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Biomedical subjects

G Riethmüller

Publications and source records attributed to G Riethmüller.

At least 199 records · Page 11Linked to original sources
PubMed1986

Tumor necrosis factor as effector molecule in monocyte mediated cytotoxicity.

A newly developed assay system which uses actinomycin D (Act D) pretreated Wehi 164 target cells allows for the measurement of human monocyte cytotoxicity in a 7-h 51Cr release assay. Using the monocyte specific monoclonal antibody M42 in a direct rosetting procedure we confirm herein that among human peripheral blood mononuclear cells cytotoxicity is restricted to monocytes. When applying stringent conditions that exclude exogenous lipopolysaccharide (LPS) we could demonstrate that as little as 0.1 ng of LPS per ml triggers this cytotoxicity. Further, a factor can be detected in supernatants of mononuclear cells which is also cytotoxic against Act D treated Wehi 164 cells. This cytotoxic factor can be triggered by LPS within 4 h, but at as low a LPS concentration as 0.001 ng/ml. Since one of the LPS triggered monocyte products is tumor necrosis factor (TNF), we tested the effect of recombinant TNF cloned from the U937 cell line and we could show potent lytic activity against Act D pretreated but not, or only minimally, against untreated Wehi 164 target cells. Recombinant TNF rapidly lysed the target with significant specific release occurring as early as after 3 h in the assay. By contrast, recombinant interleukin 1 gave no lysis while lymphotoxin derived from the RPMI 1788 cell line was effective. An affinity purified antiserum directed against TNF neutralized the lytic activity of recombinant TNF and also the cytotoxic factor produced by LPS triggered mononuclear cells, while the antiserum was ineffective against lymphotoxin. Further, the antiserum when added to the assay of effector cells and Act D treated Wehi 164 cells also completely ablated cytotoxic activity. Size fractionation of cytotoxic factor and recombinant TNF by high pressure liquid chromatography led to a superimposable peak of cytotoxicity in the molecular weight range of 9,500-17,000. Further, immunoblotting with the anti-TNF antibody revealed the same Mr 15,500-16,500 band for the recombinant TNF and LPS triggered cytotoxic factor. Taken together, our data demonstrate that the cytotoxic activity of human monocytes against Act D treated Wehi 164 is mediated entirely by a LPS triggered molecule that is very similar or identical to the human tumor necrosis factor. The assay system thus provides a powerful tool to analyze the biology of TNF in humans.

Cytotoxicity, Immunologic↗
PubMed1985

Infiltrating mononuclear cells in human breast carcinoma: predominance of T4+ monocytic cells in the tumor stroma.

Frozen sections of 52 breast carcinomas were examined for the presence and nature of a leukocytic infiltrate. The number of "common leukocyte (T200-) antigen"-bearing cells was remarkably high in the stromal compartment of the carcinomas, whereas the tumor foci themselves were usually infiltrated only sparsely. Approximately 80% of these T200+ stromal cells carried the myelomonocyte lineage-associated antigens M-M522 and 63D3 and exhibited "non-specific esterase" activity. More than 2/3 of the stromal monocytic cells expressed the T4 antigen as verified by monoclonal antibodies (MAbs) directed against different T4-associated epitopes. A T-cell analysis showed that T4+ cells clearly outweighed the total number of T cells as defined by anti-T3 and anti-TII antibodies. In addition, a correlation became apparent between the HLA-DR phenotype and the T lymphocyte content of tumor cell areas in the sense that densely infiltrated tumor areas were invariably HLA-DR+.

Animals↗
PubMed1985

In situ analysis of antigens on malignant and benign cells of the melanocyte lineage. Differential expression of two surface molecules, gp75 and p89.

Monoclonal antibodies (mAb) were selected for differential binding to sections of freshly frozen biopsy material of human malignant melanomas and their precursor lesions, the melanocytic nevi. Both melanomas and normal nevi expressed human Ia-like antigens, transferrin receptor and the transferrin-related molecule p97. In contrast, only 1 nevus of 21 tested expressed both glycoprotein gp75, defined by mAb 15.75, and protein p89, defined by mAb P3.58, whereas 12 of 15 melanomas tested expressed both antigens. mAb P3.58 reacted with one additional melanoma and one nevus. The expression of these two molecules therefore appears to be correlated with the appearance of the malignant phenotype of melanocytes.

