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Coexpression of neuronal, glial, and major histocompatibility complex class II antigens on retinoblastoma cells.

This study identifies the presence of major histocompatibility complex class II antigens on retinoblastoma cells. In addition, the modulation of HLA-DR by interferon-gamma as well as the preferential expression of this major histocompatibility complex molecule over HLA-DQ is described. Double labeling experiments revealed that HLA-DR antigen is shared concomitantly with cells of glial and neuronal character. Investigations such as these underscore the possibility that expression of major histocompatibility complex class II antigens may function as immunological components in the host or play a role in the cellular differentiation of these tumor cells.

Antigens↗

Histocompatible unrelated donors for bone marrow transplantation.

Bone marrow transplantation using HLA one haplotype mismatched family donors has been associated with a high incidence of severe graft-versus-host disease, and an increased risk of graft failure. Recently, the use of histocompatible unrelated donors has been investigated when an HLA genotypically identical sibling is not available. Conventional histocompatibility testing of potential unrelated donors does not always predict alloreactivity in vivo. In this review, the preliminary results of histocompatible unrelated transplants are presented and methods of matching unrelated donors discussed.

Bone Marrow Transplantation↗

[Association of antigens of the histocompatibility system in A and B loci in systemic lupus erythematosus].

The typing of histocompatibility HLA-B and A antigens was made in 63 patients with systemic lupus erythematosus (SLE). It was shown that the carriership of some histocompatibility antigens and association of definite antigens, in particular, increases the relative risk of the development of SLE. This was especially applicable to the following gene combinations: HLA-B-8/B12, HLA-B-18/10, HIA-AII/AI/A3 and some others. Definite associations were revealed between carriership of some histocompatibility antigens and development of some manifestations of SLE.

Disease Susceptibility↗

Histocompatibility antigens and insulin-dependent diabetes: a study of 20 Brazilian families.

1. The relationship between histocompatibility antigens (HLA) and insulin-dependent diabetes was examined. The relative frequency of HLA and the relative risk were determined for 20 families containing 82 individuals, 23 of whom had insulin-dependent diabetes. The control group contained 102 individuals. 2. The B8, B13, and B15 antigens had the highest relative frequency in the group of diabetic patients, whereas B5, B7 and B12 were lowest. A high relative frequency of histocompatibility antigens was found not only in the diabetic patients, but also in their parents and siblings. There was a predominance of A2B8, A2B15, and A9B15 haplotypes in the diabetic population. The diabetic siblings had identical haplotypes. 3. These data support previous reports suggesting genetic linkage between susceptibility to diabetes and the histocompatibility antigen system.

Brazil↗

Immunocytochemical localization of class I H-2 histocompatibility antigens of mouse liver.

The subcellular location of class I H-2 histocompatibility antigens was determined for mouse liver using immunocytochemical techniques and correlated with information determined by cell fractionation and analysis in situ. Surface antigens first were localized by standard procedures involving surface labeling with ferritin-labeled antibody. This approach could not be used for internal membranes either in situ or in fractions since the antigens are not expressed at the cytoplasmic surface. For this purpose, thin sections of tissues embedded in Lowicryl were analyzed and quantitated. The in situ analysis confirmed the presence of H-2 antigens on internal membrane compartments as well as on the cell surface and helped rule out the possibility that distributions based on analyses by immunoprecipitation of fractions of internal membranes were influenced greatly by plasma membrane contamination. Quantitation was provided by immunoprecipitation of H-2 antigens from radioiodinated or metabolically labeled isolated and highly purified cell fractions. The findings establish the presence of class I H-2 histocompatibility antigens in endoplasmic reticulum, Golgi apparatus and plasma membrane in the approximate ratios of 1:3:7. No class I H-2 histocompatibility antigens could be detected in mitochondria, salt extracts of isolated membranes or NP-40-insoluble membrane material.

Animals↗

Graft rejection by T cells not restricted by conventional major histocompatibility complex molecules.

The appropriate crosses of mice lacking conventional major histocompatibility complex (MHC) class I or class II molecules generate single- and double-deficient offspring. These were used as donors for skin grafts across major plus minor, or just minor, histocompatibility differences. Surprisingly, in the two circumstances, there was a rapid rejection of grafts lacking both MHC class I and class II molecules. Rejection was mediated by thymically derived CD4+ T cells of the host. We provide evidence that these T cells recognize an unconventional ligand, capable of activating a pre-formed T cell compartment but incapable of positively selecting it. The existence of this unexpected rejection phenomenon should serve to caution those aiming to engineer "universal donor" cells by simply abrogating expression of MHC class I and class II molecules.

