CAR-T cells and TRUCKs that recognize an EBNA-3C-derived epitope presented on HLA-B*35 control Epstein-Barr virus-associated lymphoproliferation.

Background: Immunosuppressive therapy or T-cell depletion in transplant patients can cause uncontrolled growth of Epstein-Barr virus (EBV)-infected B cells resulting in post-transplant lymphoproliferative disease (PTLD). Current treatment options do not distinguish between healthy and malignant B cells and are thereby often limited by severe side effects in the already immunocompromised patients. To specifically target EBV-infected B cells, we developed a novel peptide-selective chimeric antigen receptor (CAR) based on the monoclonal antibody TÜ165 which recognizes an Epstein-Barr nuclear antigen (EBNA)-3C-derived peptide in HLA-B*35 context in a T-cell receptor (TCR)-like manner.

Conformational Plasticity of HLA-B27 Molecules Correlates Inversely With Efficiency of Negative T Cell Selection.

The development of autoimmune disorders is incompletely understood. Inefficient thymic T cell selection against self-peptides presented by major histocompatibility antigens (HLA in humans) may contribute to the emergence of auto-reactive effector cells, and molecular mimicry between foreign and self-peptides could promote T cell cross-reactivity. A pair of class I subtypes, HLA-B2705 and HLA-B2709, have previously been intensely studied, because they are distinguished from each other only by a single amino acid exchange at the floor of the peptide-binding groove, yet are differentially associated with the autoinflammatory disorder ankylosing spondylitis.

Metal-triggered conformational reorientation of a self-peptide bound to a disease-associated HLA-B*27 subtype.

Conformational changes of major histocompatibility complex (MHC) antigens have the potential to be recognized by T cells and may arise from polymorphic variation of the MHC molecule, the binding of modifying ligands, or both. Here, we investigated whether metal ions could affect allele-dependent structural variation of the two minimally distinct human leukocyte antigen (HLA)-B*27:05 and HLA-B*27:09 subtypes, which exhibit differential association with the rheumatic disease ankylosing spondylitis (AS). We employed NMR spectroscopy and X-ray crystallography coupled with ensemble refinement to study the AS-associated HLA-B*27:05 subtype and the AS-nonassociated HLA-B* 27:09 in complex with the self-peptide pVIPR (RRKWRRWHL).

Increased Conformational Flexibility of HLA-B*27 Subtypes Associated With Ankylosing Spondylitis.

Objective: Dissimilarities in antigen processing and presentation are known to contribute to the differential association of HLA-B*27 subtypes with the inflammatory rheumatic disease ankylosing spondylitis (AS). In support of this notion, previous x-ray crystallographic data showed that peptides can be displayed by almost identical HLA-B*27 molecules in a subtype-dependent manner, allowing cytotoxic T lymphocytes to distinguish between these subtypes. For example, a human self-peptide derived from vasoactive intestinal peptide receptor type 1 (pVIPR; sequence RRKWRRWHL) is displayed in a single conformation by B*27:09 (which is not associated with AS), while B*27:05 (which is associated with AS) presents the peptide in a dual binding mode.

NMR spectroscopy reveals unexpected structural variation at the protein-protein interface in MHC class I molecules.

β2-Microglobulin (β2m) is a small, monomorphic protein non-covalently bound to the heavy chain (HC) in polymorphic major histocompatibility complex (MHC) class I molecules. Given the high evolutionary conservation of structural features of β2m in various MHC molecules as shown by X-ray crystallography, β2m is often considered as a mere scaffolding protein. Using nuclear magnetic resonance (NMR) spectroscopy, we investigate here whether β2m residues at the interface to the HC exhibit changes depending on HC polymorphisms and the peptides bound to the complex in solution.

IR spectroscopic analyses of amyloid fibril formation of β2-microglobulin using a simplified procedure for its in vitro generation at neutral pH.

β2-microglobulin (β2m) is known to be the major component of fibrillar deposits in the joints of patients suffering from dialysis-related amyloidosis. We have developed a simplified procedure to convert monomeric recombinant β2m into amyloid fibrils at physiological pH by a combination of stirring and heating, enabling us to follow conformational changes associated with the assembly by infrared spectroscopy and electron microscopy. Our studies reveal that fibrillogenesis begins with the formation of relatively large aggregates, with secondary structure not significantly altered by the stirring-induced association.

Structural and dynamic features of HLA-B27 subtypes.

Purpose Of Review: The differential association of HLA-B27 subtypes with ankylosing spondylitis provides the rationale for a comparative investigation of these proteins. Results from the last 2 years of research on minimally distinct HLA-B27 subtypes, primarily using biochemical and biophysical techniques, are presented and discussed.

Recent Findings: We summarize evidence that micropolymorphisms within the molecules' peptide-binding groove influence wide-ranging biochemical, biophysical and antigenic properties of HLA-B27 molecules, and suggest that distinct, subtype and peptide-dependent dynamics of peptide - heavy chain - β(2)-microglobulin heterotrimers could be instrumental for an understanding of the initiation of disease processes that are connected with certain HLA-B27 subtypes.

