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Biomedical subjects

G Riethmüller

Publications and source records attributed to G Riethmüller.

At least 91 records · Page 5Linked to original sources
PubMed1994

Treatment of endogenous uveitis with anti-CD4 monoclonal antibody: first report.

A patient with endogenous uveitis was treated with a chimeric monoclonal anti-CD4 antibody. This patient with long-standing therapy-refractive uveitis did not benefit immediately from antibody infusions, although the frequency of uveitis relapses was sharply reduced after this therapy. After treatment with the monoclonal antibody, this patient's response to conventional immunosuppression improved. The patient had very low CD4+ T-cell counts before the beginning of antibody therapy. In this case, peripheral T-cell counts slowly increased. Antigen-specific T-cell responses to retinal S-antigen in this patient were significantly elevated only just prior to a clinical relapse. The initially high level of spontaneous T-cell proliferation normalized after antibody infusions.

Adult↗
PubMed1993

Tumor-specific lysis of human renal cell carcinomas by tumor-infiltrating lymphocytes. I. HLA-A2-restricted recognition of autologous and allogeneic tumor lines.

Metastatic renal cell carcinoma (RCC), like melanoma, belongs to the small group of human tumors in which partial or complete remission has been observed in some patients after treatment with various forms of immunotherapy. In contrast to melanoma, CTL showing MHC-restricted lysis of RCC have not been easily found among tumor-infiltrating lymphocytes (TIL). This has led to the suggestion by some that responses to immunotherapy are mediated predominantly by non-MHC-restricted effector cells. We have characterized an MHC-restricted, CD8+ CTL line obtained from an uncloned TIL population of a primary RCC using a low concentration of rIL-2; in fact, these CTL represented a majority of the short-term cultured TIL population. The CTL lysed autologous tumor cells but not normal kidney cells or target cells sensitive to non-MHC-restricted effector cells. In contrast, lymphokine-activated killer (LAK) cells grown in a high concentration of rIL-2 from the patient's PBL lysed autologous tumor and normal kidney cells in addition to several allogeneic tumors. The TIL could be expanded optimally using an autologous tumor line retrovirally transduced with the human cDNA encoding IL-2. TIL were 20-fold more potent than LAK cells in eliminating the IL-2 expressing tumor cells in vitro. The cultured TIL utilized a restricted number of V alpha gene families, suggesting that they may recognize only a limited number of MHC-peptide complexes presented by autologous tumor cells. HLA-A2 was identified as an MHC restriction molecule for presentation of one tumor-derived peptide to these CTL. Only some allogeneic HLA-A2 RCC tumors were lysed. Sequencing of the second and third exons of the HLA-A2 alleles of these cells revealed that both heterogeneity in MHC and peptide availability influenced CTL recognition. These studies demonstrate that some RCC express common antigenic determinants that can be recognized by MHC-restricted CTL and open the possibility of defining the nature of RCC-derived peptides, which, combined with HLA-A2, can generate specific immune responses.

Antibodies, Monoclonal↗
PubMed1993

Genomic organization of the melanoma-associated glycoprotein MUC18: implications for the evolution of the immunoglobulin domains.

The cell surface glycoprotein MUC18, a member of the immunoglobulin superfamily and homologous to several cell adhesion molecules, is associated with tumor progression and the development of metastasis in human malignant melanoma. Immunohistochemical and Northern blot analysis revealed that expression of the antigen is restricted to advanced primary and metastatic melanomas and to cell lines of the neuroectodermal lineage. The genomic sequence encoding the cell surface antigen spans approximately 14 kb and consists of 16 exons. The organization of the gene, which is related to that of the neural cell adhesion molecule N-CAM, shows a structure where each immunoglobulin-related domain is encoded by more than one exon. Sequencing of the putative MUC18 promoter region revealed a G + C-rich promoter lacking conventional TATA and CAAT boxes. Several motifs for binding of transcription factor Sp1 are present in the regulatory region, and only a single transcription start site within a presumed initiator sequence was identified. Sequence elements which might confer melanocyte-specific expression were not detected. Instead, recognition sequences for the transcription factors CREB, AP-2, and c-Myb, as well as CArG-box motifs, were observed. These elements may contribute to the differential regulation of the MUC18 gene in normal and malignant tissues and suggest a role for this putative adhesion molecule in neural crest cells during embryonic development.

