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PubMed1995

MHC class I and class II determinants and some adhesion molecules are engaged in the regulation of nitric oxide production in vitro by human monocytes stimulated with colon carcinoma cells.

Surface molecules that are involved in tumor-monocyte interactions were studied. The in vitro system in which human blood monocytes are stimulated with human colon carcinoma cells for nitric oxide (NO) production was used. Monoclonal antibodies (mAbs) against various adhesion molecules (LFA-1, ICAM-1, VNR) were unable to block NO production in coculture of monocytes with carcinoma cells. However, anti-CD44, -LFA-3, and -VLA beta 1 chain mAbs effectively blocked NO production. Also mAbs against MHC class I and HLA-DR molecules inhibited, in a dose-dependent manner, No release. It was concluded that some adhesion molecules and MHC class I and/or class II determinants of monocytes may be involved in tumor-monocyte interactions leading to signal transduction for NO production.

Antibodies, Monoclonal↗

PubMed2000

BTL-II: a polymorphic locus with homology to the butyrophilin gene family, located at the border of the major histocompatibility complex class II and class III regions in human and mouse.

Comparison of human and mouse genomic sequence at the border of the major histocompatibility complex (MHC) class II and class III regions revealed a locus encoding six exons with homology to the butyrophilin gene family and the location of a previously described gene, testis-specific basic protein (TSBP). We named the new locus BTL-II, for butyrophilin-like MHC class II associated. The six discernable exons of the BTL-II locus encode a small hydrophobic amino acid sequence (which may be a signal peptide), two immunoglobulin domains, a small 7-amino acid, heptad repeat-like exon, and a further two immunoglobulin domains. In mouse, an additional butyrophilin-like gene (NG10) is situated adjacent to BTL-II. Expression studies of the BTL-II locus in mouse showed that it is expressed in a range of gut tissues. We demonstrate that like many other genes from the MHC, BTL-II is polymorphic in a selection of diverse HLA haplotypes. In the light of the newly discovered locus, we revisit and discuss the possible origin of the butyrophilin gene family.

Amino Acid Sequence↗

PubMed1980

Differential diagnosis of class II malocclusions. Part 1. Facial types associated with class II malocclusions.

By means of computer-based statistical methods, several types of Class II malocclusion have been discovered with defining horizontal and vertical characteristics. Of the six horizontal types, four are severe syndromes, one is a loose, ill-defined grouping of cases with mild skeletal features, and one has only the dental features of Class II. Five vertical types associates with Class II were also revealed, although each vertical is not associated with all horizontal types. A simplified simulation of the computerized procedures has been developed for routine use in clinical practice.

Child↗

PubMed1990

Nucleotide sequence of the HLA-A26 class I gene: identification of specific residues and molecular mapping of public HLA class I epitopes.

A cosmid clone bearing an HLA class I gene has been isolated from a human genomic library by hybridization to a class I-specific probe. This clone encodes the HLA-A26 molecule characterized by immunologic reagents on murine transfected L cells. Nucleotide sequencing of the A26 allele has been performed, and the deduced amino acid sequence was compared with previously published HLA class I sequences. Amino acid sequence homologies between HLA-A26 molecules and members of the HLA-AW19 cross-reactive group were observed and allowed us to demonstrate that residue Q144 is the only critical residue involved in the binding of the 4E monoclonal antibody defining an epitope common to all HLA-B, -C, and -Aw19 alleles. This study also permitted designation of a V residue at position 189 in the third domain as possibly involved in the binding of the B1-23-2 monoclonal antibody. Furthermore, we located clusters of variability in reference to the three-dimensional structure of the HLA-A molecules, i.e., the ninth residue of the first beta-strand domain, the upper surface of the first helical region, and both beta and alpha structures of the alpha 2 domain.

Amino Acid Sequence↗

PubMed1992

HLA polymorphism in a Mataco South American Indian tribe: serology of class I and II antigens. Molecular analysis of class II polymorphic variants.

