Enhanced tumor cell expression of tumor necrosis factor receptors in head and neck squamous cell carcinoma

BACKGROUND

To determine if tumor necrosis factor (TNF) receptors are upregulated in tumor cells, we measured the distribution and levels of TNF-alpha and TNF-beta, and TNF receptors RI and RII, in head and neck squamous cell carcinoma (HNSCC) tumor specimens and normal control specimens.

METHODS

HNSCC and control tissue specimens were analyzed qualitatively using immunohistochemistry and quantitatively using immunoassays.

RESULTS

Immunohistochemical analysis revealed that TNF-alpha, TNF-beta, TNF RI, and TNF RII antigens were associated predominately with tumor cells in the tissue. Quantitative analysis of TNF factors and receptors in tissue homogenates (mean levels +/- standard error of the mean, in pg/mg of total protein) indicated that: (1) TNF-alpha levels in cancer patients were not statistically different from levels in normal tissues (7.27 +/- 0.91 versus 4.62 +/- 1.33, respectively, P < 0.11); (2) TNF-beta levels in cancer patients were one third of those in normal tissue (5.07 +/- 1.83 versus 16.06 +/- 3.26, respectively, P < 0.01); and (3) both TNF RI and TNF RII levels were consistently elevated two- to four-fold in the cancer tissue when compared to normal tissue levels (1,228.72 +/- 125.67 versus 650.33 +/- 187.70, P < 0.01; and 823.39 +/- 95.90 versus 230.03 +/- 153.01, P < 0.002, respectively).

CONCLUSIONS

In HNSCC, enhanced expression of TNF receptors on the cancer cells occurs and is likely to contribute to the regulation of TNF and its activation of tumor cells within the tumor microenvironment; targeting these receptors in cancer cells may provide a new approach to controlling tumor growth and metastasis.

Homologous ELISA for detection of oligomeric human TNF: properties of the assay

In order to quantify oligomeric human tumor necrosis factor-alpha (TNF), we have developed a sensitive homologous enzyme-linked immunosorbent assay (Hm-ELISA) using the same monoclonal antibody (MoAb) for both solid and liquid phase. Different anti-TNF MoAb have been compared in terms of their efficacy in the Hm-ELISA, affinity, neutralization capacity and epitope specificity. The data suggest, that effectiveness in the Hm-ELISA may represent a novel characteristic of MoAb. Of the MoAbs tested, 5 N was capable of recognizing oligomeric TNF in the Hm-ELISA with a detection limit of 15 pg/ml. Furthermore, using Hm-ELISA against human TNF, interleukin-8 (IL-8) and lymphotoxin, we have demonstrated that these cytokines are oligomeric in physiological solutions, but are converted into monomeric forms in the presence of the non-ionic detergent Tween 20. High salt buffer was employed to abrogate a nonspecific false positive reaction in the Hm-ELISA found in nearly half of the plasma samples obtained from healthy subjects. Finally, a good correlation between the Hm-ELISA and the L929 bioassay was observed for natural and recombinant TNF measured in human plasma.

Immunolocalization of bone-resorptive cytokines in rat pulp and periapical lesions following surgical pulp exposure

The bone-resorptive cytokines interleukin 1 (IL-1) and tumor necrosis factor (TNF) have been implicated in the pathogenesis of many chronic inflammatory diseases, including pulpitis and apical periodontitis.To further elucidate their role in these disorders, we have identified cells that express IL-1 alpha and TNF alpha in infected pulps and in developing rat periapical lesions after surgical pulp exposure. As detected by immunohistochemistry, IL-1 alpha- and TNF alpha-positive cells were present as early as 2 days after pulp exposure in both the pulp and periapical region. The numbers of cytokine-expressing cells increased up to day 4 in the pulp and up to day 30 in the periapex. In contrast, cells expressing IL-1 beta and TNF beta, the homologous forms of these mediators, were not found in pulp or periapical lesions during this period. Cells expressing IL-1 alpha and TNF alpha were identified primarily as macrophages and fibroblasts, with occasional staining of polymorphonuclear leukocytes. Osteoblasts and osteoclasts were also positive, whereas lymphocytes were negative. In general, cytokine-expressing cells were located proximal to abscesses and the root apex. These findings demonstrate that cells that express bone-resorptive cytokines IL-1 alpha and TNF alpha are present immediately after pulp exposure in this model, which supports the hypothesis that these mediators play a key role in pulpal and periapical pathogenesis, including the concomitant bone destruction. They also indicate that both resident connective tissue cells as well as infiltrating cells express bone-resorptive cytokines in response to infection in these lesions.