Amino Acid Sequence↗
PubMed1993

Differential expression of proliferation-associated molecules in individual micrometastatic carcinoma cells.

BACKGROUND: The development of monoclonal antibodies (MAbs) to cytokeratins, which are integral components of the epithelial cytoskeleton, has made possible immunocytochemical detection of epithelial tumor cells. Importantly, this technique allows the detection of epithelial tumor cells that have metastasized from primary adenocarcinomas to secondary sites such as the bone marrow. PURPOSE: The aim of the study was not only to detect micrometastatic cells in bone marrow, but also to assess the expression of nuclear proliferation markers (Ki-67 and p120) and the erbB2 oncogene (also known as ERBB2) in these cells and, thus, hopefully improve prognostic precision. METHODS: Bone marrow aspirates were obtained from both sides of the upper iliac crest of 532 patients having definitive diagnoses of either breast or gastrointestinal cancer. The presence of micrometastatic epithelial tumor cells in bone marrow was assayed using the MAb cytokeratin 2 (CK2) to cytokeratin component 18 (CK18), in combination with the alkaline phosphatase-anti-alkaline phosphatase immunostaining technique. After primary screening of all marrow samples with MAb CK2, representative subgroups of CK18+ samples were selected for co-labeling with MAbs either to ErbB (n = 16), ErbB2 (n = 121), Ki-67 (n = 33), or p120 (n = 36) protein. An alternative labeling protocol based on the combination of immunogold and immunoenzymatic techniques was utilized to confirm the results derived from immunoenzymatic double staining. RESULTS: In total, single CK18-positive tumor cells were detected in 180 (33.8%) of 532 bone marrow aspirates, with few differences among patients with breast or gastrointestinal cancer in TNM stage M0 (i.e., no distant metastasis). In patients with overt metastasis (stage M1), however, the incidence of metastatic cells in marrow increased to 73.7% in breast cancer, 52.5% in gastric cancer, and 39.0% in colon cancer. Whereas expression of Ki-67 or p120 on micrometastatic cells was observed only in 11 (15.9%) of 69 cancer patients analyzed, ErbB2+/CK18+ cells were found in 48 (67.6%) of 71 breast cancer patients and 14 (28.0%) of 50 patients with gastrointestinal cancer (P = .0001). The incidence of ErbB2+/CK18+ cells was positively correlated with the clinical stage of tumor progression. CONCLUSIONS: The high incidence of ErbB2 expression on micrometastatic breast cancer cells in the bone marrow suggests that these cells might have been positively selected during early stages of metastasis. The majority of these cells appear to be in a dormant state of cell growth. IMPLICATIONS: Although support from clinical follow-up is still needed, this study demonstrates that, beyond the mere presence of micrometastatic cells in bone marrow, useful prognostic information can be obtained by analysis of additional cell growth markers.

Adenocarcinoma↗
PubMed1993

Triple immunofluorescence flow cytometry, using whole blood, of CD4+ and CD8+ lymphocytes expressing CD45RO and CD45RA.

New fluorescent monoclonal antibody-dye conjugates permit three-color immunofluorescence analysis of leukocytes in whole blood using a single laser flow cytometer. The fluorochrome used in this study is a tandem conjugate of phycoerythrin (PE) and Cyan-5, which is excitable at 488 nm with a maximum in the emission spectrum at > 650 nm and it can be used together with PE and fluorescein isothiocyanate (FITC). The directly labelled monoclonal antibodies are incubated with unseparated anticoagulated blood and subsequently erythrocytes are lysed by a standardized automated procedure. The resulting leukocyte suspension can then be analyzed for three different surface markers in an individual sample of 100 microliters blood. When compared simultaneously with single-color analysis triple-color immunofluorescence yielded identical quantitative and qualitative results on various lymphocyte subpopulations. The efficacy of this method was evaluated by analyzing leukocytes of 42 healthy donors for the following markers: CD3, CD4, CD8, CD14, CD16, CD19, CD25, CD38, CD45RO, CD45RA, CD56, CD57, TCR-gamma/delta and HLA-DR. Of special interest was the finding that CD45RA and CD45RO are differently expressed in CD4 and CD8 cells. The reliability and convenience of this three-color analysis will make it possible to do more sophisticated examinations of subpopulations and their relevance in the monitoring of autoimmune diseases, immunodeficiency syndromes including AIDS and malignant disorders such as leukemias.