Animals↗

TNF2, a polymorphism of the tumour necrosis-alpha gene promoter, is a component of the celiac disease major histocompatibility complex haplotype.

Celiac disease (CD) is an immune disease triggered by the cereal antigen gliadin, resulting in villous atrophy in the small intestine. Susceptibility to the development of CD is strongly influenced by genes in the major histocompatibility complex, in particular alleles of the DQ genes in the class II region. However recent evidence has suggested that the major histocompatibility complex (MHC) class III region may be linked to celiac disease independently of the class II region. Among the genes located in this area is TNF-alpha, which encodes the cytokine tumor necrosis factor-alpha which has a broad range of pro-inflammatory, immunomodulatory and catabolic activities. Therefore, aberrant expression of TNF-alpha could be important in the pathogenesis of MHC-associated immune disorders. A TNF-alpha variant with a polymorphism in its promoter region has been described and designated TNF2. TNF2 has been associated with a variety of MHC-linked diseases, including systemic lupus erythematosus, dermatitis herpetiformis and insulin-dependent diabetes mellitus (IDDM), as well as parasitic infections. TNF2 has previously been shown to be associated with the MHC haplotype HLA A1-B8-DR3-DQ2, which confers susceptibility to CD. We have analyzed the distribution of TNF2 alleles in a group of celiac patients (n = 52) compared to controls (n = 52) in an effort to evaluate its role, if any, in susceptibility to the condition. TNF2 has a frequency of 0.5000 (SE +/- 0.0490) in CD, compared to 0.1635 (+/- 0.0362) in a control sample (p < 10(-6)). Of 52 patients, 44 carried one or more TNF2 alleles. Analysis indicates that the distribution of TNF2 is best explained by assuming 100% allelic association between it and HLA-DQB1*0201 (frequency = 0.7791 +/- 0.0447). However, the number of TNF2 heterozygotes significantly exceeds expectations and measurements of linkage disequilibrium confirm that allelic associations spanning the DQ and TNF regions are strongly maintained in CD. Taken together, these results indicate that TNF2 may have a role in the pathogenesis of CD; however, since it is not an independent association, the possibility that TNF2 constitutes a passive component of the CD haplotype cannot be excluded.

Alleles↗

The T/B cell interaction involved in induction of the mouse IgG2ab suppression is restricted by major histocompatibility complex class I, but not class II molecules.

To determine the major histocompatibility complex (MHC) restriction of the T/ B cell interaction involved in a negative regulation of Ig production, we used mouse model of T cell-induced IgG2ab suppression in vivo. Normal or specifically triggered T splenocytes from mice of the Igha haplotype, when neonatally transferred into histocompatible Igha/b heterozygotes, are able to induce a specific and total suppression of the IgG2ab allotype. Nevertheless, only transfer of IgG2ab-primed Igha T splenocytes induces this suppression in Ighb/b homozygous congenic mice in which the whole IgG2a isotype production is inhibited. This suppression is chronically maintained by CD8+ T cells, but can be experimentally reversed. We have established that the suppression induction required a CD4+CD8+ T cell cooperation and operated via the recognition by the involved TCR of C gamma 2ab-derived peptides presented by the target B cells in an MHC haplotype-restricted manner. Here, by using Ighb mice genetically deficient for MHC class I (beta 2-microglobulin%, or beta 2m%) or class II (I-A beta%) molecules, we demonstrate functionally that the suppression induction implicates an MHC class I-, but not class II-restricted interaction. Indeed, the anti-IgG2ab T cells transferred into Ighb H-2b I-A beta% mice carry out the suppression process normally, while in Ighb H-2b beta 2m% recipients, their suppression induction capacity is significantly inhibited. Moreover, the C gamma 2ab 103-118 peptide, identified as the sole C gamma 2ab-derived peptide able to amplify the anti-IgG2ab T cell reactivity in Igha H-2b mice, is also able to stabilize the H-2Db, but not the H-2Kb class I molecules at the surface of RMA-S (TAP2-, H-2b) cells. These results indicate that, despite the CD4+/CD8+ T cell cooperation during the induction phase of suppression only MHC class I molecule expression is required at the surface of IgG2ab+ B cells for suppression establishment.

