Common Inhibitory Receptor for Major Histocompatibility Complex Class I Molecules on Human Lymphoid and Myelomonocytic Cells

1997 ◽  
Vol 186 (11) ◽  
pp. 1809-1818 ◽  
Author(s):  
Marco Colonna ◽  
Francisco Navarro ◽  
Teresa Bellón ◽  
Manuel Llano ◽  
Pilar García ◽  
...  
Keyword(s):  
T Cells ◽  
Major Histocompatibility Complex ◽  
B Cells ◽  
Mhc Class I ◽  
Killer Cell ◽  
Class I ◽  
Major Histocompatibility ◽  
Histocompatibility Complex ◽  
Myelomonocytic Cells ◽  
Mhc Class I Molecules

Natural killer (NK) cell–mediated lysis is negatively regulated by killer cell inhibitory receptors specific for major histocompatibility complex (MHC) class I molecules. In this study, we characterize a novel inhibitory MHC class I receptor of the immunoglobulin-superfamily, expressed not only by subsets of NK and T cells, but also by B cells, monocytes, macrophages, and dendritic cells. This receptor, called Ig-like transcript (ILT)2, binds MHC class I molecules and delivers a negative signal that inhibits killing by NK and T cells, as well as Ca2+ mobilization in B cells and myelomonocytic cells triggered through the B cell antigen receptor and human histocompatibility leukocyte antigens (HLA)–DR, respectively. In addition, myelomonocytic cells express receptors homologous to ILT2, which are characterized by extensive polymorphism and might recognize distinct HLA class I molecules. These results suggest that diverse leukocyte lineages have adopted recognition of self–MHC class I molecules as a common strategy to control cellular activation during an immune response.

scholarly journals Highly Pathogenic Simian Immunodeficiency Virus mne Variants That Emerge during the Course of Infection Evolve Enhanced Infectivity and the Ability To Downregulate CD4 but Not Class I Major Histocompatibility Complex Antigens

2002 ◽  
Vol 76 (13) ◽  
pp. 6425-6434 ◽  
Author(s):  
Parul G. Patel ◽  
Monica T. Yu Kimata ◽  
Julia E. Biggins ◽  
Joelle M. Wilson ◽  
Jason T. Kimata
Keyword(s):  
Major Histocompatibility Complex ◽  
Simian Immunodeficiency Virus ◽  
Mhc Class I ◽  
Class I ◽  
Major Histocompatibility ◽  
Highly Pathogenic ◽  
Pathogenic Variants ◽  
Histocompatibility Complex ◽  
Immunodeficiency Virus

ABSTRACT The replicative, cytopathic, and antigenic properties of simian immunodeficiency virus (SIV) variants influence its replication efficiency in vivo. To further define the viral properties and determinants that may be important for high-level replication in vivo and progression to AIDS, we compared a minimally pathogenic SIVmne molecular clone with two highly pathogenic variants cloned from late stages of infection. Both variants had evolved greater infectivity than the parental clone due to mutations in nef. Interestingly, a pol determinant in one of the highly pathogenic variants also contributed to its increased infectivity. Furthermore, because replication in vivo may also be influenced by the ability of a virus to evade the cellular immune response of the host, we examined whether the variants were more capable of downregulating surface expression of class I major histocompatibility complex (MHC). Decreased MHC class I expression was not observed in cells infected with any of the viruses. Furthermore, the Nef proteins of the highly pathogenic variants only slightly reduced surface MHC class I expression in transfected cells, although they efficiently downregulated CD4. Together, these data demonstrate that mutations which can enhance viral infectivity, as well as CD4 downregulation, may be important for efficient replication of SIV in the host. However, Nef-mediated reduction of MHC class I expression does not appear to be critical for the increased in vivo replicative ability of highly pathogenic late variants.

scholarly journals E3/19K from adenovirus 2 is an immunosubversive protein that binds to a structural motif regulating the intracellular transport of major histocompatibility complex class I proteins.

