Biomedical subjects

A Termijtelen

Publications and source records attributed to A Termijtelen.

At least 37 records · Page 2Linked to original sources

PubMed1989

Specific suppression of mixed lymphocyte reactions by alloactivated cells is correlated with cytotoxicity.

Mixed lymphocyte reaction (MLR)-activated lymphoblasts can suppress both proliferation and the induction of cell-mediated lysis (CML) when added to a subsequent MLR. Antigen specificity and the mechanism of MLR-induced suppression was investigated, with special emphasis on the exclusion of cell-mediated stimulator cell lysis as the cause of suppression. We studied the suppressive properties of nine MLR-activated cultures, selected because of their specific suppressive properties. Suppression of a given MLR was obtained when the stimulator cell carried at least one of the mismatched HLA antigens of the original stimulator. The mismatched antigen which activated suppression was an HLA class I antigen in 3 out of 9 cases, an HLA class II antigen in another 3 cases. In the remaining 3 cases suppression was observed when either an HLA class I or an HLA class II antigen was shared between the original stimulator and stimulator cell of the MLR. When analyzed on the same panel, a positive linear correlation between suppression of an MLR and CML activity against the stimulator cell was found. We also observed that both the original MLR (A*B) and the reserve MLR (B*A) could be suppressed by these anti-A suppressor cells. These results are compatible with the hypothesis that in the protocol studied suppression is mediated by lysis of the stimulator cells.

Cytotoxicity, Immunologic↗

PubMed1988

Functional polymorphism of each of the two HLA-DR beta chain loci demonstrated with antigen-specific DR3- and DRw52-restricted T cell clones.

HLA-DR3- and HLA-DRw52-associated functional polymorphism was investigated with selected tetanus toxoid (TT)-specific T cell clones. We have shown earlier that HLA-DR antigens are encoded by two distinct loci, DR beta I and DR beta III. The alloantigenic determinant(s) defined by the serological HLA-DR3 specificity map to the former, while the supratypic HLA-DRw52 determinants map to DR beta III. Furthermore, we have recently recognized by DNA sequencing three alleles of HLA-DRw52 at locus DR beta III, referred to as 52 a, b, and c. Our objective was to correlate the pattern of T cell restriction with the gene products of individual DR beta chain loci and with the three newly described alleles of locus DR beta III. Among the selected T cell clones, 5 reacted exclusively when TT was presented by HLA-DR3+ APCs (TT-DR3-APC). In contrast, two T cell clones were stimulated by TT-DRw52-APC. More specifically, these two T cell clones (Clones 10 and 16) were stimulated by different subsets of TT-DRw52-APC. Clone 16 responded to some DR3 and TT-DRw6-APC, while clone 10 was stimulated by other TT-DR3 and TT-DRw6, and all TT-DR5-APC. This same pattern of DRw52 restriction was found in panel, as well as in family studies. Because this suggested a correlation with the pattern of DRw52 polymorphism observed earlier by DNA sequencing and oligonucleotide hybridization, the APC used in these experiments were typed for the 52 a, b, and c alleles of locus DR beta III by allele-specific oligonucleotide probes. This distribution overlapped exactly with the stimulation pattern defined by the T cell clones. Clone 16 responded to TT-52a-APC, clone 10 to TT-52b-APC, and both clones to a TT-52c-APC. The response of the T cell clones was inhibited differentially by mAbs to DR. Raising TT concentration, or increasing HLA-class II expression with INF-gamma both affected the magnitude of response of the TT-specific clones but did not modify their specificities. These results demonstrate that a restriction specificity can be attributed to the DR beta III locus and illustrate the functional relevance of the polymorphism observed at this locus. This is of special interest in view of the striking difference in the pattern of structural diversity among alleles of DR beta I and DR beta III.

Alleles↗

PubMed1988

Polymorphism and complexity of HLA-DR: evidence for intra-HLA-DR region crossing-over events.

