scholarly journals The requirement for proteasome activity class I major histocompatibility complex antigen presentation is dictated by the length of preprocessed antigen.

1996 ◽  
Vol 183 (4) ◽  
pp. 1545-1552 ◽  
Author(s):  
B Yang ◽  
Y S Hahn ◽  
C S Hahn ◽  
T J Braciale

Accumulating evidence has implicated the proteasome in the processing of protein along the major histocompatibility complex (MHC) class I presentation pathway. The availability of potent proteasome inhibitors provides an opportunity to examine the role of proteasome function in antigen presentation by MHC class I molecules to CD8+ cytotoxic T lymphocytes (CTLs). We have investigated the processing and presenting of antigenic epitopes from influenza hemagglutinin in target cells treated with the inhibitor of proteasome activity MG132. In the absence of proteasome activity, the processing and presentation of the full-length hemagglutinin was abolished, suggesting the requirement for proteasome function in the processing and presentation of the hemagglutinin glycoprotein. Epitope-containing translation products as short as 21 amino acids when expressed in target cells required proteasome activity for processing and presentation of the hemagglutin epitope to CTLs. However, when endogenous peptides of 17 amino acids or shorter were expressed in target cells, the processing and presentation of epitopes contained in these peptides were insensitive to the proteasome inhibitor. Our results support the hypothesis that proteasome activity is required for the generation of peptides presented by MHC class I molecules and that the requirement for proteasome activity is dependent on the size of the translation product expressed in the target cell. The implications of these findings are discussed.

1993 ◽  
Vol 178 (2) ◽  
pp. 597-604 ◽  
Author(s):  
A Moretta ◽  
M Vitale ◽  
C Bottino ◽  
A M Orengo ◽  
L Morelli ◽  
...  

Human CD3-16+56+ natural killer (NK) cells have been shown to display a clonally distributed ability to recognize major histocompatibility complex (MHC) class I alleles. Opposite to T lymphocytes, in NK cells, specific recognition of MHC class I molecules appears to induce inhibition of cytolytic activity and, thus, to protect target cells. Since a precise correlation has been established between the expression of the NK-specific GL183 and EB6 surface molecules (belonging to the novel p58 molecular family) and the specificity of NK clones, we analyzed whether p58 molecules could function as receptors for MHC in human NK cells. NK clones displaying the previously defined "specificity 2" and characterized by the GL183+EB6+ phenotype, specifically recognize the Cw3 allele and thus fail to lyse the Fc gamma R+ P815 target cells transfected with Cw3. On the other hand, NK clones displaying "specificity 1" and expressing the GL183-EB6+ phenotype failed to lyse Cw4+ target cells. Addition of the F(ab')2 fragments of either GL183 or EB6 mAb as well as the XA141 mAb of IgM isotype (specific for the EB6 molecules) completely restored the lysis of Cw3-transfected P815 cells by the Cw3-specific NK clones EX2 and EX4. Similarly, both the entire EB6 mAb, its F(ab')2 fragment and the XA141 mAb reconstituted the lysis of C1R, a Fc gamma R- target cell expressing Cw4 as the only serologically detected class I antigen. Thus, it appears that masking of different members of p58 molecules prevents recognition of "protective" MHC class I alleles and thus the delivering of inhibitory signals. Further support to the concept that p58 molecules represent a NK receptor delivering a negative signal was provided by experiments in which the entire anti-p58 mAbs (of IgG isotype) could inhibit the lysis of unprotected Fc gamma R+ P815 target cells, thus mimicking the inhibitory effect of MHC class I molecules.


F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 158 ◽  
Author(s):  
Andy van Hateren ◽  
Alistair Bailey ◽  
Tim Elliott

We have known since the late 1980s that the function of classical major histocompatibility complex (MHC) class I molecules is to bind peptides and display them at the cell surface to cytotoxic T cells. Recognition by these sentinels of the immune system can lead to the destruction of the presenting cell, thus protecting the host from pathogens and cancer. Classical MHC class I molecules (MHC I hereafter) are co-dominantly expressed, polygenic, and exceptionally polymorphic and have significant sequence diversity. Thus, in most species, there are many different MHC I allotypes expressed, each with different peptide-binding specificity, which can have a dramatic effect on disease outcome. Although MHC allotypes vary in their primary sequence, they share common tertiary and quaternary structures. Here, we review the evidence that, despite this commonality, polymorphic amino acid differences between allotypes alter the ability of MHC I molecules to change shape (that is, their conformational plasticity). We discuss how the peptide loading co-factor tapasin might modify this plasticity to augment peptide loading. Lastly, we consider recent findings concerning the functions of the non-classical MHC I molecule HLA-E as well as the tapasin-related protein TAPBPR (transporter associated with antigen presentation binding protein-related), which has been shown to act as a second quality-control stage in MHC I antigen presentation.


