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R Wank

Publications and source records attributed to R Wank.

At least 55 records · Page 3Linked to original sources
PubMed1984

Identification of two cis-encoded HLA-DQ molecules that carry distinct alloantigenic specificities.

The monoclonal antibodies Genox 3.53, S1, and R1 define polymorphic epitopes localized to DQ molecules. All three antibodies showed a strong association with the HLA-DR antigens 1, 2, and w6 when tested on a panel of 68 unrelated individuals, suggesting that they all recognized the DQw1 allospecificity. However, segregation analysis and binding studies with a panel of HLA-D/DR homozygous cells indicated that these monoclonal antibodies defined two different alloantigens. Cells homozygous for DR 1, 2, or w6 expressed the epitopes defined by all three antibodies (i.e., S1, R1, and Ge) while cells homozygous for DR4 and DRw8 expressed only the S1 and R1 epitopes. Sequential immunoprecipitation analyses in S1+/R1+/Ge+ individuals, in which the three epitopes were shown by segregation analysis to be encoded by the same chromosome, revealed two distinct DQ-like molecules. While R1 and S1 appeared to reside on the same molecule, the epitope defined by Genox 3.53 was on a different molecule. Identical results were obtained with DR1-, DR2-, or DRw6-bearing cells. Thus it appears that DQw1-bearing individuals express two cis-encoded DQ-like molecules that carry distinct alloantigenic specificities.

Antibodies, Monoclonal↗
PubMed1984

Rare variant of complement C4 is seen in high frequency in patients with primary glomerulonephritis.

59 unselected patients with primary glomerulonephritis were phenotyped for alleles of the MHC-linked complement genes, C4A, C4B, and BF. A rare variant of the C4B locus, C4B*2.9, was found in 25% of these patients compared with only 2% of the normal population--a relative risk of 22.1 for glomerulonephritis in individuals with this variant. Subdivision of patients by histological classification of glomerulonephritis revealed a significant association of C4B*2.9 with the membranoproliferative form. There were no significant associations between primary glomerulonephritis or its subtypes and the other HLA markers tested.

Alleles↗
PubMed1984

Clonal expression of differentiation and Ia-like antigens on alloreactive human T lymphocytes.

A series of human T lymphocyte clones showing specific responses for major histocompatibility complex-encoded alloantigens were isolated from a single culture. They were classified into distinct functional groups based on measurement of alloantigen-specific proliferation and cytotoxicity. Surface antigen expression on these clones was analyzed using a panel of monoclonal antibodies specific for T cell differentiation antigens and for Ia-like antigens. Four distinct groups were identified based on the Leu series of differentiation antigens: (a) Leu1+,2+,3+,4+; (b) Leu1+,3+,4+; (c) Leu1+,2+,4+; and (d) Leu2+,4+. Functionally distinct clones showed not only differential expression of Leu2 and Leu3 , antigens which had previously been shown to distinguish helper/inducer and cytotoxic/suppressor cells, but also of Leu1, an antigen classified as a common T cell marker. All of the clones were found to express Ia antigens as detected by three framework monoclonal antibodies, but none were found to express a determinant associated with the DR3 allospecificity , although it was found on normal B lymphocytes and a B cell line established from the HLA-DR3 individual from whom these clones were derived.

Antibodies, Monoclonal↗
PubMed1984

Monoclonal antibodies to polymorphic epitopes on Ia antigens: three independent groups of determinants expressed on DRw6 homozygous cells.

Murine monoclonal antibodies directed against polymorphic epitopes on HLA-linked antigens were readily obtained following a single immunization with DRw6-homozygous cells. Five antibodies directed against class II antigens were isolated. Two precipitated DC-like molecules and 3 DR-like molecules from the immunizing lymphoblastoid cell line. Analysis of association with HLA-DR antigens in a panel of 60 individuals revealed 2 antibodies directed against the DC1 specificity (S1, R1) and one against the MT2 specificity (R3). Antibodies S2 and S3 showed significant association with DRw6 (chi 2 = 30.27) and DRw6 and w8 (chi 2 = 18.86), respectively. An analysis of 29 haplotypes indicated that epitopes defined by these monoclonal antibodies appear to identify polymorphic determinants on three independent gene products which can be encoded by a single HLA haplotype.