Interleukin-10 decreases tumor necrosis factor alpha and beta in alloreactions induced by human lung dendritic cells and macrophages

Human lung dendritic cells (DC) are considerably more potent than alveolar macrophages (AM) in inducing allogeneic T-cell proliferation. Tumor necrosis factor (TNF) alpha and beta produced during alloreaction are likely to be major inflammatory cytokines involved. Their concentrations were therefore analyzed during the interaction of AM or DC with allogeneic T cells. TNF alpha and TNF beta levels were respectively three-fold and sevenfold higher in the presence of DC as compared with AM. Cytokines such as interleukin-4 (IL-4), interleukin-10 (IL-10), and transforming growth factor beta (TGF beta) were compared as to their ability to control DC-induced T-cell proliferation as well as TNF alpha or TNF beta production. IL-10 had the unique capacity of reducing both TNF alpha and TNF beta production by 60 +/- 5% (mean +/- SEM) and 63 +/- 12%, respectively, while inhibiting T-cell proliferation by only 32 +/- 23%. IL-4 and TGF beta increased the release of TNF beta by 275 +/- 22% and 95 +/- 32%, respectively, while that of TNF alpha was slightly decreased or unchanged. An additive effect of IL-10 to cyclosporine was found for all three parameters studied. Interaction between CD4 or CD8 with DC was affected similarly by IL-10. Part of this effect could be due to the downregulation of class I and class II major histocompatibility complex expression.(ABSTRACT TRUNCATED AT 250 WORDS)

TNFB gene polymorphism in patients with systemic lupus erythematosus in Korean

OBJECTIVES

To elucidate the gene frequency of TNFB Ncol polymorphism and its association with HLA class II antigen in patients with systemic lupus erythematosus(SLE) in Korea.

METHODS

We investigated the gene frequency of the TNFB alleles using DNA obtained from peripheral mononuclar cells in 141 healthy controls and in 58 patients with SLE. The polymorphisms of TNFB gene (735 bp) were studied by Ncol PCR-RELP. A portion of TNFB gene(735 bp) was amplified by PCR and its products were digested with Ncol restriction enzyme. The digested samples of amplified DNA were analyzed by agarose gel electrophoresis. TNFB*1 and TNFB*2 alleles were identified according to polymorphic fragments on Ncol restriction site in the first intron of the TNFB gene. The generic types of HLA-DRBI were also determined by PCR with sequence specific primers(SSP) using genomic DNA from the same subjects.

RESULTS

The genotypic frequency of TNFB*2 homozygote was significantly increased in patients with SLE compared with controls(RR = 2.36, P = 0.011). The frequency of HLA-DRBI*15 was also significantly increased in patients (RR = 2.27, P = 0.029). However, the increased frequency of TNFB*2 homozygote was apparently increased in nephritis group (RR = 2.79, P = 0.035), whereas the significance of TNFB*2 homozygote was weakend in non-nephritis group.

CONCLUSIONS

Our results suggest that genetic predisposition of TNFB*2 homozygote is another risk factor in Korean SLE, especially in DR2 negative patients. In addition, TNFB*2 homozygote could have a tendency for the development of nephritis in patients with SLE.

Analysis of recombinant human tumor necrosis factor beta by capillary electrophoresis

Capillary electrophoresis was used for the analysis of recombinant human tumor necrosis factor beta (rhTNF-beta). Reproducible separation of the protein could be achieved in Polybrene-coated capillaries. Optimum conditions for separation were achieved with a pH 4.5 sodium acetate buffer. Besides Polybrene-coated capillaries, other commercially available column and column-coating reagents were also examined for the separation of rhTNF-beta. Capillary electrophoresis was found to be a potentially useful method for product analysis and process monitoring in recombinant-DNA technology.

Evaluation of the cytokine response in Kawasaki disease

Intracellular cytokines interleukin 6, tumor necrosis factor (TNF) alpha and TNF-beta were studied in peripheral blood mononuclear cells of patients with Kawasaki disease during the acute, subacute and convalescent stages of the disease utilizing cytokine-specific monoclonal antibodies and indirect immunofluorescence. Intracellular cytokines TNF-alpha and -beta were present only during the acute stage before initiation of therapy and not in the subacute or convalescent phase. Intracellular interleukin 6 was seen in both the acute phase and, in small numbers of patients, in the subacute stage of the illness. Overall 15 of 25 (60%) patients produced at least one intracellular cytokine. In the acute stage both monocyte and lymphocyte cytokines were detected intracellularly, TNF-alpha and TNF-beta in 58% of patients whereas interleukin 6 was seen in only 16%. This study provides evidence to support the involvement of activated mononuclear cells, both T cells and monocytes and their secreted soluble products, cytokines, in the pathogenesis of Kawasaki disease.