In the present study, HLA-A, B, C, DR, DQ, and DP loci were analyzed in a group of Mataco Amerindians of Argentina. Using reagents from the 11th International Histocompatibility Workshop (11th IHW), class I specifities such as Bw70, Bw75, and Bw48 were found in this population, other than the HLA determinants commonly described in South American Indians. The class II antigens found were DR4, DRw14, and DRw8 at the DR locus, and DQw4 and DQw7 at the DQ locus. The analysis of DRB1-DR4 related alleles, performed by PCR amplification and oligonucleotide probe hybridization, showed the presence of DRB1*0403, *0404, *0405, and *0411 in individuals from this ethnic group. By the analysis of DRB1-DRw14 related alleles, two variants were found: DRB1*1402 and DRB1*1406, the latter provisionally called DRB1 14.6 in 11th IHW. The DRw8-related allele present was DRB1*0802. The analysis of DRB3 gene revealed only the presence of DRB3*0101 allele in DRw14 individuals. DPB1 locus was also analyzed in unrelated individuals of the same population. Only five DPB1 alleles were found: DPB1*0201, *0301, *0402, *0501, and *1301 over the 19 previously described in the literature. These findings emphasize the restricted HLA class I and II variation observed in this ethnic group as it has been previously shown in other American groups. Some particular haplotypes in this Mataco tribe are described in this work.

Alleles↗

PubMed1991

Lack of class variation in health in adolescence: an artefact of an occupational measure of social class?

We have previously shown, using a wide range of health measures, that there is little evidence of consistent class gradients in health in adolescence. This paper examines the possibility that those findings were an artefact of the measure of class used. Seven indicators of health, development and functioning are investigated using six different occupationally-based and five non-occupationally based measures of socio-economic status. The results do not alter the conclusion of the earlier paper, namely that in adolescence class gradients are not consistently apparent in most indicators of health.

Adolescent↗

PubMed1995

Activation of class II MHC genes requires both the X box region and the class II transactivator (CIITA).

CIITA, a gene that can complement a transcriptional mutation of the major histocompatibility complex (MHC) class II genes, was tested for its ability to function as a coactivator, CIITA cDNA clones isolated showed alternative RNA splicing, but only one splice site combination was able to restore class II MHC gene expression. DNA-mediated transfection experiments showed that CIITA directs its activity through the X box element; the presence of CIITA leads to the formation of a higher order complex at the X box region; and CIITA contains a potent activation domain. These findings support the hypothesis that CIITA directly interacts with the MHC class II-specific transcription factors and is required for expression.

Alternative Splicing↗

PubMed1995

The cytoplasmic and transmembrane domains of MHC class II beta chains deliver distinct signals required for MHC class II-mediated B cell activation.

Class II-mediated signals play potential roles in B cell activation and antigen presentation. The regions of the class II molecule participating in B cell signaling are incompletely defined. Our prior analysis of structural requirements of the cytoplasmic domain of A beta revealed that only the eight membrane-proximal residues are required for signaling. Here, we report that the sequence and position of two of these are critical, and present direct evidence that the A beta transmembrane domain is also involved in signaling, via a pathway distinct from the cytoplasmic domain. These results demonstrate that specific regions in both the cytoplasmic and transmembrane domains of the class II molecule have distinct signaling functions.

Amino Acid Sequence↗

PubMed2005

Reconstitution of expression of H-2K region-encoded murine MHC class I glycoproteins in MHC class I-deficient B16BL6 melanoma cells affects the expression and function of antigen-processing machinery.

We have recently reported that reconstitution of expression of major histocompatibility complex (MHC) class I glycoproteins in MHC-deficient and highly metastatic B16BL6 melanoma cells attenuates their malignant capacities by modulation of compartmentalization and functions of cell membrane receptors for growth factors [Assa-Kunik E, et al. J Immunol 2003;171:2945-52]. Our present study provides evidence that re-expression of an H-2K MHC class I-encoding gene in these cells also augments the expression of the Tap-2 peptide transporter and the inducible proteasome subunits, i.e. Lmp-2, Lmp-7 and Lmp-10. Up-regulation of inducible proteasome subunits was also followed by a significant changed in the proteolytic activity of the proteasome complex. We suggest that, in addition to providing a framework for proper presentation of antigenic peptides, MHC class I glycoproteins may regulate the immune response by modulating the expression and function of other genes, whose products are essential for proper antigen processing and presentation.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2004

MHC class I manipulation on cell surfaces by gene transfer of anti-MHC class I intrabodies--a tool for decreased immunogenicity of allogeneic tissue and cell transplants.

