Klaus Pfizenmaier

Noncytocidal Mechanisms of Action of Tumor Necrosis Factor-α on Human Tumor Cells: Enhancement of HLA Gene Expression Synergistic with Interferon-γ

Abstract In this report, we present evidence that tumor necrosis factor alpha (TNF-α) exerts regulatory activity on the expression of HLA genes in human tumor cell lines at the level of mRNA expression and at a posttranscriptional level. These mechanisms are independent of direct cytotoxic/cytostatic effects, as enhancement of HLA antigen expression was observed in both sensitive cell lines and in cell lines resistant to TNF-mediated growth inhibition. In a priori HLA-negative cells, a strong TNF-α-mediated enhancement of the Interferon gamma (IFN-α) induced expression of HLA genes was revealed by Northern blot and immunofluorescence analysis. A distinct mechanism of TNF-α action is suggested from enhancement of constitutively expressed HLA genes. In this case, TNF-α raised HLA antigen density without apparent enhancement of cytoplasmic mRNA levels. This indicates that TNF-a influences HLA expression also at the level of translation or at a posttranslational level. TNF-a treatment of HLA-negative cells did not by itself result in HLA gene induction, suggesting that TNF-α acts as an enhancer and not as an inducer of HLA gene expression.

Rapid modulation of tumor necrosis factor membrane receptors by activators of protein kinase C

Tumor necrosis factor membrane receptors are rapidly down-regulated upon treatment of activated T lymphocytes with various activators of protein kinase C. Loss of binding-capacity was half maximal after 2 min. incubation in 10 ng/ml of phorbol 12-myristate 13-acetate. A similar modulation could be induced with either the calcium ionophore A 23187 or the protein kinase C activator 1-oleyl-2-acetyl glycerol, whereas 1,2-diolein and dibutyryl cAMP were ineffective. Protein kinase C inhibitor H7 antagonizes the phorbol ester-induced TNF receptor modulation. These data suggest an important role of protein kinase C in the control of TNF responsiveness by regulation of TNF binding-capacity possibly via direct phosphorylation of specific receptor proteins.

Systemische versus lokale Therapie mit rekombinantem Tumor-Nekrose-Faktor-alpha (r-TNF-alpha) bei Patienten mit fortgeschrittenen Tumoren

Im Rahmen von zwei Phase-I-Prufungen wurde rekombinanter Tumor-Nekrose-Faktor-alpha (rTNF-alpha) zur Behandlung von 44 Patienten mit fortgeschrittenen Tumoren unterschiedlichster Histologien eingesetz

Stable expression of a selectable myeloproliferative sarcoma virus in murine T lymphocyte and monocyte cell lines

We have investigated whether a retroviral vector based on the myeloproliferative sarcoma virus (MPSV) can be expressed in murine T cells and macrophages. This vector (neoR MPSV) carries the dominant selection marker for neomycin resistance (neoR) and the mos oncogene. The murine T cell line BW5147 and the monocytic cell line P388D1 were either transfected with neoR MPSV DNA or infected with neoR MPSV virus. From both lines, neoR cell clones could be established by retroviral infection, but not by calcium-phosphate precipitation-mediated DNA transfection. The efficiency of infection could be increased 60- to 200-fold upon cocultivation of target cells with irradiated neoR MPSV virus-producing cells. All neoR clones showed neoR MPSV specific sequences as revealed by dot blot and Southern blot analysis. The integration and expression of neoR MPSV was stable over a period of now more than 4 months, even in the absence of selection for neomycin resistance. Northern blot analysis showed that neoR clones express full length neoR MPSV. Further, clones of both T cell and monocyte origin were capable to produce infectious virus particles as revealed by focus formation on fibroblasts and conversion of neomycin sensitive fibroblasts to a neomycin resistant phenotype.

Rearrangements of T cell receptor genes and expression of high affinity IL-2 receptors in an EBV transformed B cell line

The study is based on the observation of 584 patients (pts) with malignant lymphomas (Morbus Hodgkin 248, Non Hodgkin Lymphoma of favorable histology 2o3, of unfavorable histology 133), who had regular follow ups from 1974-1983. 315 of these pts attained a complete remission( 169, 64,82 respectively). Io8 pts suffered from a relapse (61,22,25). 68% of these pts had symptoms directing to the relapse (62,77,76%). 33% palpated the tumor themselves (36,41,2o%). 2o% showed specific symptoms like local pain or lymphedema (13,13,44%). 15% suffered from general symptoms like B-symptoms (13,13,12%). Regarding the 32% of the pts without symptoms: the relapse was diagnosed by clinical examination in Io%(11, 9,8%). ~fne routinely taken chest x ray showed the relapse in 8% (Io,9,4%), the sonography in 7% (Io,5,4%). in 6% the relapse was discovered by other investigations (7,o,8%). At the time of the relapse the following laboratory findings were striking: 49% of pts with M. H. had a leucocytesis, in 7o% an elevated ESR, in 58% the alpha-2-globulin fraction was increased over Io%. Pts with unfavorable ~L showed in 6o% an elevated ESR and LDH, in 46% the alpha-2-globulin fraction was increased. Our study shows that the history and the clinical examination are the most important parameter recognizing a relapse. Chest x ray and sonography show only in 8 or 7% the relapse. The laboratory findings are less important except the ESR, the LDH and the alpha-2-globulin fraction.