Dynamics of free versus complexed β2-microglobulin and the evolution of interfaces in MHC class I molecules.

In major histocompatibility complex (MHC) class I molecules, monomorphic β(2)-microglobulin (β(2)m) is non-covalently bound to a heavy chain (HC) exhibiting a variable degree of polymorphism. β(2)M can stabilize a wide variety of complexes ranging from classical peptide binding to nonclassical lipid presenting MHC class I molecules as well as to MHC class I-like molecules that do not bind small ligands. Here we aim to assess the dynamics of individual regions in free as well as complexed β(2)m and to understand the evolution of the interfaces between β(2)m and different HC.

Comparative biophysical characterization of chicken β2-microglobulin.

β(2)-microglobulin (β(2)m) is the smallest building block of molecules belonging to the immunoglobulin superfamily. By comparing thermodynamic and structural characteristics of chicken β(2)m with those of other species, we seek to elucidate whether it is possible to pinpoint features that set the avian protein apart from other β(2)m. The thermodynamic assays revealed that chicken β(2)m exhibits a lower melting temperature than human β(2)m, and the H/D exchange behavior observed by infrared spectroscopy indicates a more flexible structure of the former protein.

Endoplasmic reticulum aminopeptidase 1 (ERAP1) exhibits functionally significant interaction with HLA-B27 and relates to subtype specificity in ankylosing spondylitis.

Objectives: The functional interaction of endoplasmic reticulum aminopeptidase 1 (ERAP1) with human leucocyte antigen (HLA)-B*27 could be important in the pathogenesis of ankylosing spondylitis (AS). AS is associated with B*27:04 and B*27:05, but not with B*27:06 and B*27:09. The authors studied the surface expression of peptide-HLA(pHLA)-B27 complexes and HLA class-I free heavy chains (FHCs) on peripheral blood mononuclear cells of patients with AS with different ERAP1 single nucleotide polymorphisms.

Dynamical characterization of two differentially disease associated MHC class I proteins in complex with viral and self-peptides.

Major histocompatibility complex (MHC) class I proteins are expressed on the cell surface where they present foreign and self-peptides to effector cells of the immune system. While an understanding of the structural prerequisites for antigen presentation has already been achieved, insight into subtype- or peptide-dependent dynamical characteristics of a peptide-MHC antigen is so far largely obscure. We approached this problem by employing 400-ns molecular dynamics simulations with two human MHC class I subtypes as model systems: the ankylosing spondylitis-associated HLA-B∗27:05 and the non-ankylosing spondylitis-associated HLA-B∗27:09.

HLA class I-associated diseases with a suspected autoimmune etiology: HLA-B27 subtypes as a model system.

Although most autoimmune diseases are connected to major histocompatibility complex (MHC) class II alleles, a small number of these disorders exhibit a variable degree of association with selected MHC class I genes, like certain human HLA-A and HLA-B alleles. The basis for these associations, however, has so far remained elusive. An understanding might be obtained by comparing functional, biochemical, and biophysical properties of alleles that are minimally distinct from each other, but are nevertheless differentially associated to a given disease, like the HLA-B*27:05 and HLA-B*27:09 antigens, which differ only by a single amino acid residue (Asp116His) that is deeply buried within the binding groove.

Self/nonself perception, reproduction and the extended MHC.

Self/nonself perception governs mate selection in most eukaryotic species. It relies on a number of natural barriers that act before, during and after copulation. These hurdles prevent a costly investment into an embryo with potentially suboptimal genetic and immunological properties and aim at discouraging fertilization when male and female gametes exhibit extensive sharing of alleles.

Influence of inflammation-related changes on conformational characteristics of HLA-B27 subtypes as detected by IR spectroscopy.

Inflammatory processes are accompanied by the post-translational modification of certain arginine residues to yield citrulline, and a pH decrease in the affected tissue, which might influence the protonation of histidine residues within proteins. We employed isotope-edited IR spectroscopy to investigate whether conformational features of two human major histocompatibility antigen class I subtypes, HLA-B*2705 and HLA-B*2709, are affected by these changes. Both differ only in residue 116 (Asp vs.

Loss of recognition by cross-reactive T cells and its relation to a C-terminus-induced conformational reorientation of an HLA-B*2705-bound peptide.

The human major histocompatibility complex class I antigen HLA-B*2705 binds several sequence-related peptides (pVIPR, RRKWRRWHL; pLPM2, RRRWRRLTV; pGR, RRRWHRWRL). Cross-reactivity of cytotoxic T cells (CTL) against these HLA-B*2705:peptide complexes seemed to depend on a particular peptide conformation that is facilitated by the engagement of a crucial residue within the binding groove (Asp116), associated with a noncanonical bulging-in of the middle portion of the bound peptide. We were interested whether a conformational reorientation of the ligand might contribute to the lack of cross-reactivity of these CTL with a peptide derived from voltage-dependent calcium channel α1 subunit (pCAC, SRRWRRWNR), in which the C-terminal peptide residue pArg9 could engage Asp116.