Animals↗
PubMed1984

Cultured human T lymphocyte lines and clones as immunogenetic tools.

Human T lymphocytes were sensitized in vitro to allogeneic determinants encoded by the HLA region and subsequently cloned by limiting dilution in the presence of human T cell growth factor. An in vitro priming protocol entailing multiple rounds of allostimulation in mixed lymphocyte culture, using a disparate stimulating to responding cell ratio (10:1), enabled a high frequency of functionally active clones to be isolated. The specificity of the proliferative and cytotoxic reactivities was ascertained directly by screening in an HLA characterized family.

Alleles↗
PubMed1984

MHC-linked class III genes. Analysis of C4 gene frequencies, complotypes and associations with distinct HLA haplotypes in German Caucasians.

The class III complement components, C4, C2 and factor B (BF), are encoded in the human major histocompatibility complex (MHC). The two genes determining C4 (C4A and C4B) display considerable polymorphism and, thus, are important markers for HLA. In combination with alleles of C2 and BF they can be grouped into unique complotypes. We have analyzed the C4 alleles in a panel of 204 unrelated German Caucasians and studied their segregation with HLA haplotypes in 24 normal families. Inclusion of the class III markers with the class I and II alleles provides a more refined picture of the genetic structure of the MHC in these families. When charted according to the HLA-B locus specificities the MHCs can be clustered into groups showing distinctly homogenous or heterogenous complotypes. The identification of such groups is valuable for the selection of genetic material to analyze the molecular genetics of the human MHC.

Complement C2↗
PubMed1982

Direct demonstration of an HLA-DR allotypic determinant on the low molecular weight (beta) subunit using a mouse monoclonal antibody specific for DR3.

A murine monoclonal antibody directed against a human B cell surface antigen with the characteristics of HLA-DR is described. The antigen detected is tightly linked to HLA and is correlated with the alloantigen HLA-Dw/DR3. Reactivity with a fraction of Dw/DRw6 cells is also observed. The determinant recognized by this antibody has been shown to be present on the smaller molecular weight beta subunit of the HLA-DR antigen.

Animals↗
PubMed1982

Rapid responses of lymphocytes in an optimized mixed lymphocyte culture.

When adherent mononuclear cells are removed from whole blood, the separated lymphocytes respond rapidly by proliferation to foreign cocultured lymphocytes. The reaction of responding cells against a pool of foreign stimulating cells can be detected in this rapid mixed lymphocyte culture (r-MLC) within 28 h and antigenic disparity between family members, differing for only one HLA haplotype, can be measured within 36 h. These early responses show genetic specificity corresponding to those observed in a standard MLC at 96 h. The involvement of similar cell populations in the regulation of early responses to allogeneic cells and increased responses to autologous cells in r-MLC, as well as accelerated responses in secondary MLC, is discussed.

Cell Division↗
PubMed1981

[Bone marrow transplantation for aplastic anaemia (author's transl)].

From March 1975 until May 1980 twelve patients with severe aplastic anemia were grafted with bone marrow from HLA-identical siblings by the Munich Cooperative Group for Bone Marrow Transplantation. Six patients are alive between 10 months and more than 5 years after grafting with normal blood values and marrow. One patient is treated as an out patient for chronic localized graft-versus-host disease (GvHD), five patients are well and without treatment. Six patients have died, one patient with a cerebral hemorrhage the day before transplantation, three patients following rejection of grafts 32, 40 and 55 days after grafting, one patient with severe GvHD 85 days after grafting and one patient, probably with interstitial pneumonia, following cerebral hemorrhage. Three of 6 patients who were conditioned with Cyclophosphamide (CY) only died following rejection of the graft. Two adults who were conditioned with CY and "total lymphoid irradiation" and three children, who wer given unirradiated leukocyte concentrates from the marrow donor after grafting, did not reject their grafts. The results of the Munich-Cooperative Group for Bone Marrow Transplantation are comparable to those of large, specialized centers for bone marrow transplantation, they indicate possibilities of cure of severe aplastic anemia by marrow grafts from HLA-identical siblings. They confirm that better results are obtained with earlier transplantation in the course of the disease.