Adoptive Transfer↗

Importance of minor histocompatibility antigens in the development of allograft arteriosclerosis.

Although acute rejection has been mostly ameliorated with the use of powerful immunosuppressive drugs, kidney and heart transplants continue to succumb to a more chronic response characterized by intimal lesions in the graft vasculature. This late-stage response is referred to as allograft arteriosclerosis. Allorecognition is clearly involved in the initiation of this response but the relative importance of major histocompatibility (MHC) and minor histocompatibility (mH) antigens remains unclear. By taking advantage of the B10 congenic set of mice and our newly described mouse aortic interposition graft model we have been able to assess the contribution of these antigens to the development of the concentric intimal lesions characteristic of allograft arteriosclerosis. We performed transplants between syngeneic animals, animals which were disparate at both MHC and multiple mH, animals which were disparate at MHC only, and animals which were disparate at multiple mH antigens only. H-Y antigen variation was controlled for by performing all transplants between female mice. In all cases the recipients were C57BL/10 (H-2b) mice. Both cellular infiltration into the intima and resulting intimal thickness were measured at 2, 4, 8, and 13 weeks posttransplant. At all time points, the grafts from MHC disparate only donors showed less severe intimal lesions than the grafts from fully disparate or mH disparate donors. This difference reached statistical significance at 4 and 13 weeks. This suggests that mH antigens are as immunogenic as MHC antigens with respect to the generation of allograft arteriosclerosis. These findings are not unique to vascular grafts and may relate to the importance of indirect antigen presentation in the development of chronic rejection.

Animals↗

Analysis of the structure of naturally processed peptides bound by class I and class II major histocompatibility complex molecules.

Antigen-specific T-cell responses require antigenic peptides presented on the cell surface by the major histocompatibility complex (MHC) molecules. The structural characteristics of these peptides are being defined. It is now known that the majority of peptides that associate with MHC Class I are 8-10 residues long, with allotype-specific binding motifs containing up to three anchor positions. This is consistent with the presence of six pockets and the close-ended structure of the MHC Class I peptide binding groove. In contrast to peptides associated with MHC Class I, those associated with MHC Class II are 10-34 residues in length and are commonly presented in nested sets with extensions or truncations at the N- or C-terminal ends. Binding motifs for MHC Class II appear to contain up to four anchor positions, with more loosely defined amino acid preferences. The expression of histocompatibility proteins in cells that do not load peptides but fold them correctly has permitted the X-ray analysis of the three-dimensional structure of Class I and Class II complexes with single defined peptides. The differences in length between the Class I and Class II sequences can be ascribed to small structural differences between the two binding sites and the positioning of key residues, that make hydrogen bonds to the bound peptides. Recent advances in mass spectrometry are making possible the analysis and sequencing of subpicomolar quantities of MHC-bound peptides and the estimation of the size of the total population of peptides. The sequence information derived from this technique, in conjunction with X-ray crystallographic analysis of MHC complexes involving single, defined peptides, may provide a new approach towards the development of useful reagents for therapeutic intervention.

Alleles↗

Major histocompatibility antigens and lymphocyte subsets during experimental allergic neuritis in the Lewis rat.

Major histocompatibility antigens were identified in frozen sections of normal Lewis rat peripheral nerve tissue with monoclonal antibodies and an avidin-biotin-peroxidase complex system. Class I antigen is normally required for cytotoxic/suppressor T lymphocyte function and class II antigen for activation of helper T lymphocytes. In the sciatic nerves class I antigen was expressed diffusely by most endoneurial and perineurial cells but class II antigen only by a minority. In the cauda equina class I antigen was expressed by all arachnoid and some endoneurial cells, while class II antigen was expressed by a smaller proportion of arachnoid cells in the endoneurium of spinal roots and interstitial cells surrounding dorsal root ganglion neurons. The endothelium of endoneurial, perineurial and meningeal vessels uniformly expressed class I but not class II antigen. Experimental allergic neuritis was induced in Lewis rats by immunisation with bovine intradural root myelin. Early lesions consisted of multifocal infiltration of the nerve roots by cells expressing leucocyte common antigen. Surrounding endoneurial cells showed markedly increased expression of major histocompatibility antigens. In inflammatory lesions about 10% of the cells were stained with pan T cell antibodies. T lymphocyte subsets were identified with antibody W3/25 for helper cells and MRC OX-8 for cytotoxic/suppressor cells. The W3/25 positive cells were usually slightly in excess of OX-8 positive cells and their relative proportions did not alter during the disease. The presence of class I antigen on normal endothelium and its increased expression on endoneurial cells in the early phase of inflammation suggest an important role for class I restricted lymphocytes in the pathogenesis of the early stages of experimental allergic neuritis.