Animals↗
PubMed1985

Detection of coronavirus-like particles in homosexual men with acquired immunodeficiency and related lymphadenopathy syndrome.

Coronavirus-like particles were identified by electronmicroscopy in the feces of homosexual men. The particles banded at a density of 1.21 g/ml after cesium chloride density gradient centrifugation. To determine whether the presence of this virus might be related to clinical symptoms, several patient groups were studied prospectively. In 8 of 16 (50%) homosexual males with acquired immunodeficiency syndrome (AIDS) or unexplained lymphadenopathy syndrome (LAS), coronavirus particles were found. In contrast, such particles were found in none of 18 heterosexual controls and in only 3 of 20 homosexual males without AIDS or LAS. Thus, coronavirus excretion correlated significantly (2 alpha less than 0.01) with the clinical diagnosis of AIDS or with syndromes belonging to the AIDS-related complex. In addition, such particles identified in the serum of one patient with LAS and diarrhea suggest invasion and systemic spread of the agent and underline that this virus behaves differently from "common cold" human coronaviruses.

Acquired Immunodeficiency Syndrome↗
PubMed1985

In-vitro induction of some features of hairy cell leukemia in chronic lymphocytic leukemia and immunocytoma cells.

In an attempt to induce in vitro differentiation we exposed cells from patients with chronic lymphocytic leukemia (CLL) and with immunocytoma (IC) to 12-0-tetra-decanoylphorbol-13-acetate (TPA) at 160 nM. After 3 to 5 days of culture cells became enlarged and the CLL cells developed a basophilic cytoplasm with an excentric nucleus. In some instances cells with many fine projections were seen. We then employed the monoclonal antibody (MAB) HD 6, which was generated against hairy cell leukemia (HCL) cells and reacts most strongly with such cells but is unreactive with plasmocytoma cells and with most CLL cells. TPA treatment induced a greatly enhanced HD 6 binding in CLL and IC cells compared to controls as demonstrated by indirect immunofluorescence. Cytochemical studies revealed that at the same time an acid phosphatase was induced, which was found to be tartrate-resistant in every instance tested. Thus, several features of HCL can be induced in CLL and IC demonstrating the close relatedness of these entities.

Cell Differentiation↗
PubMed1985

Organization, sequence and expression of the HLA-B27 gene: a molecular approach to analyze HLA and disease associations.

Among the numerous autoimmune diseases associated with various HLA alleles, the one with the highest relative risk so far reported has been ankylosing spondylitis with HLA-B27. To examine this relationship more directly, we have cloned the gene encoding the HLA-B27 antigen and determined its complete DNA sequence. Comparison of the HLA-B27 sequence with that of the allelic HLA-B27 shows a high level of homology. Mutations are distributed evenly between exons and introns. Exon 1 and intron 1 are the most divergent ones, and the degree of divergence distinctly declines towards the 3' end. The HLA-B57 gene when transfected into murine L cells is expressed on the cell surface and reacts with a panel of monoclonal antibodies directed against monomorphic and polymorphic determinants associated with HLA-B27 antigen. The isolation of this gene allows for the first time a search for structural features which make the HLA-B27 antigen a high risk genetic factor for a group of rheumatoid disorders, in particular ankylosing spondylitis.

Amino Acid Sequence↗
PubMed1985

Antigenic relationship between the alpha-chain of C3, a leucocyte-surface antigen involved in the activation of phagocytic cells, and a 50,000 MW B-cell antigen.