Adult↗
PubMed1993

Immunocytological detection of bone marrow micrometastasis in operable non-small cell lung cancer.

Present diagnostic techniques do not allow the detection of early metastatic spread of tumor cells, although this spread largely determines the clinical course of patients with small primary cancers. By use of monoclonal antibody CK2 to the epithelial cytokeratin component number 18 (CK18), individual disseminated carcinoma cells present in bone marrow of cancer patients can now be identified (G. Schlimok, I. Funke, B. Holzmann, G. Göttlinger, G. Schmidt, H. Häuser, S. Swierkot, H. H. Warnecke, B. Schneider, H. Koprowski, and G. Riethmüller, Proc. Natl. Acad. Sci. USA, 84: 8672-8676, 1987; F. Lindemann, G. Schlimok, P. Dirschedl, J. Witte, and G. Riethmüller, Lancet, 340: 685-689, 1992). In the present study, we applied this approach to patients with operable non-small cell lung cancer. CK18 was expressed on 84 of 88 (95.5%) primary adenocarcinomas and squamous cell carcinomas. Irrespective of primary tumor histology, single aspirates of iliac bone marrow from 18 of 82 (21.9%) lung cancer patients exhibited between 1 and 531 CK18+ cells/4 x 10(5) nucleated marrow cells. The specificity of our assay is underlined by the small rate of "false-positive" cells being observed in only 2 of 117 (1.7%) marrow samples from control patients with no evidence for an epithelial malignancy at the time of aspiration. Comparison with established risk factors demonstrated positive correlations (P < 0.05) between the size and histological grade of the primary carcinoma and cytokeratin positivity in iliac bone marrow. In contrast, the association with the metastatic involvement of regional lymph nodes was only weak (P = 0.09). Following a median observation period of 13 months, patients who displayed cytokeratin-positive cells in iliac bone marrow at the time of primary surgery relapsed more frequently as compared to patients with a negative marrow finding (66.7 versus 36.6%; P < 0.05). This difference was even more pronounced by comparing the rates of manifest skeleton metastasis observed in both groups (26.7 versus 2.4%; P < 0.005). Finally, colabeling of CK18+ cells in marrow with monoclonal antibodies to proliferation-associated markers, such as the nucleolar antigen p120 or the tyrosine kinase receptor erbB2, exemplified the oncogenic capacity of CK18+ micrometastatic cells. In conclusion, CK18+ cells present in the bone marrow of patients with apparently operable non-small cell lung cancer exhibit the potential to form solid metastases. Therefore, the approach presented here may be used to determine the risk of early relapse in operable non-small cell lung cancer with potential consequences for adjuvant therapy.

Adult↗
PubMed1993

Chimeric CD4 monoclonal antibody cM-T412 as a therapeutic approach to rheumatoid arthritis.

OBJECTIVE: To investigate the effects of chimeric CD4 monoclonal antibody cM-T412 treatment in patients with rheumatoid arthritis (RA). METHODS: Thirty-two RA patients received daily doses of 10, 50, or 100 mg of cM-T412 intravenously for 7 days. RESULTS: There was a sustained decrease in the number of CD4+ T lymphocytes in all patients. Those who received 50 mg and 100 mg of the antibody experienced significant reductions in disease activity. CONCLUSION: Treatment with cM-T412 appears to have a dose-dependent beneficial effect in RA patients. The clinical effects of cM-T412 are independent of the depressed numbers of circulating CD4+ T cells.

Adult↗
PubMed1993

Detection of antineutrophil cytoplasmatic antibodies (ANCA) and their association with other autoantibodies in patients with hepatobiliary disorders.

Sera from 35 out of 655 patients with suspected or confirmed hepatobiliary diseases were positive for anti-neutrophil antibodies with a perinuclear staining pattern (p-ANCA). Nineteen of these sera did not react with myeloperoxidase (MPO), Cathepsin G or Elastase, the three proposed antigens of p-ANCAs. No distinct antigen for these sera could be characterized by western blot techniques with fractionated granulocyte proteins.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1993

Immunocytochemical double staining of cytokeratin and prostate specific antigen in individual prostatic tumour cells.