Structure of a classical MHC class I molecule that binds "non-classical" ligands.

Chicken YF1 genes share a close sequence relationship with classical MHC class I loci but map outside of the core MHC region. To obtain insights into their function, we determined the structure of the YF1*7.1/β(2)-microgloblin complex by X-ray crystallography at 1.

Genomic architecture of MHC-linked odorant receptor gene repertoires among 16 vertebrate species.

The recent sequencing and assembly of the genomes of different organisms have shown that almost all vertebrates studied in detail so far have one or more clusters of genes encoding odorant receptors (OR) in close physical linkage to the major histocompatibility complex (MHC). It has been postulated that MHC-linked OR genes could be involved in MHC-influenced mate choice, comprising both pre- as well as post-copulatory mechanisms. We have therefore carried out a systematic comparison of protein sequences of these receptors from the genomes of man, chimpanzee, gorilla, orangutan, rhesus macaque, mouse, rat, dog, cat, cow, pig, horse, elephant, opossum, frog and zebra fish (amounting to a total of 559 protein sequences) in order to identify OR families exhibiting evolutionarily conserved MHC linkage.

Variation and linkage disequilibrium within odorant receptor gene clusters linked to the human major histocompatibility complex.

Odorant receptors (OR) are G-protein-coupled receptors that are predominantly expressed in the membrane of olfactory neurons. Members of the two OR gene clusters on the short arm of human chromosome 6 could be involved in major histocompatibility complex (MHC)-associated behavioral traits, such as olfaction-influenced mate selection and cryptic female choice. In this context, OR gene polymorphisms and haplotypes are likely to play an important role.

Neuronal MHC class I molecules are involved in excitatory synaptic transmission at the hippocampal mossy fiber synapses of marmoset monkeys.

Several recent studies suggested a role for neuronal major histocompatibility complex class I (MHCI) molecules in certain forms of synaptic plasticity in the hippocampus of rodents. Here, we report for the first time on the expression pattern and functional properties of MHCI molecules in the hippocampus of a nonhuman primate, the common marmoset monkey (Callithrix jacchus). We detected a presynaptic, mossy fiber-specific localization of MHCI proteins within the marmoset hippocampus.

HLA-B27 heavy chains distinguished by a micropolymorphism exhibit differential flexibility.

Objective: Although the products of the HLA subtypes B*2705 and B*2709 differ only in residue 116 (Asp versus His) within their peptide-binding grooves, they are differentially associated with inflammatory rheumatic diseases such as ankylosing spondylitis (AS): B*2705 occurs in AS patients, whereas B*2709 is only rarely encountered. The reasons for this distinct association are still unclear but could include subtype-specific conformational and dynamic properties of these antigens. The present study was undertaken to investigate structural and dynamic differences between B*2705 and B*2709 and their possible relationship to subtype-specific disease association.

Implications of structural and thermodynamic studies of HLA-B27 subtypes exhibiting differential association with ankylosing spondylitis.

Structural and thermodynamic properties of HLA-B27 molecules provide the basis for their function within the immune system and are probably also central for the understanding of the pathology of HLA-B27-associated diseases such as ankolysing spondylitis (AS). Several HLA-B27 alleles are AS-associated, whereas some are not, although the protein encoded by the former may differ in only a single amino acid exchange from those specified by the latter. This indicates that subtype-specific polymorphic residues play a key role in determining whether an HLA-B27 subtype is AS-associated or not and open the possibility to correlate structural, thermodynamic and functional characteristics ofa given subtype with the disease association.

Structural basis for T cell alloreactivity among three HLA-B14 and HLA-B27 antigens.

The existence of cytotoxic T cells (CTL) cross-reacting with the human major histocompatibility antigens HLA-B14 and HLA-B27 suggests that their alloreactivity could be due to presentation of shared peptides in similar binding modes by these molecules. We therefore determined the crystal structures of the subtypes HLA-B*1402, HLA-B*2705, and HLA-B*2709 in complex with a proven self-ligand, pCatA (peptide with the sequence IRAAPPPLF derived from cathepsin A (residues 2-10)), and of HLA-B*1402 in complex with a viral peptide, pLMP2 (RRRWRRLTV, derived from latent membrane protein 2 (residues 236-244) of Epstein-Barr virus). Despite the exchange of 18 residues within the binding grooves of HLA-B*1402 and HLA-B*2705 or HLA-B*2709, the pCatA peptide is presented in nearly identical conformations.

Expression, purification and preliminary X-ray crystallographic analysis of the chicken MHC class I molecule YF1*7.1.

YF1*7.1 is an allele of a polymorphic major histocompatibility complex (MHC) class I-like locus within the chicken Y gene complex. With the aim of understanding the possible role of the YF1*7.