A monoclonal antibody, M522, reacting with human monocytes, neutrophils and a proportion of non-adherent PBL in a pattern similar to OKM-1 and anti-Mo-1, and precipitating a dimer of MW 165,000 and 100,000 from neutrophils, was shown to react with C3 at an epitope localized on the alpha-chain of C3. F(ab)2-fragments of M522 stimulate the respiratory burst of neutrophils and monocytes. M522 differs from two monoclonal antibodies against the Mo-1 molecule with respect to the capacity to inhibit the binding of sheep erythrocytes coated with different C3-fragments to C-receptor carrying cells. It inhibited the binding of H-coated particles to B-lymphoid cells and precipitated a 50,000 MW molecule from RAJI cells and tonsil lymphocytes. The results obtained suggest an antigenic relationship between the alpha-chain of C3, the heavy chain of a membrane molecule involved in neutrophil/monocyte activation, and a B-cell molecule of MW 50,000.

Antibodies, Monoclonal↗
PubMed1985

Killer cell activity of human monoblastic leukemia cells as detected with a monocyte-specific target cell.

Peripheral blood leukemia cells from patients with acute monoblastic leukemia (AMoL) were tested for killer cell activity against target cells that detected natural killer cell-mediated or monocyte-mediated spontaneous cytotoxicity. The fibrosarcoma cell line Wehi 164, pretreated with actinomycin D to induce susceptibility to lysis, specifically detects the activity of unstimulated human monocytes. In four of six cases of AMoL, high killer cell activity could be measured against this target. In three of these four cases, the killer cell activity could be assigned exclusively to the leukemic clone, based on the high leukocyte counts and the resultant dilution of normal cells, as evidenced by marker and by functional analysis. While leukemic cells with killer cell activity against Wehi 164 contained 34% to 45% cells that were positive for binding of the 63D3 monoclonal antibody, the two leukemic samples without killer cell activity contained only 1% and 12% 63D3-positive cells. Cell sorting of 63D3-positive and -negative cells from two leukemias with killer cell activity demonstrated that the killer cell activity was restricted to the 63D3-positive fraction of AMoL cells. These data demonstrate that monoblastic leukemia cells can be potent killer cells and that killing activity is linked to the 63D3-defined cell surface molecule.

Animals↗
PubMed1985

In vitro differentiation of human melanoma cells analyzed with monoclonal antibodies.

Many monoclonal antibodies (MABs) have been produced against cell surface molecules of melanoma cells, and these reagents might help in the definition of stages of differentiation of the normal and the malignant cells. In an attempt to detect MAB-defined determinants that modulate with differentiation, we treated nonpigmented human melanoma cells with the tumor promotor 12-O-tetradecanoylphorbol-13-acetate (TPA) at 16 nM. Differentiation could be induced in all 4 cell lines, as evidenced by growth retardation, development of projections, and induction of melanin or of premelanosomes in the projections as detected by transmission electron microscopy. Of the 9 MAB-defined cell surface antigens, three were shown to modulate with TPA-induced differentiation, as assessed by fluorescence microscopy and fluorescence-activated cell sorter analysis. Antigens detected by MABs 15.75 and 15.95 decreased in every one of the four cells after TPA induction of differentiation. The proteoglycan defined by 225.28S increased slightly in one, showed no change in another, and decreased in the remaining two. These three MAB-defined molecules thus are linked to differentiation and might help in designing a scheme of differentiation of the melanocyte lineage.

Antibodies, Monoclonal↗
PubMed1984

Possible association between HLA-DR5 and superficial spreading melanoma (SSM).

Previous analyses of possible associations between MHC determinants and cutaneous malignant melanoma (MM) have been inconclusive. We have investigated 98 patients with special emphasis on histologically determined subtypes of MM, and 5 multiple-case families. In addition to HLA-ABC and DR typing, complement allotypes of C2, C4A, C4B, BF were determined. Among the unrelated patients HLA-DR5 and, secondarily, B49 were observed to be associated with superficial spreading (SSM) but not with nodular (NM) or lentigo maligna melanoma (LMM). In families with MM, no definite segregation of the disease according to HLA and complement haplotypes was discernible. Moreover, no coincidence of haplotypes occurred in patients of the different families. HLA region recombinations including B/DR and/or DR/GLO were found in all the families investigated.

Adolescent↗
PubMed1984

[Antibodies against human T-cell leukemia virus type III in acquired immunodeficiency syndrome and persistent lymphadenopathy].