1990 ◽  
Vol 172 (6) ◽  
pp. 1653-1664 ◽  
Author(s):  
W A Jefferies ◽  
H G Burgert
Keyword(s):  
Major Histocompatibility Complex ◽  
Cell Surface ◽  
Mhc Class I ◽  
Intracellular Transport ◽  
Surface Expression ◽  
Class I ◽  
Cell Surface Expression ◽  
Major Histocompatibility ◽  
Histocompatibility Complex ◽  
Mhc Class I Molecules

We have previously expressed in transgenic mice a chimeric H-2Kd/Kk protein called C31, which contains the extracellular alpha 1 domain of Kd, whereas the rest of the molecule is of Kk origin. This molecule functions as a restriction element for alloreactive and influenza A-specific cytotoxic T lymphocytes (CTL) but is only weakly expressed at the cell surface of splenocytes. Here, we show that the low cell surface expression is the result of slow intracellular transport and processing of the C31 protein. A set of hybrid molecules between Kd and Kk were used to localize the regions in major histocompatibility complex (MHC) molecules that are important for their intracellular transport and to further localize the structures responsible for binding to the adenovirus 2 E3/19K protein. This protein appears to be an important mediator of adenovirus persistence. It acts by binding to the immaturely glycosylated forms of MHC class I proteins in the endoplasmic reticulum (ER), preventing their passage to the cell surface and thereby reducing the recognition of infected cells by virus-specific T cells. We find the surprising result that intracellular transport and E3/19K binding are controlled primarily by the first half of the second domain of Kd, thus localizing these phenomena to the five polymorphic residues in this region of the Kd protein. This result implies that the E3/19K protein may act by inhibiting peptide binding or by disrupting the oligomerization of MHC class I molecules required for transport out of the ER. Alternatively, the E3/19K protein may inhibit the function of a positively acting transport molecule necessary for cell surface expression of MHC class I molecules.

scholarly journals Selection and Expansion of CD8α/α1 T Cell Receptor α/β1 Intestinal Intraepithelial Lymphocytes in the Absence of Both Classical Major Histocompatibility Complex Class I and Nonclassical Cd1 Molecules

1999 ◽  
Vol 190 (6) ◽  
pp. 885-890 ◽  
Author(s):  
Se-Ho Park ◽  
Delphine Guy-Grand ◽  
François A. Lemonnier ◽  
Chyung-Ru Wang ◽  
Albert Bendelac ◽  
...  
Keyword(s):  
Major Histocompatibility Complex ◽  
Mhc Class I ◽  
Antigen Processing ◽  
Intraepithelial Lymphocytes ◽  
Class I ◽  
Major Histocompatibility ◽  
Intestinal Intraepithelial Lymphocytes ◽  
Histocompatibility Complex ◽  
Nonclassical Mhc ◽  
Mhc Class I Molecules

Intestinal intraepithelial lymphocytes (IELs) in mice include two main subsets of TCR-α/β1 cells which differ functionally and ontogenically from each other. One expresses the CD8α/α homodimer, whereas the other expresses the CD8α/β heterodimer. Although the presence of all CD8+TCR-α/β1 IELs is dependent on β2-microglobulin molecules, the nature of the major histocompatibility complex (MHC) class I molecules recognized by the CD8α/α and the CD8α/β1 subsets has remained elusive. Using mutant mice lacking the expression of both H2-Kb and H2-Db, we show that the CD8α/β1TCR-α/β1 subset is dependent on K or D molecules, whereas the CD8α/α1TCR-α/β1 subset is independent of classical MHC class I molecules. Furthermore, the CD8α/α1 cells are conserved in mice lacking expression of CD1, a nonclassical MHC class I–like molecule previously proposed to be a potential ligand for IELs. Using transporter associated with antigen processing (TAP)-deficient mice, this cell population can be further separated into a TAP-dependent and a TAP-independent subset, suggesting either the recognition of two nonclassical MHC-like molecules, only one of which is TAP dependent, or the involvement of a single nonclassical MHC-like molecule that is only partially TAP dependent. These findings demonstrate that CD8α/β1TCR-α/β1 IELs are restricted by H-2K and H-2D molecules, whereas the unusual subset of CD8α/α1TCR-α/β1 resident IELs recognize nonclassical MHC class I–like molecules that are distinct from CD1.

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