1994 ◽  
Vol 179 (5) ◽  
pp. 1613-1623 ◽  
Author(s):  
F Momburg ◽  
J Roelse ◽  
G J Hämmerling ◽  
J J Neefjes

The major histocompatibility complex (MHC)-encoded heterodimeric TAP1/TAP2 transporter (TAP) translocates cytosolic peptides into the lumen of the endoplasmic reticulum (ER), where peptides of 8 to 11 amino acids long associate with MHC class I molecules. We have studied the selectivity of peptide translocation by TAP in streptolysin O-permeabilized cells using glycosylatable, radioiodinated model peptides to detect import into the ER lumen. TAP-dependent translocation of a radiolabeled nonamer peptide was most efficiently inhibited by unlabeled 9- to 11-mer peptides. Peptides between 7 and 40 amino acids long all could inhibit transport, the longer peptides being least effective. Also, peptides shorter than eight amino acids were inefficiently translocated. The use of directly labeled length variants in translocation assays and TLC analysis of the transported material revealed two pathways for translocation: short peptides (7 to 13 amino acids long) were translocated without prior modification. In contrast, transport of longer peptides was not effective. Instead such peptides were clipped by cytosolic peptidases before efficient transport. Our data suggest that TAP preferentially translocates peptides of appropriate length for class I binding. Furthermore, TAP-translocated peptides were rapidly released from the ER unless they were trapped there by being glycosylated or by binding to MHC class I molecules.


1994 ◽  
Vol 180 (2) ◽  
pp. 687-692 ◽  
Author(s):  
B F Daniels ◽  
F M Karlhofer ◽  
W E Seaman ◽  
W M Yokoyama

Target cell expression of major histocompatibility complex (MHC) class I molecules correlates with resistance to lysis by natural killer (NK) cells. Prior functional studies of the murine NK cell surface molecule, Ly-49, suggested its role in downregulating NK cell cytotoxicity by specifically interacting with target cell H-2Dd molecules. In support of this hypothesis, we now demonstrate a physical interaction between H-2Dd and Ly-49 in both qualitative and quantitative cell-cell binding assays employing a stable transfected Chinese hamster ovary (CHO) cell line expressing Ly-49 and MHC class I transfected target cells. Binding occurred only when CHO cells expressed Ly-49 at high levels and targets expressed H-2Dd by transfection. Monoclonal antibody blocking experiments confirmed this interaction. These studies indicate that the specificity of natural killing is influenced by NK cell receptors that engage target cell MHC class I molecules.


1997 ◽  
Vol 8 (1) ◽  
pp. 47-57 ◽  
Author(s):  
E Stang ◽  
J Kartenbeck ◽  
R G Parton

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.


1993 ◽  
Vol 13 (3) ◽  
pp. 1554-1564
Author(s):  
A G Frauman ◽  
P Chu ◽  
L C Harrison

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.


2011 ◽  
Vol 63 (12) ◽  
pp. 821-834 ◽  
Author(s):  
Lasse Eggers Pedersen ◽  
Mikkel Harndahl ◽  
Michael Rasmussen ◽  
Kasper Lamberth ◽  
William T. Golde ◽  
...  

1997 ◽  
Vol 186 (11) ◽  
pp. 1809-1818 ◽  
Author(s):  
Marco Colonna ◽  
Francisco Navarro ◽  
Teresa Bellón ◽  
Manuel Llano ◽  
Pilar García ◽  
...  

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.


1990 ◽  
Vol 172 (6) ◽  
pp. 1653-1664 ◽  
Author(s):  
W A Jefferies ◽  
H G Burgert

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.


1999 ◽  
Vol 190 (6) ◽  
pp. 885-890 ◽  
Author(s):  
Se-Ho Park ◽  
Delphine Guy-Grand ◽  
François A. Lemonnier ◽  
Chyung-Ru Wang ◽  
Albert Bendelac ◽  
...  

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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