HLA-DR molecules were isolated from HLA-DR3, -5, and -w6 positive homozygous B-cell lines by immunoprecipitation with monoclonal antibodies and analyzed by gel electrophoretic techniques. DNA isolated from the same cell lines was digested with the restriction enzyme Taq I and hybridized with a DR beta full-length cDNA probe. We demonstrated that certain DR beta I alleles are found in combination with different DR beta III alleles as defined by Southern blotting, protein chemistry, a functional assay using purified protein derivative-specific T-cell lines, and, in one case, also alloreactive T-cell reagents. Our results indicate that within the family of HLA-DRw52-associated haplotypes DR beta chain genes may have been transferred from one haplotype to another. The implications of these findings are discussed.

Alleles↗

PubMed1988

Correlations between polymorphisms at the DNA and at the protein level of DRw52 haplotypes, revealed with a variety of techniques.

LB-Q1 and LB-Q4 are two subtypes of DRw52, defined by proliferative T-cell clones. These subtypes represent a polymorphism of the DR beta III gene. Similar subtypes of DRw52 can be defined by oligonucleotide typing, serology and RFLP analysis. In the present study we compared these typing techniques on a panel of 22 HLA-D homozygous, DRw52-positive typing cells. All typing techniques correlated very well. Three subtypes of DRw52 could be identified. Our results show that typing for cellularly defined structures can be done with a variety of noncellular techniques. This observation has important implications for matching in unrelated bone marrow transplantation and for disease association studies.

DNA↗

PubMed1988

HLA-DR beta III and HLA-DP induce comparable proliferation in primary mixed lymphocyte culture.

To study the stimulatory capacity of HLA-DR beta III in the mixed lymphocyte culture (MLC) assay, an MLC matrix between 13 Dw18 homozygous typing cells (HTCs) was analysed. Six of these HTCs were positive for the HLA-DR beta III allele LB-Q1 as defined by T cell clones. Seven HTCs were positive for LB-Q4. The MLC responses between Dw18 HTCs, matched for LB-Q, were significantly lower than the responses between the mismatched combinations. Considering the fact that HLA-DP can induce proliferation in MLC, we then analysed the DP matched and mismatched combinations separately. The influence of HLA-DR beta III mismatches was in our experiments comparable to the influence of mismatches for HLA-DP. Surprisingly, 15 out of 22 DR beta III and DP matched combinations still showed positive MLC reactions.

Cells, Cultured↗

PubMed1987

T-cell prolymphocytic leukemia with an unusual phenotype CD4+ CD8+.

A patient with T-cell prolymphocytic leukemia (T-PLL) is described. The outcome was poor, with death 8 months after diagnosis, despite several therapeutic interventions. The cells carried both CD4 and CD8 epitopes, but other thymocytic markers were absent. The spleen showed infiltration of CD4+ CD8+ prolymphocytes in the red pulp and in T-cell-dependent areas of the white pulp. Immunologic function studies revealed proliferation after stimulation with mitogens and even several antigens. However, in the mixed lymphocyte culture the T-PLL cells did not proliferate. Cytotoxic T-cells could not be induced. In T-non-T recombination experiments neither helper nor suppressor cell function was found for pokeweed mitogen-dependent plasmablast generation of normal B-cells. Cytogenetically, many abnormalities were found. Among them, 14q+; absence of chromosomes 8, 11, and 22; and the presence of large marker chromosomes and fragments.

Aged↗

PubMed1987

Molecular localization of LB-Q1, a DRw52-like T-cell recognition epitope and identification at the genomic level of associated shared hybridizing fragments.

In this paper we report on the molecular localization of LB-Q1, a supertypic HLA class II determinant which we previously identified by the use of proliferative T cells. The population distribution shows that each of the DRw52 associated specificities DR3, DR5, and DRw6 may occur with and without LB-Q1. DNA from nine DR3, six DR5, and 14 DRw6 homozygous B-cell lines were digested with the enzymes TaqI, EcoRI, and PvuII. Using a DR beta cDNA probe, shared hybridizing fragments were observed that correlate completely with the presence or absence of LB-Q1. T-cell recognition of LB-Q1 can be blocked with a monoclonal antibody (7.3.19.1) which in some haplotypes selectively reacts with the DR beta III chains, but cannot be blocked with a monoclonal antibody (I-LR2) reacting in those same haplotypes exclusively with DR beta I chains. Therefore, LB-Q1 maps to the DR beta III molecule. These data suggest the occurrence of relatively frequent previous recombinations between the two DR beta chain genes present in DRw52 haplotypes.