Early dissemination of malignant cells is the main cause for metastatic relapse in patients with solid tumours. By use of monoclonal antibodies (mAbs) specific for cytokeratins, disseminated individual epithelial tumour cells can now be identified in mesenchymal organs such as bone marrow. Further to characterize such cells in patients with prostate cancer, an immunocytochemical procedure was developed for simultaneous labelling of cytokeratin component no. 18 (CK18) and prostate specific antigen (PSA). In a first step, cells were incubated with mAb ER-PR8 against PSA and secondary gold-conjugated goat anti-mouse antibodies. In a second step, biotinylated mAb CK2 to CK18 was applied as primary antibody and subsequently incubated with complexes of streptavidin-conjugated alkaline phosphatase, which were developed with the Newfuchsin substrate. The binding of gold-labelled antibodies was visualized by silver enhancement. The sensitivity and specificity of the technique was demonstrated on cryostat sections of hyperplastic prostatic tissue, and cytological preparations of LNCaP prostatic tumour cells. Double staining was restricted to cells derived from the secretory epithelium of the prostate. Cross-reactivity between both detection systems was excluded by several controls, including the use of unrelated antibodies of the same isotype and the staining of CK18+/PSA- HT29 colon carcinoma cells. CK18+ cells co-expressing PSA were found in bone marrow aspirates from 5 out of 13 patients with carcinomas of the prostate, a finding that is consistent with the relative fraction of double-positive LNCaP cells. The specificity of CK18 for epithelial tumour cells in bone marrow was supported by negative staining of 12 control aspirates from patients with benign prostatic hypertrophy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1993

Monoclonal antibodies in cancer therapy.

A review of the clinical trials of antibody based cancer therapies reveals that this approach can, in rare cases, induce complete remissions in individual patients with cancer. Since these trials have usually involved patients with large tumor masses, tumor cell inaccessibility is probably a major reason for the prevailing failures. Minimal residual disease, the stage when tumor cells are few and dispersed, should therefore be a more promising target for therapeutic antibodies. This hypothesis is supported by a prospective randomized trial on patients with resected Dukes C colorectal carcinoma that resulted in increased survival and prolonged recurrence-free intervals. Thus, in addition to strategies designed to produce more effective, human-derived reagents, efforts need to be concentrated on directing passive antibody therapy towards the appropriate target.

Antibodies, Monoclonal↗
PubMed1993

Capillary deposition of C4d complement fragment and early renal graft loss.

Clinical outcome of kidney grafts that are affected by the complex syndrome of 'early graft dysfunction' is uncertain and rather unpredictable. In this study, an individual prognosis for dysfunctioning allografts (N = 93) is attempted by the immunohistological assessment of vascular classical complement activation in graft biopsies. Thus, capillary deposition of complement fragment C4d was observed in the majority (N = 51) of early dysfunctioning grafts. In 43 biopsies, abundant deposition of fragment C4d was present in all capillaries, whereas in eight specimens a segmental distribution of capillary C4d was observed. In 42 grafts with early dysfunction no capillary C4d was detectable. Eighteen subsequent graft losses within one year (16 early losses) were recorded in the subgroup with C4d in all capillaries, and three early losses in the group with segmentally distributed C4d. Only four graft losses (3 early losses) were recorded in the C4d-negative group (P = 0.0027; Pearson's chi square test). The resulting one-year graft survival rates (72% for the study group) differed markedly between the subgroups. Grafts with generalized or segmental capillary deposition of C4d had 57% and 63% survival, respectively, contrasted by 90% survival in the C4d-negative group. It is of note, however, that also three of the four grafts that were finally lost within the C4d-negative group, showed distinct capillary deposition of C4d in second biopsies. Vascular deposition of complement fragment C4d therefore represents a clinically relevant factor that contributes to early graft dysfunction. Its assessment is helpful for an individual graft prognosis.

Animals↗
PubMed1993

Distribution of cell adhesion molecules (ICAM-1, VCAM-1, ELAM-1) in renal tissue during allograft rejection.