Intrabodies (IB) are suitable tools to down-regulate the expression of cell surface molecules in general. In this work, the appearance of major histocompatibility (MHC) class I molecules on the cell surface could be prevented by the expression of intracellularly localized anti-MHC class I antibodies. The expression of MHC antigens presenting intracellularly synthetised peptides on the cell surface is the predominant reason for immunologic detection and rejection of allogeneic cell and tissue transplants. Allogeneic keratinocyte sheets might be a suitable tool for skin grafting. Within this study primary rat keratinocytes have been transfected with anti-MHC I-IB. Strong IB-expressing cells showed a MHC I "knockout" phenotype. The cells did not exhibit any significant alterations compared to non-transfected cells: the cell growth and the expression of other surface molecules were unaltered. Merely an enhanced intracellular accumulation of MHC I molecules could be detected. Notably, IB-expressing keratinocytes displayed a reduced susceptibility to allogeneic cytotoxic T cells in vitro compared to unmodified cells with a normal level of MHC I surface expression. These MHC I-deficient keratinocytes might be utilized in tissue-engineered allogeneic non-immunogeneic skin transplants. The principle of MHC class I manipulation in general can be used for other allogeneic cell and tissue-engineered transplants as well.

Animals↗

PubMed2002

Distribution of class I and class III MHC antigens in the Tarasco Amerindians.

Class I and class III major histocompatibility complex (MHC) antigen frequencies were analyzed in 130 haplotypes from 33 families belonging to a group of Amerindians culturally and linguistically isolated for more than 12 centuries in Mexico: the Tarascos. The most frequent antigens in this ethnic group of the HLA-A locus are: A2 (gf 0.353), A24 (gf = 0.223), A31 (gf = 0.184), and A28 (gf = 0.161); and the most frequent of the HLA-B locus are: B35 (gf = 0.230), B39 (gf = 0.192), B15 (gf = 0.146), and B5 (gf = 0.123). On the other hand, class III antigens demonstrated relatively high frequencies of the SC31 (frequency = 0.561), SC01 (frequency = 0.076), and SC42 (frequency = 0.069) complotypes. Also important was the relatively high frequency of the HLA-B27 antigen (gf 0.061) and the SC33 complotype (frequency = 0.046), which are either absent or found infrequently in other Amerindian groups. Analysis of MHC haplotypes revealed that four of them have relatively high frequencies, these were the following: [B39;SC31] (11.6%), [B35;SC31] (11.6%), [B15;SC31] (8.0%), and [B5;SC31] (5.8%). Other MHC haplotypes had frequencies lower than 5.0%. The decreased frequency of BF alleles other than BF*S and the presence of the SC33 and SC32 complotypes suggest long time preservation from genetic admixture. This information withstands the basis for population genetic analysis and disease association studies in Mexican mestizos.

Complement C2↗

PubMed2003

Long-term stability of skeletal Class III patients treated with splints, Class III elastics, and chincup.

Long-term results from orthopedic management of skeletal Class III malocclusions are sparse. The purpose of this study was to evaluate the stability of results after facial growth and treatment with splints, Class III elastics, and chincup (SEC III) and to investigate the main determinants of relapse. Data from pretreatment, posttreatment, and long-term (at least 3 years after retention) serial cephalograms of 52 patients who received SEC III treatment were studied: only those with long-term data when growth had ceased (women over 18 and men over 21 years of age) were selected. At the end of the follow-up period (an average of 9 years), only 6 of the 52 patients had clinical relapse (overjet <or= 0). Low Wits appraisal, ANB angle, and overbite, and high SNB angle were the best predictors of relapse at the end of the treatment. Significantly greater decreases of the Wits appraisal and increases of ramus length during the follow-up were further associated with relapse. SEC III is a reliable treatment for skeletal Class III malocclusions. Long-term stability can be enhanced by a deeper overbite and the best possible skeletal correction. The results suggest that the correction occurs with no mandibular rotation but might be better with forward rotation.

Adolescent↗

PubMed1990

Transgenic mice expressing a soluble foreign H-2 class I antigen are tolerant to allogeneic fragments presented by self class I but not to the whole membrane-bound alloantigen.