Antibodies, Monoclonal↗

PubMed1987

Polymorphisms within the HLA-DRw6 haplotype. III. DQ alpha and DQ beta polymorphism associated with HLA-D.

We have studied HLA-DQ encoded antigens from HLA-DRw6 homozygous cells and analyzed the DQ region at the DNA level. HLA-DQ molecules were isolated from EBV transformed B-cell lines and analyzed for DQ alpha and DQ beta polymorphism. From the same set of cells, DNA was isolated and analyzed for RFLP. Polymorphism could be detected by both techniques, i.e., on the protein level and on the DNA. The variation in pI of the DQ alpha and beta chains correlated with the polymorphism as detected by HTC typing, as did the variation in molecular weight of the bands hybridizing to DQ specific cDNA probes; identical patterns were detected for cells of one HLA-D specificity and different patterns for different HLA-D types. Additionally, DQ reactive PLT reagents were raised against DRw6 positive cells. Panel studies revealed that these DQ reactive proliferative T cells can discriminate between the polymorphic DQ antigens on cells with different HLA-D specificities.

Antibodies, Monoclonal↗

PubMed1987

Evidence that the difference in kidney graft survival in DRw6+ and DRw6- recipients may be explained by a blood transfusion policy that is disadvantageous for DRw6+ recipients.

Kidneys transplanted to HLA-DRw6+ recipients have been shown to have an inferior graft survival compared with DRw6- patients. Because pretransplant blood transfusions influence kidney graft survival, we investigated whether the number of blood transfusions contributes to the observed poor graft survival in DRw6+ patients. We have found that the difference in graft survival in DRw6+ and DRw6- recipients may be explained by a blood transfusion policy that is disadvantageous for DRw6+ recipients. Thus, graft survival in DRw6+ recipients was excellent for those who had received only a single transfusion. More transfusions resulted in a gradual decrease in graft survival. When the number of transfusions exceeded 5, graft survival improved again. By contrast, DRw6- recipients showed an improvement in graft survival with an increasing number of transfusions. DRw6+ recipients therefore display inferior graft survival only when they receive 3-5 transfusions. This finding provides a possible explanation as to why the "DRw6 effect" is a controversial issue, and it suggests that DRw6+ recipients should be given a different pre-transplant transfusion protocol than DRw6- patients.

Cyclosporins↗

PubMed1987

Differential expression of DRw52-like determinants detected by monoclonal antibodies.

The reactivity of three monoclonal antibodies (MoAb) directed against DRw52-like determinants was studied in relation to the reactivity of an anti-DR MoAb using fluorescence-activated cell sorter (FACS) analysis. The MCS-7 MoAb reacted with all DRw52+ cells and in addition with DR2+, DR4+, and a DR7+ cell. Both the I-LR2 and the 7.3.19.1 MoAb reacted with DR3+, DR5+, and DRw6+ cells only. However, whereas the 1-LR2 MoAb reacted strongly with all those cells compared with the anti-DR MoAb, the 7.3.19.1 MoAb reacted strongly with DR3+ cells only, and somewhat less with DR5+ and DRw6+ cells. The implications of this for the location of DRw52-like determinants on DR beta chains is discussed.

Antibodies, Monoclonal↗

PubMed1987

Matching for supertypic DR epitopes does not reduce mixed lymphocyte culture reactivity.

It was recently demonstrated that matching for the supertypic DR specificities DRw52 and DRw53 significantly improved graft survival in a group of retrospectively typed kidney transplant patients. We investigated whether this phenomenon was also reflected in vitro in the mixed lymphocyte culture (MLC) test system. MLC matrices were set up, but no effect of the matching between responder and stimulator for DRw52 and DRw53 was observed, although matching for the DR 'private' specificities (DR1-DRw10) was significant. In responder-stimulator combinations, too, which were mismatched for 1 DR antigen only, it did not matter whether or not the mismatched antigen on the stimulator was DRw52 or DRw53 compatible to the responder. These findings imply that matching for supertypic DR epitopes does not necessarily lead to reduced MLC reactivity.