Animals↗

Major histocompatibility complex of the mole-rat. I. Serological and biochemical analysis.

The mole-rat, Spalax ehrenbergi, is a complex subterranean rodent species whose habitat is restricted largely to the Middle East and North Africa. We typed over 50 mole-rats with mouse monoclonal and polyclonal antibodies specific for class I and class II major histocompatibility complex (Mhc) molecules. Some of these antibodies were produced against mouse Mhc molecules, others against Mhc molecules of other species. About 25% of the antibodies reacted with mole-rat lymphocytes in the cytotoxic test. Some of the serologically positive antibodies precipitated from a glycoprotein pool of mole-rat spleen cell molecules that corresponded in size with class I and class II molecules of other species. We conclude, therefore, that mole-rats, like other mammals, possess the Mhc which consists of class I and class II loci. We call this Mhc Spalax major histocompatibility (Smh) complex. The occurrence of a large number of different serotypes among the tested animals suggests that Smh loci are polymorphic. This Mhc polymorphism of the mole-rat contrasts with the monomorphism or oligomorphism of the Syrian hamster, a rodent with a similar ecology. Thus far no qualitative correlation could be found between Smh polymorphism and chromosome variation described in this superspecies.

Animals↗

Chromosomal localization of the major histocompatibility complex of the horse (ELA) by in situ hybridization.

The first gene assignment to a horse chromosome is reported for equine leucocyte antigen (ELA), the major histocompatibility complex of the horse. A cloned DNA sequence derived from a class I gene of the porcine major histocompatibility complex was used as a probe for an in situ hybridization experiment. We present the regional localization of ELA, using this sequence, to equine chromosome 20q14-q22.

Animals↗

Complexity at the mouse minor histocompatibility locus H-4.

The fine immunogenetics of the chromosome 7 mouse minor histocompatibility (H) locus H-4 was investigated. Both class I major histocompatibility complex (MHC)-restricted cytotoxic T lymphocytes (CTL) and class II MHC-restricted "helper" T cells (TH) specifically reactive with H-4 antigens were isolated as clones and were used as genetic probes for classical backcross segregation analysis. Results of a four point cross indicated that the H-4 locus was actually comprised of two genes, that have been designated H-46 and H-47. The former encodes antigens recognized by the TH and the latter encodes antigens recognized by the CTL. Moreover, these two genes could be separated from the gene pink-eyed dilution (p) which was found to be "sandwiched" between them. The functional significance of a minor H congenic strain differing by both TH-defined H-46 and CTL-defined H-47 was addressed using F1 complementation tests. Such studies indicated that immune responses against H-46 antigens was required for generation of H-47-specific CTL. Altogether, these results suggest selective presentation of different minor H gene products by class I or class II MHC proteins and that the minor H "locus" H-4 may have necessarily included both TH and CTL-defined genes because of requisite TH-CTL collaboration.

Animals↗

Interaction of H-2Db with mutant histocompatibility gene H (KH-11) in the mouse.

The detectable presence of H (KH-11)b, a mutant non-H-2 histocompatibility gene, was previously shown to depend upon the simultaneous presence, in the skin-graft donor, of both the mutant gene and the H-2b haplotype. The experiments reported here demonstrate that H-2Db is the essential element of H-2b for this interaction. Of two H-2Db histocompatibility mutations, H-2bm13 can replace H-2Db in this interaction, but H-2bm14 cannot.

Animals↗

Allelic variation in the DR subregion of the canine major histocompatibility complex.