HTLV III and LAV, retroviruses which have recently been described in the United States and France and which seem to be different isolates of the same virus, are closely associated with the acquired immune deficiency syndrome (AIDS) and the lymphadenopathy syndrome (LAS). Sera from male homosexuals from the Federal Republic of Germany with AIDS or LAS were examined for antibodies to HTLV III (anti-HTLV III) by means of the enzyme linked immunoadsorbent assay (ELISA) and by an indirect immunofluorescence assay. 53% of the patients were anti-HTLV III positive as were 20% of symptomless homosexual men.

Acquired Immunodeficiency Syndrome↗
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

Distribution of T-cell subsets as defined by monoclonal antibodies in skin lesions of psoriasis vulgaris.

Cryostat tissue sections from skin lesions of 16 patients suffering from chronic stationary psoriasis vulgaris were assayed for the presence of distinct T-cell subpopulations with monoclonal antibodies. Using two pan-T surface markers (M-T 4-11 and Lyt 3) the total number of infiltrating T-cells was measured. This cell population was further dissected into Leu 3a (helper/inducer) and M-T 8-11 (cytotoxic/suppressor) positive subsets. Percentages of T-cell subpopulations were within the ranges found in healthy peripheral blood and were thus regarded as normal.

Antibodies, Monoclonal↗
PubMed1984

A rapid assay for cytotoxicity of unstimulated human monocytes.

Human peripheral blood mononuclear cells were used as effectors against the Wehi 164 mouse fibrosarcoma cell line grown in suspension culture. In a standard 7-hour 51Cr release assay, specific release usually was below 10%. In contrast, pretreatment of Wehi 164 for 3 hours with dactinomycin (Act D), while leaving the tumor cells intact and viable, resulted in a drastic increase in its susceptibility to lysis, which reached 60% specific release. In terms of lytic units, this reflects up to a fiftyfold enhancement. Cell-separation experiments revealed that the effector cells were plastic-adherent and iron-phagocytic. Adherent cell fractions with 85-98% naphthol AS acetate-esterase (NAS)-positive cells were enriched in cytotoxicity, while nonadherent cells with less than 4% NAS-positive cells were almost devoid of activity. Depletion of phagocytic cells with iron and magnet resulted in a strong reduction of cytotoxicity by 82-95% compared to the cytotoxicity seen in control treated effector cells. In both kinds of analyses, natural killer cell activity showed a reciprocal behavior. The evidence indicates that the cytotoxic effector cells directed against Act D-treated Wehi 164 cells belong to the monocyte lineage. The system described should be useful in analyzing the cytotoxic function of unstimulated monocytes in a short-term assay without prior purification of the effector cells.

Animals↗
PubMed1984

The use of VEP13 monoclonal antibody for definition of natural killer cells: spontaneous killer cells directed against fresh human leukaemia cells carry the VEP13 antigen.

VEP13, an IgM monoclonal antibody (MoAb), produced against human large granular lymphocytes, is able to deplete natural killer (NK) cell activity in complement-dependent lysis. Here we report that VEP13 also reacts with the majority of interferon (IFN) activated NK cells. By contrast cytotoxic activity of unstimulated monocytes and cytotoxic T cells directed against allogeneic lymphocytes were unaffected by VEP13 plus complement treatment. Thus among the major types of cytotoxic cells VEP13 selectively reacts with NK cells and hence can be employed to identify these cells. We therefore used VEP13 in complement-dependent lysis and FACS separation to analyse NK cells involved in enhanced killing of fresh leukaemia cells. Spontaneous cell-mediated lysis of human leukaemia cells was enhanced in two ways: (a) effector cells were pre-treated with beta-IFN and (b) leukaemia cells were pre-treated with a pulse of actinomycin D. In complement-dependent lysis VEP13 removed all NK cell activity of IFN activated PBM against untreated and against ActD pre-treated leukaemia cells. FACS separation of VEP13 positive cells further supported this finding, in that all activity of IFN activated NK cells against actinomycin D pre-treated targets was found in the VEP13 positive fraction. Thus enhanced killing of fresh human leukaemia cells appears to be mediated VEP13 positive NK cells which are distinct from cytotoxic T cells and cytotoxic monocytes.

Antibodies, Monoclonal↗