Characterization of the apoptotic effects of human tumor necrosis factor: development of highly rapid and specific bioassay for human tumor necrosis factor and lymphotoxin using human target cells

Currently available bioassays for most cytokines require several days and therefore must be performed under sterile conditions. In this report we describe a bioassay for tumor necrosis factor (TNF) and lymphotoxin (LT) that is extremely rapid and specific and does not require sterile conditions. Using tritiated thymidine release, we could conveniently monitor degradation of DNA into small fragments following the incubation of human myelogenous leukemia ML-1a cells with TNF. The assay showed that TNF-dependent DNA fragmentation was potentiated by cycloheximide and occurred within 90 min. Treatment of cells to TNF lead to apoptosis as indicated by thymidine release, DNA laddering on agarose gels and morphological alterations. Under these conditions, plasma membrane were not damaged as indicated by lack of chromium release. This effect was linear with TNF concentration. This assay had high throughput, did not require sterile conditions, could be carried out in the absence of serum, and was sensitive only to TNF and LT and not to interferon (IFN)-alpha, IFN-beta, IFN-gamma, transforming growth factor beta, interleukin-4, leukemia inhibitory factor and granulocyte-monocyte colony stimulating factor; all cytokines known to inhibit different cell types. Besides detection of TNF in biological fluids, this assay may prove useful for the identification of novel inhibitors of TNF action.

Relationship between alpha 1-antitrypsin inactivation and tumor necrosis factor alpha concentration in the synovial fluid of patients with rheumatoid arthritis

OBJECTIVE

To examine the relationship between alpha 1-antitrypsin (alpha 1AT) specific activity and tumor necrosis factor alpha (TNF alpha) concentration in synovial fluid from 48 patients with rheumatoid arthritis.

METHODS

The specific activity of alpha 1AT was calculated from the measurement of alpha 1AT concentration (by rocket immunoelectrophoresis) and elastase inhibitory capacity. TNF alpha was detected by enzyme-linked immunosorbent assay.

RESULTS

TNF alpha concentrations correlated with the extent of alpha 1AT inactivation.

CONCLUSION

Our findings are consistent with a role of elastase in TNF alpha release within the inflamed joint.

Cytokine gene profile in circulating blood mononuclear cells from patients with systemic lupus erythematosus: increased interleukin-2 but not interleukin-4 mRNA

Cytokines are important in developmental and effector pathways of lymphocyte function. Our objective was to elucidate the profile of cytokines produced by circulating mononuclear cells from patients with systemic lupus erythematosus as estimated from studies of cytokine-gene activation. cDNA prepared by reverse transcription of lymphocyte mRNA was amplified using the polymerase chain reaction and normalized on the basis of beta-actin gene expression. Of 10 cytokines investigated in 16 individuals, differences between SLE and controls were found in only three. IL-2 transcripts were detected in four of six cases of subjects hospitalized for active SLE, but in only one of seven healthy controls, and none of three cases with pulmonary tuberculosis. By contrast, IL-4 transcripts were decreased compared with healthy controls and patients with tuberculosis. Also, TGF beta transcripts appeared to be decreased in SLE. All individuals studied regularly demonstrated high levels of transcripts for IL-1 beta, IL-6 and TNF alpha and transcripts for IFN gamma, TNF beta, IL-5 and IL-10 were variably expressed. In a second group of six SLE patients with less active disease, there was also a decrease in IL-4 expression compared with six healthy controls. Moreover, assays performed on sera from patients with active SLE revealed that IL-4 levels were not increased. Although in mice this cytokine has a well documented role in supporting antibody production, this study provides no evidence that IL-4 is involved in the B cell hyperactivity characteristic of human SLE.