Epitopes↗

PubMed1986

Polymorphisms within the HLA-DR3 haplotypes. I. HLA-DR polymorphisms detected at the protein and DNA levels are reflected by T-cell recognition.

HLA-DR molecules were isolated from eight different HLA-DR3 homozygous B-cell lines by immunoprecipitation with monoclonal antibodies, and they were subsequently analyzed by two-dimensional gel electrophoresis. We found that HLA-DR3 homozygous B-cell lines of consanguineous origin express two types of HLA-DR molecules. One type of HLA-DR molecule was present in all the cell lines tested, whereas the second DR molecule appears to be polymorphic. DNA isolated from the different HLA-DR3 homozygous cell lines was studied by Southern blot analysis to determine whether any DR beta restriction fragment length polymorphism could be observed. Polymorphisms detected at both the product and genomic level have been compared to each other, and their relations to the serological (HLA-DR) and cellular (HLA-D and LB-Q1) typing data will be discussed.

Antibodies, Monoclonal↗

PubMed1985

Polymorphisms within the HLA-DRw6 haplotype. II. Protein charge heterogeneity reflects MLC subtyping of HLA-DRw6 homozygous cells.

We have analyzed the HLA class II gene products from HLA-DRw6 homozygous cells. Epstein-Barr virus-transformed B-cell lines were internally labeled with [35S]-methionine. An NP-40 lysate of the cells was subjected to immunoprecipitation, first with a DRw52-like-specific monoclonal antibody and subsequently with a DR-specific framework antibody. The DR region-encoded gene products were analyzed by one-dimensional gel isoelectric focusing and two-dimensional gel electrophoresis. It is shown that DRw6 homozygous cell lines contain at least two nonallelic DR beta chains, one carrying a DRw52 determinant and one DRw52-negative population. Both chains appear to be polymorphic between the cellularly defined subtypes of DRw6. The determinant responsible for the differential mixed lymphocyte culture reactivity of Dw18 and Dw19 cells resides on the DRw52-positive population, whereas the Dw6-Dw9 differences are attributed to determinants on both populations of DR light chains. The Dw16-derived DRw52+ chain much resembles the Dw18 DRw52+ light chain whereas there is a clear-cut difference between these two subtypes in the DRw52- population. We conclude that, for DRw6 homozygous cells, the cellularly recognized D determinants are probably located on DR-encoded molecules, both DRw52+ and DRw52-, and that charge shift of these chains is at least partly responsible for differential recognition of these cells in mixed lymphocyte cultures.

Epitopes↗

PubMed1985

HLA class II restriction repertoire of antigen-specific T cells. II. Evidence for a new restriction determinant associated with DRw52 and LB-Q1.

We have studied the HLA class II restriction repertoire of antigen-specific T lymphoblasts (T-LB) in response to purified protein derivative (PPD) and tetanus toxoid (TET), presented by allogeneic antigen-presenting cells (APC). In 102 fully DR(1-w14) mismatched T-LB/APC combinations matching for DRw53 (MT3) had a significant influence on T-LB proliferation (p = 0.0005). Moreover, the supertypic specificity DRw52 (MT2) and LB-Q1 (a new class II determinant in strong linkage disequilibrium with DRw52) appeared to be markers for a new RD (p less than 0.0005). LB-Q1 was most strongly associated with this RD and among DRw52 identical T-LB/APC combinations additional LB-Q1 sharing significantly increased T-LB responsiveness (p = 0.02). DRw52- and LB-Q1-restricted responses could be inhibited by an anti-DRw52 and an anti-DR framework monoclonal antibody, indicating that DR(w52), LB-Q1, and the new RD are located at the same molecule.