The tissue distribution of cellular adhesion molecules (CAMs) was studied in specimens from 10 normal human kidneys and in 52 biopsies from kidney allografts with cell-mediated rejection. In addition to the vascular presence of ICAM-1, a common finding in normal kidneys, expression of ICAM-1 on tubular cells was observed in 22 graft biopsies. Compared with normal kidneys, where VCAM-1 was present on Bowman's capsules and few proximal tubular cells, a markedly enhanced expression of VCAM-1 in numerous tubuli (including distal tubular segments) was observed in 51 graft biopsies. In 41 graft specimens VCAM-1 appeared also in variable numbers of peritubular capillaries. Infiltrating leukocytes carrying VCAM-1 were observed in 7 grafts. ELAM-1 could not be found in normal kidneys but was restricted to some peritubular capillaries in 29 grafts. Comparable results were obtained with cultured renal tubular cells when stimulated by TNF-alpha. That the induced appearance of adhesion molecules was in fact related to actual cellular synthesis was demonstrated by Northern blot analysis. Thus, little ICAM-1 specific mRNA of 3.4-kb length could be detected in unstimulated cultured renal tubular cells, but hybridization was markedly increased after stimulation with TNF-alpha. A substantial amount of VCAM-1 specific mRNA of 3.2-kb length was present already in unstimulated renal tubular cells. Likewise, synthesis of VCAM-1 mRNA was enhanced by stimulation with TNF-alpha. TNF-stimulated endothelial cells also showed weak synthesis of VCAM-1 mRNA. The results provide further evidence that constitutive and inducible expression of cell adhesion molecules contributes to the process of allograft rejection.

Antibodies, Monoclonal↗
PubMed1993

Expression of the adhesion molecule ICAM-1 on alveolar macrophages and in serum in extrinsic allergic alveolitis.

ICAM-1 expression was studied on alveolar macrophages (AM) in extrinsic allergic alveolitis (EAA) using immunocytochemistry and cytometry. Compared to control donors, EAA patients had higher percentages of ICAM-1+ AM (75% vs. 30%) and the antigen density was more than sixfold higher (673 vs. 103 channels). Levels of soluble serum ICAM-1 were found increased in EAA patients with an average of 866.2 +/- 300 ng/ml versus 394.8 +/- 110 ng/ml in controls. These data are consistent with the concept that antigen contact upregulates ICAM-1 expression on AM in EAA followed by shedding and an increase in serum sICAM-1.

Adult↗
PubMed1993

Classical pathway of complement activation in mammalian kidneys.

Two monoclonal antibodies (mAb M4d2 and M4d3) specific for the alpha 2-fragment (C4d), and one antibody (mAb M4c3) specific for the gamma-chain of human complement protein C4, have been tested for cross-reactivity against mammalian complement. These mAb have also been found to react with C4 from guinea-pig (mAb M4d2 and M4c3) as well as from cattle, baboon and rhesus monkey (mAb M4d3 and M4c3) in an activation ELISA. Since reactivity of mAb M4d2 and M4c3 included guinea-pig complement, the specific recognition of mammalian C4 could be confirmed with sera from C4-deficient (def') guinea-pigs. mAb M4d2 or M4d3, but not mAb M4c3, stained glomerular deposits within renal tissue sections from pig, cattle and guinea-pig. In the case of mAb M4d2, specificity of that staining could also be demonstrated in kidney specimens from C4-def' guinea-pigs. It can be concluded that, as in humans, the C4d fragment is also present in mammalian glomeruli. Compared with normal guinea-pigs, the C4-def' and C2-def' animals showed markedly increased glomerular deposits of IgM. It appears that glomerular deposition of complement C4d in mammals: (1) indicates activation via the classical pathway; (2) represents a general phenomenon of renal homeostasis; and (3) seems to be involved in the physiological clearance of immune complexes.

Animals↗
PubMed1993

p53 and K-RAS alterations in pancreatic epithelial cell lesions.

We have analysed the expression of p53 at the mRNA level, and extensively at the protein level by immunostaining, Western blotting, and ELISA measurements revealing a p53 increase in 8 out of 14 cell lines established from human pancreatic carcinomas. The mRNA levels closely paralleled the protein levels in most of the cell lines. Overexpression of p53 in tumor cells correlated with mutations in the p53 gene. Immunocytochemistry was also performed with tissue cryosections showing a nuclear p53 staining in 8 out of 12 exocrine, and 2 out of 2 endocrine tumors. In addition, nonmalignant peri-tumoral tissue specimens and cells derived from pancreatic juice of acute pancreatic patients were also positively stained. These findings may suggest functions of p53 in stress situations induced by acute inflammation or tissue regeneration. Genomic mutations in the tumor suppressor gene were associated with point mutations in either codon 12, 13 or 61 in the c-K-RAS oncogene in about two-thirds of cell lines. The frequent activations of a RAS oncogene in combination with mutations of a tumor suppressor gene are likely to contribute to the malignant phenotype of pancreatic adenocarcinomas.

Base Sequence↗