Induction of cytosolic phospholipase A2 in human leukocytes by lipopolysaccharide

Stimulation of peripheral blood leukocytes with lipopolysaccharide results in the synthesis of inflammatory cytokines including interleukin-1 beta, interleukin-6, tumor necrosis factor-alpha and prostaglandin E2 correlating with an increase in phospholipase A2 activity. Mammalian cells contain several phospholipase A2 isoforms including the 14-kDa secretory isoform and the more recently described high-molecular-mass cytosolic isoform. It is commonly believed that during inflammatory responses secretory phospholipase A2 becomes activated. However, we could not detect secretory phospholipase A2 nor its corresponding mRNA after lipopolysaccharide-induced activation. By contrast, we found increased mRNA levels for cytosolic phospholipase A2 following activation of peripheral blood leukocytes when levels were compared to non-stimulated controls. Our results demonstrate that cytosolic phospholipase A2, rather than the secretory isoform may be the mediator of the lipopolysaccharide-induced inflammatory cascade in human peripheral blood leukocytes.

Cellular localization of inflammatory cytokines in human glomerulonephritis

We evaluated the expression of inflammatory cytokines in renal tissues obtained from 45 patients with several types of glomerulonephritis. Immunofluorescence studies with specific antibodies to interleukin (IL)-1 alpha, IL-1 beta, IL-6, tumour necrosis factor (TNF)-alpha, and TNF-beta showed intense cytoplasmic staining in the glomeruli and interstitium. Cells positive for these cytokines were found frequently in tissue from patients with lupus nephritis (WHO Class IV) and membranoproliferative glomerulonephritis, and, to a lesser extent, in tissue from patients with mesangial proliferative glomerulonephritis, Henoch-Schönlein purpura nephritis, and minimal change nephrotic syndrome. Most of these cells were dual-stained with a monoclonal antibody to monocytes-macrophages. In situ hybridization for cytokine mRNA, combined with immunoperoxidase staining for monocytes-macrophages, detected IL-1 alpha, IL-6, and TNF-alpha mRNA in monocytes-macrophages infiltrating the glomeruli and interstitium. Occasionally, there was weak or moderate immunostaining for IL-1 alpha, IL-6, and TNF-alpha in the glomerular mesangial and epithelial cells, but in situ hybridization signals were rarely found in these loci. These findings suggest that infiltrating monocytes-macrophages, rather than resident glomerular cells, are the major source of inflammatory cytokines in human glomerulonephritis.

Local synthesis of both macrophage and T cell cytokines by synovial fluid cells from children with juvenile rheumatoid arthritis

The production of tumour necrosis factor-alpha (TNF-alpha), TNF-beta and IL-6 in synovial fluid was studied in 50 samples of synovial fluid from 44 children with juvenile rheumatoid arthritis (JRA) by identifying cytokine production at a single-cell level. Post Ficoll-separated synovial fluid mononuclear cells were permeabilized and then intracellular TNF-alpha, TNF-beta and IL-6 protein production was examined using indirect immunofluorescence and murine anti-cytokine MoAbs. All three cytokines were measured in 37 of the 50 samples. In 25 of the 37 samples there was complete concordance; all three cytokines were present in six and absent in 19 samples. At least one cytokine was present in 27/50 (54%) of synovial fluid samples. Overall, TNF-alpha was detected in 22/49 (45%) samples, TNF-beta in 15/41 (37%) and IL-6 in 16/45 (36%) samples. Five patients had serial arthrocentesis, and in these samples there were two patients who had initially positive cytokine production, which on subsequent measurement was negative; in the other three patients there was no change from the previous cytokine production. We provide evidence that synovial fluid mononuclear cells produce monocyte and T cell cytokines in JRA. These findings suggest a role for both T cell and macrophage products in the pathogenesis of JRA, and the potential for modulation of cytokine production as a target for therapeutic intervention.

Brain vessels near muscle autografts are sites for entry of isogeneic macrophages into brain

An autograft of skeletal muscle on rat dorsal medulla is a permanent opening in the blood-brain barrier to solutes. Is the graft also a site for the entry of exogenous, isogeneic leukocytes? Five weeks after inserting the graft, peritoneal macrophages (M phi) from inbred Fischer rats were activated by phorbol myristate acetate, labeled with a fluorescent dye, and infused as a bolus of about 2 x 10(6) cells into the axillary artery of Fischer hosts. The cells circulated for 2 h. The brains were then fixed, frozen, and sectioned. Only when M phi had been activated and a muscle autograft inserted did appreciable numbers of M phi enter the medulla. Nonactivated M phi invaded the grafts but very few entered the brain at 2 h. In rats with gel foam grafts, only a few activated M phi invaded gel and brain. Before entering tissues, M phi must adhere to the lumenal face of vessels. Cell adhesion molecules, e.g., I-CAM-1 and its ligand adhesion molecule, leukocyte function antigen (LFA-1), are known to mediate adhesion. I-CAM-1, detected immunohistochemically, increased in graft vessels and in nearby brain vessels. The rise may have been mediated by cytokines, interleukin-6, and tumor necrosis factor-beta, found in the grafts. LFA-1, however, assayed by fluorescence-activated cell sorting, was on both activated and nonactivated, exogenous M phi. Thus, M phi-endothelial attachment may have involved other adhesion molecules, e.g., selectins. The autograft also induced major histocompatibility complex class I on microglia and classes I and II on brain vessels near the graft. These vessels, by expressing adhesion molecules, are entry routes into brain for activated, isogeneic leukocytes that can then migrate for a limited distance of 1-2 mm in an otherwise intact brain.