Allelic variation in the DR subregion of the canine major histocompatibility complex (DLA) has been analyzed by nucleic acid sequencing of cDNA clones of DRB genes amplified in vitro by the reverse transcriptase-polymerase chain reaction (RT-PCR). Sequence analysis of a panel of 19 homozygous typing cell dogs representing 12 different DLA-D types (defined by mixed leucocyte reaction) demonstrated the presence of one expressed DRB locus with at least nine distinct alleles in the dog. Unique DLA-DRB alleles were found in the DLA-D types Dw1, Dw3, Dw4, Dw8 (workshop assignments) and D4, D6, D7, D8, and D9 (Seattle assignments). In contrast, the DRB genes of the remaining three DLA-D types (D1, D10, and D16) were identical to those of Dw3/Dw4 (for D1), Dw8 (for D10), and D6 (for D16). The nucleotide sequences of all nine DLA-DRB alleles were typical of functional major histocompatibility complex (MHC) class II beta chains and contained three allelic hypervariable regions (HVRs) in the beta 1 domain at positions 8-16, 26-39, and 57-74. At each variable residue, two to five amino acid substitutions were found. The most polymorphic residues were located at positions 37 (with five amino acid substitutions), 11, 13, 28, and 71 (each with four substitutions). The DLA-DRB alleles had 96%-99% overall nucleotide sequence similarity and 93%-99% amino acid sequence similarity with each other. Cluster analysis of the nucleotide and predicted amino acid sequences subdivided the DLA-DRB alleles into three major allelic groups which may represent the canine counterparts of the supertypic groups described in man.

Alleles↗

Vascular transplant rejection of rat renal allografts across strong histocompatibility barriers.

Sixty-one rat renal allografts were studied by light microscopy and in 18 cases also by immunohistology. Donor and recipient differ at a major histocompatibility locus in the one group (n = 37), and by an additional weak histocompatibility antigen in the other (n = 24). The mean survival time is 10.4 days and 8.3 days, respectively. A semiquantitative grading of the histologic findings shows that in both groups the rejection is predominantly manifested by lesions of extraglomerular and glomerular vessels, whereas mononuclear cell infiltration appears to be of less significance. The essential findings are necrosis of arteries and arterioles, necrosis of glomerular cells with mesangiolysis, and focal tubular necroses. This morphologic rejection type is interpreted as the result of a mixed humoral and cellular immune response, although the constant participation of circulating antibodies in the vascular damage could not be established. Since the tubular necroses correlate well with the degree of vascular alterations, but not with the mononuclear cell infiltration it would seem reasonable to conclude that these necroses are secondary to ischemia produced by vascular lesions. Finally, there is no significant difference in the degree of rejection between the two donor/recipient groups, and, therefore, there is no morphologic evidence for an increase of the rejection process by additional weak histoincompatibility in the examined strain combinations.

Animals↗

Differential sensitivity of head and neck cancers to non-major histocompatibility-restricted killer cell activity.

Cell lines derived from squamous cell carcinoma of the upper aerodigestive tract (head and neck cancer) were phenotypically characterized with regard to differential sensitivity to nonmajor histocompatibility restricted (non-MHCr) killer cell activity. Requirements for detectable lysis of the cell lines in a standard chromium release assay included either isolation of fresh enriched Leu 19+ large granular lymphocytes (both Leu 19+CD3+ and Leu 19+CD3- populations) or interleukin-2 (IL-2) stimulation of peripheral blood lymphocytes (PBL). In neither circumstance could lytic activity be identified among Leu 19- populations. With PBL IL-2 stimulation significant differential sensitivity to lysis expressed by the head and neck cancer cell lines (P less than 0.001 by analysis of variance) was identified and maintained regardless of PBL source, i.e., PBL from healthy controls and three differing populations of head and neck cancer patients categorized by disease status and treatment. One factor associated with a cell line's increased sensitivity was degree of tumor differentiation, poorly differentiated tumors (as defined by intermediate filament cytochemical staining [decreased keratin and increased vimentin]) being more sensitive. Furthermore, as tumor cell lytic sensitivity increased, major histocompatibility complex (MHC)-class I antigen expression diminished concurrently. In 1 of 4 cell lines tested, however, pretreatment of tumor cells with interferon-gamma induced diminished lytic sensitivity independent of changes in MHC-class I expression, indicating factors not related to MHC-class I expression are likewise relevant. In previous studies we defined the in vivo prognostic significance of non-MHCr killer cell cytotoxicity activity against K562 targets, diminished activity being principally predictive of metastatic disease development in persons with poorly differentiated head and neck cancers. This report extends these observations by demonstrating in vitro that poorly differentiated head and neck cancer target cells are highly sensitive to changes in lytic function expressed by Leu 19+ non-MHCr effector cells.

Carcinoma, Squamous Cell↗