The properties of transmembrane and soluble transplantation antigens were compared with respect to the induction of tolerance and the selection of the T-cell repertoire. For this purpose, transgenic (H-2b x H-2d)F1 mice were constructed that carry integrated copies of a modified H-2Kk gene resulting in the secretion from various cell types including thymocytes of soluble H-2Kk molecules. Despite the presence of H-2Kk antigen, these mice were still able to generate an H-2Kk-specific T-cell response. This response was comparable to that produced by normal littermates when stimulated with cells expressing membrane H-2Kk in a mixed lymphocyte reaction. In contrast, only transgenic mice failed to generate a cytolytic T-cell response to soluble H-2Kk antigen expressed by recombinant vaccinia virus and presented by the H-2Db molecule. These data imply the presence of two populations of alloreactive cytolytic T cells. A small fraction of T cells recognizes alloantigen as antigenic peptide(s) presented by other major histocompatibility complex class I molecules and tolerance can be induced in this population by soluble alloantigen. The majority of T cells, however, require the whole cell membrane-expressed class I molecule for recognition. This population is not affected by tolerance induction to the soluble major histocompatibility complex class I molecule.

Animals↗

PubMed2002

Identification of specific glycoforms of major histocompatibility complex class I heavy chains suggests that class I peptide loading is an adaptation of the quality control pathway involving calreticulin and ERp57.

Glycosylation analysis was used to probe the sequence of events accompanying the binding of antigenic peptides to the major histocompatibility complex class I heavy chains. Free heavy chains were isolated from the beta(2)-microglobulin-negative cell line Daudi and from the B-lymphoblastoid cell line Raji. Heavy chains were also isolated from Raji cells in multimolecular complexes (peptide loading complexes) containing the transporter associated with antigen processing, tapasin and ERp57 with and without the lectin-like folding chaperone, calreticulin. Calreticulin is a soluble protein that recognizes primarily the terminal glucose of Glc(1)Man(7-9)GlcNAc(2) glycans. This paper shows that monoglucosylated glycoforms of heavy chain, which exist transiently in the endoplasmic reticulum in the initial stages of the glycosylation processing pathway, are present in the peptide loading complex. The data are consistent with a model in which the release of peptide-loaded major histocompatibility complex class I molecules from calreticulin, induced by deglucosylation of the heavy chain N-linked glycan, signals the dissociation of the complex. This is consistent with the hypothesis that the class I loading process is an adaptation of the quality control mechanism involving calreticulin and ERp57.

Calreticulin↗

PubMed1984

The middle-class family and middle-class adolescents in a state of disarray: a social-psychiatric analysis.

Because mental health professionals tend to focus their attention on the complex of factors involved in the provision of psychotherapeutic and related services, they often do not give primary attention to the serious instabilities afflicting marriage and family among the middle class and are insufficiently aware of parents' deficiencies in rearing their children well. Moreover, they frequently underestimate the increasing prevalence of character defects and disorders and the acting-out problems they cause among middle-class adolescents and youths, who are widely involved in sexual activity, drug use, and theft and whose educational performance has sharply declined. Using a social-psychiatric perspective, this paper discusses the major sociocultural factors that greatly influence the problems straining and breaking up marriage and family among the middle class. It also examines the reasons for parental inadequacies that contribute heavily to their children's becoming impulse-dominated and involved in self-impairing and socially harmful problems.

Achievement↗

PubMed1996

Influence of anticoagulants on the level of soluble HLA class I and class II antigens measured in blood samples.

The existence of soluble forms of HLA class I and class II antigens in human serum is well established and altered concentrations of these serum proteins have been described to be associated with various diseases. Since soluble HLA antigens (sHLA) can be measured both in serum and plasma samples, we investigated whether anticoagulant treatment influences the determined levels of soluble HLA class I (sHLA-I) or soluble HLA-DR (sHLA-DR). Analyzing paired samples of serum and plasma of 40 healthy individuals we found significantly lower serum levels of sHLA-DR (0.31 +/- 0.15 ng/ml) compared to EDTA plasma levels (0.58 +/- 0.20 ng/ml). By contrast, serum levels of sHLA-I (0.89 +/- 0.74 micrograms/ml) were only slightly lower than EDTA plasma values (0.95 +/- 0.86 micrograms/ml), a situation similar to that of sIL-2R and sCD4 levels. Further experiments intended to clarify the reasons of the reduced sHLA-DR serum levels revealed that (i) the blood storage time before centrifugation did not influence the sHLA-DR level, (ii) treatment of serum with anticoagulant did not augment the measured sHLA-DR concentration, and (iii) the recovery of spiked sHLA-DR was significantly lower when added to native blood than to serum or anticoagulant-treated blood. These results suggest that sHLA-DR is partly removed by the process of blood clotting thus resulting in diminished sHLA-DR serum levels.