Antibodies, Monoclonal↗

PubMed1985

Recognition of DP determinants with typing reagents prepared with lymphocytes from Dutch unrelated individuals.

In an attempt to make our own set of DP typing reagents, we used lymphocytes from 12 unrelated donors, who were all HLA-A1,2; B7,8; DR2,3; DQW1,2. They all had been previously typed for DP using a reference set of well established reagents obtained from Dr. S. Shaw (NIH, Bethesda). Thirty-six promising responder-stimulator combinations were primed in bulk MLC and tested for their specificity in secondary MLC. All reagents gave reaction patterns which were concordant with the sensitizing DP types, with the exception of those combinations where a donor was used in which DR2 appeared to be associated with a non-DW2 HLA-D type. Over 1,200 reactions obtained with the new reagents were compared with those obtained with the established ones, in six different experiments. High correlation coefficients (r values) were found between the two kinds of reagents. The typings of a panel of individuals with the reference set and with our new typing set revealed an excellent agreement for DP assignments with the two sets, with the exception of the specificity DP4. The DP gene frequencies for random Dutch Caucasoids were defined.

Gene Frequency↗

PubMed1985

Polymorphisms within the HLA-DRw6 haplotype. I. Restriction fragment length variation and its correlation with serology.

The Dw6/DRw6 complex, one of the MHC class II specificities that can be defined by cellular techniques and by serology, probably has one or more immunoregulatory functions. To obtain information on the molecular structure of the DRw6 region, we studied several DRw6 homozygous cell lines, of which three were of consanguineous origin. DNA-DNA hybridization comprised the use of seven restriction enzymes in combination with three DR beta cDNA probes. The obtained results were compared with similar analyses of an HLA homozygous cell panel, expressing DR1-w8 specificities. This comparison indicated that in DRw6 homozygous individuals the coding potential for DR beta chains resembles closely that of all other DR specificities, thus identifying DRw6 as a regular DR region. In addition, we found a restriction fragment length pattern unique for DRw6, indicating the possibility to type for DRw6 by DNA-DNA hybridization. Comparisons within the DRw6 cell panel revealed the occurrence of several HLA class II DNA subtypes. These subdivisions partly correlated with serologically obtained reaction patterns. No correlation, however, could be observed between the different DNA subtypes and cellular reaction patterns as obtained by MLC and T cell cytotoxicity.

Antigen-Antibody Reactions↗

PubMed1984

The influence of matching for SB on MLC typing is significant but marginal.

To investigate the role of SB in MLC typing responses, reactions of lymphocytes from 23 DW3-positive, HLA-D-heterozygous individuals against 9 Dw3 homozygous typing cells (HTCs) were evaluated. Significantly more clear typing reactions were observed in those combinations that were matched for SB as compared with those that were mismatched. Nevertheless, MLC responses towards HTCs that were HLA-D/DR- and SB-compatible could be very strong. An additional analysis of the influence of HLA-B and the newly defined determinants LB-Q1 and LB-Q2 demonstrated that in combinations that were matched for these markers as well, stabilized relative responses could still be over 100%.

HLA Antigens↗

PubMed1984

Relation of insulin-dependent diabetes mellitus (IDD) and the HLA-linked SB system.

This report deals with the question of the susceptibility for IDD association with the recently described HLA-linked SB system. The SB system is located centromeric of HLA-DR between HLA-DR and GLO. At present five specificities of the SB system, which behave as alleles, can be recognized. A total of 40 IDD patients and 96 normal controls were characterized for HLA-A, -B, -C, -DR and SB antigens. Our results confirmed the strong positive association of IDD with HLA-DR3 and -DR4 and the negative association of IDD with HLA-DR2. The genetic analysis of the SB system and IDD, however, demonstrated no significant association between alleles of SB and susceptibility for IDD. The analysis of association between alleles of HLA-DR and SB revealed no significant linkage disequilibrium in IDD patients and a significant linkage disequilibrium between SB1 and HLA-DR3 in the controls. These results suggest that the genes associated with susceptibility for IDD are primarily coded for telomeric of SB and tightly linked with HLA-DR.

B-Lymphocytes↗