Adolescent↗
PubMed1981

Production of human T cell growth factor.

We provide here a protocol for production of T cell growth factor (TCGF) using cells isolated from defibrinated blood. Whether combined in allogeneic pools or tested as single donors, these cells consistently yield high activity TCGF, following PHA stimulation. Protocols using cells isolated from heparinized blood have often included addition of indomethacin or removal of adherent cells, or both, to overcome the problem of frequent nonproducing cultures. Our failure to find nonproducing cultures using this source of cells suggests that inhibitory cells or factors are removed by the blood clot formed during defibrination. A distinct economic advantage is gained by using these cells, not only because of the reliability of obtaining active supernatants, but also because the same blood can be used for preparation of a serum pool for cell cultures and the erythrocytes are useful for absorption of contaminating PHA present in the TCGF-containing media. Not only can defibrinated blood leukocytes be stimulated by PHA to release TCGF, but when cultured in allogeneic mixtures containing no PHA, they also release active TCGF.

Culture Media↗
PubMed1981

Noncodominant expression of target antigens recognized by human cytotoxic T lymphocytes.

Human CTL that recognized MHC-controlled determinants distinct from HLA-A. B, C, and D/DR antigens were tested in a family with nine siblings. Segregation analysis of positive CML reactions showed strong lysis of target cells of three HLA-identical siblings, inheriting the b and c MHC haplotypes (blc), but not of the parents or siblings inheriting only one of these haplotypes. Some cytotoxicity was seen against parental target cells, although it seemed to be qualitatively distinct from that directed against the b/c targets. Studies using the competitive inhibition technique showed that cells inheriting only the b or c haplotypes were not effective in decreasing the specific cytotoxicity. Furthermore, simultaneous inclusion of inhibitor cells of both the b and c haplotypes did not hinder the specific cytotoxicity. Induction of CTL recognizing this new determinant did not occur when either antigens of the b or c haplotypes were used as MLC stimulating cells, or when antigens of both haplotypes were presented simultaneously, but on separate stimulating cells, in a three-cell MLC. These results suggest that the target determinant recognized by these unusual CTL is complex; it may be formed through interactions of two surface molecules or by genetic complementation yielding a hybrid antigen.

Binding, Competitive↗
PubMed1981

Isolation of HLA-haplotype-specific human T-lymphocyte clones.

Human T-lymphocyte clones showing proliferative and cytotoxic responses specific for HLA antigens were isolated. To obtain enriched numbers of functionally active colonies, the cells were first sensitized in vitro in a tertiary mixed lymphocyte culture (MLC), using 10 stimulating cells for each responding cell. To assess quickly the genetic specificity of the clones, the cells used in the priming MLC and later as screening cells were prepared from an HLA-typed family. Using this approach, 75% of the colonies seeded at 1 cell/well showed functional activity specific for HLA.

Cell Separation↗
PubMed1981

Cell-growth kinetics and karyotype analysis of human memory lymphocytes responding to alloantigen and mitogen.

Peripheral-blood lymphocytes were primed in vitro with the mitogen phytohemagglutinin (PHA) or with allogeneic cells and their memory responses studied following sequential restimulation with either mitogen or alloantigen. Chromosome preparations were made every 24 hours following exposure to the stimulating agents. Cultures were labeled with BUdR for sister-chromatid staining of the chromosomes which provided information about the kinetics of cell growth and rates of sister chromatid exchange. Cultures containing n BUdR were used for the investigation of cell karyotypes after chromosome-banding. Following PHA as well as alloantigen restimulation, an earlier reaction of the responding cells was observed. The peak response after the first stimulation was found at 120 h with allogeneic stimulation and at 60 h with mitogen stimulation. In the second round of stimulation, the peak occurred after 48 h (allogeneic) and 36 h (PHA) and following the third stimulation after 36 h (allogeneic) and 24 h (PHA). The speed of cell growth was decreased following restimulation with either alloantigen and mitogen. In contrast to the allogeneic restimulation, the number of cells responding after PHA restimulation was decreased. No systematic numerical or structural aberration of the karyotype was detected following repeated stimulation with either alloantigen or mitogen. In this sense, the lymphocyte subpopulations selected by repeated stimulation did not differ from the starting material. On the other hand, the sister-chromatid exchange (SCE) frequency was increased following allogeneic restimulation, whereas it remained constant with PHA restimulation.