Anticoagulants↗

PubMed1989

Mixed isotype class II antigen expression. A novel class II molecule is expressed on a murine B cell lymphoma.

The structures of Ia molecules expressed by two BALB/c B cell lymphoma lines, A20-1.11 (A20) and 2PK3, were analyzed in an effort to explain the differences in antigen-presenting capacity displayed by these cells. Alloreactive T cell hybridomas specific for I-Ad and antigen-specific, I-Ad-restricted T cells responded well to A20 as the APC. The same alloreactive T cell hybridomas responded weakly or not at all to 2PK3 and the responses of the antigen-specific, I-Ad-restricted T cells were consistently lower to antigen presented by 2PK3 as compared with A20. T cells restricted to I-Ed responded equally well to either A20 or 2PK3 as APC. Additionally 2PK3, but not A20, stimulated a strong syngeneic mixed lymphocyte response. Structural analyses of the Ia antigens revealed that I-A and I-E molecules were expressed by A20, whereas an I-E and a novel I-A-like molecule were expressed by 2PK3. The novel class II molecule was affinity purified from 2PK3 cells using an mAb specific for Ad beta (MK-D6), and this molecule was subsequently shown by an RIA to react with an E alpha-specific mAb (14-4-4S) as well. Chain-specific polyclonal antisera raised against I-A and I-E alpha and beta chains indicated that the 2PK3 "I-A" alpha chain reacted in immunoblot with E alpha-specific and not A alpha-specific antisera, whereas the beta chain reacted with A beta- and not E beta-specific antisera. Peptide map and partial amino acid sequence analyses indicated that the "I-A" molecule expressed by 2PK3 represented a mixed isotype structure resulting from the pairing of Ed alpha with Ad beta. By immunofluorescence staining analysis, 2PK3 did not react with an mAb specific for Ad alpha. 2PK3 was capable of limited antigen presentation through the mixed isotype molecule to I-Ad-restricted OVA-specific T cell hybridomas, although the responses induced were low compared with presentation through I-A on A20. Previous descriptions of the expression of mixed isotype class II molecules in the mouse have resulted primarily from DNA-mediated gene transfer experiments. The results presented indicate that a mixed isotype class II molecule can be expressed naturally.

Animals↗

PubMed1990

Induction of peripheral tolerance to class I major histocompatibility complex (MHC) alloantigens in adult mice: transfused class I MHC-incompatible splenocytes veto clonal responses of antigen-reactive Lyt-2+ T cells.

The efficacy and the mode of action of pretransplant transfusion with class I major histocompatibility complex (MHC)-disparate splenocytes in establishing a state of peripheral tolerance in adult mice is analyzed. Adult mice injected intravenously with a critical number of approximately 5 x 10(7) allogenic splenocytes accept skin grafts and develop chimerism in the peripheral lymphatic tissues, but not in thymus and bone marrow. In parallel, a split tolerance evolves: the frequency of class I MHC-reactive Lyt-2+ cytotoxic T lymphocyte precursor (CTL-p)- and interleukin 2 (IL-2)-producing T cells falls off in the peripheral lymphoid tissue, but remains unaltered intrathymically. In particular, high affinity CTL-p become clonally undetectable. In vivo generation of tolerant cells is cyclosporin A resistant, but dependent on recipient L3T4+ T cells. Loss of Lyt-2+ CTL-p- and IL-2-producing T cell precursors is not due to active suppression, but is caused by clonal anergy. Donor-derived chimeric cells positively selected 7 d after intravenous transfusion exhibit in vitro the hallmarks of veto cells, i.e., paralyze CTL-p reactive to donor-type class I MHC alloantigens. We conclude that the peripheral (split) tolerance induced in vivo by pretransplant transfusion operates because donor-type cells develop in vivo efficiently into "veto cells," which in turn induce a state of clonal anergy within antigen-reactive Lyt-2+ T lymphocytes.

Animals↗