Humans↗
PubMed1980

Genetic specificity of primary and secondary proliferative and cytotoxic responses of human lymphocytes grown in continued culture.

Human T peripheral blood lymphocytes were grown in continued culture using conditioned medium obtained from phytohaemagglutinin-stimulated, pooled human leucocytes. These cultured T cells (CTC) were tested in mixed lymphocyte culture (MLC) and cell-mediated lympholysis (CML) assays to determine the genetic specificity of their proliferative and cytotoxic responses. Primary responses were measured after initial in vitro stimulation by allogeneic cells, and secondary responses were measured after a second in vitro stimulation by allogeneic cells. Both primary and secondary proliferative responses were found to be stimulated by alloantigens controlled by the HLA region and, more specifically, by antigens of the HLA-D region, in accordance with the responses of normal peripheral blood T lymphocytes. When CTC were established from unsensitized PBL and then stimulated with allogeneic cells, they could respond by proliferation in MLC, but, in contrast to PBL, they did not show subsequent cytotoxic responses. On the other hand, CTC established from PBL that had been stimulated first with allogeneic cells in either primary or secondary MLC displayed high levels of cytotoxic reactivity in CML. The strongest cytotoxicity was directed against allospecificities controlled by the HLA region and specific for the MLC-stimulating cells, but lower levels of cross-reactive cytotoxicity were also observed.

Cells, Cultured↗
PubMed1980

[Selection of donors for bone marrow transplantation in childhood leukemia (author's transl)].

The problems of immunological donor selection for bone marrow transplantation (BMT) are discussed: In acute childhood leukemia, the possibility of BMT should be discussed already at the time of diagnosis, in case the orthodox treatment of leukemia is not successful. The tests for donor selection should best be done during the first remission and should include the antigens of HLA-A,B,C,DR and D-loci as well as the Bf and GLO-Systems. It is important to include in the tests as many as possible first degree relatives in order to establish the inheritance of the HLA-Antigens. If there is no HLA-genetically identical sibling, it also possible to consider other relatives, provided there is genetic identity for one HLA-Haplotype and chance-compatibility for the other haplotype.

Acute Disease↗
PubMed1979

Secondary MLC responses of primed lymphocytes after selective sensitization to non-HLA-D determinants.

Two HLA-B,D-identical siblings, who differed only for the HLA-A region because of a maternal recombinational event, were studied in primary (1 degrees) and secondary (2 degrees) mixed lymphocyte culture (MLC). The HLA-A:B recombinant child did not respond to its HLA-B,D-identical sibling in either 1 degrees or 2 degrees MLC. In the reciprocal combination the non-recombinant child responded only weakly in 1 degrees MLC but responded significantly in 2 degrees MLC to the HLA-A:B recombinant child. Thus, it was possible to selectively prime to a non-HLA-D determinant, which is controlled by a gene located distal to HLA-B. Because this determinant was not present on T-cells, it could be distinguished from the serologically defined antigen controlled by the HLA-A locus. Such primed lymphocytes, as well as lymphocytes primed between HLA-identical siblings, revealed high autologous control responses which were not observed when using lymphocytes primed in conventional one-haplotype combinations. The significant 2 degrees MLC response to autologous cells after sensitization to allogeneic cells may reflect recognition of self antigens and raises the question to what extent genetic similarity between responding and stimulating cells is required in the priming phase to elicit a 2 degrees response to autologous cells.

Child↗