Expression of perforin and membrane-bound lymphotoxin (tumor necrosis factor-beta) in virus-specific CD4+ human cytotoxic T-cell clones

In an attempt to clarify the mechanisms of cytotoxicity mediated by CD4+ cytotoxic T lymphocytes (CTL), the expression of perforin and membrane-bound lymphotoxin (LT) (tumor necrosis factor-beta) in herpes simplex virus (HSV)-specific CD4+ human cytotoxic and noncytotoxic T-cell clones was examined. Three HSV-specific CD4+ human CTL clones that showed HLA-DR-restricted cytotoxicity and proliferative response were established. The cytotoxicity of these clones in 5-hour 51Cr release assays was found to be mediated by the directional target cell lysis and not by the release of cytotoxic soluble factors, ie, "innocent bystander" killing. Northern blot analysis showed that messenger RNAs for perforin and LT, which were both considered to be important mediators for cytotoxicity of CD8+ CTL and natural killer cells, were abundantly expressed in HSV-specific CD4+ CTL clones. Expression of perforin in the cytoplasm of CD4+ CTL clones was also detected by immunohistochemical staining using a monoclonal antibody against perforin. In addition, LT bound to the cell surface of CD4+ CTL clones was detected by flow cytometry. In contrast, little or no expression of perforin and LT was detected in three HSV-specific CD4+ noncytotoxic T-cell clones. Although the cytotoxicity mediated by lymphokine-activated killer cells was partly inhibited by addition of anti-LT antibody, it did not show any effect on the cytotoxicity of HSV-specific CD4+ CTL clones. In addition, it was found that cytotoxicity mediated by these CD4+ CTL clones was Ca2(+)-dependent. These data thus suggest that perforin and membrane-bound LT are both expressed in HSV-specific CD4+ CTL, although perforin might be the more important mediator in short-term culture.

TNF production and hypertrophic scarring

The percentage of TNF alpha- and beta-positive cells was analyzed in hypertrophic scar (N = 13), normotrophic scar (N = 7), and normal skin (N = 6) biopsies using monoclonal antibodies and immunoperoxidase staining of cryostat tissue sections. Samples were first characterized for infiltrating cells. In hypertrophic samples there was a significant increase in activated infiltrating cells, capable of producing TNF beta and IL-1 beta. In contrast, the percentage of TNF alpha-positive cells was significantly lower than that detected in normotrophic scars. In fact, in hypertrophic scar samples a positive staining with anti-TNF alpha mAb was restricted to 8% of tissue-infiltrating cells compared to 35.4% of the cells present in normotrophic scars; 12% of infiltrating cells were stained in normal skin sections. These results suggest that TNF alpha may be important for normal wound healing and that hypertrophic scarring might be partially a consequence of a low amount of TNF alpha.

Lymphotoxin is an autocrine growth factor for Epstein-Barr virus-infected B cell lines

Because human lymphotoxin (LT) was originally isolated from a lymphoblastoid cell line, we investigated the role of this molecule in three newly established Epstein-Barr virus (EBV)-infected human B cell lines. These lines were derived from acute lymphoblastic leukemia (Z-6), myelodysplastic syndrome (Z-43), and acute myelogenous leukemia (Z-55) patients who had a prior EBV infection. Each lymphoblastoid cell line had a karyotype that was different from that of the original parent leukemic cells, and all expressed B cell, but not T cell or myeloid surface markers. In all three lines, rearranged immunoglobulin heavy chain joining region (JH) bands were found, and the presence of EBV DNA was confirmed by Southern blotting. Z-6, Z-43, and Z-55 cell lines constitutively produced 192, 48, and 78 U/ml LT, respectively, as assessed by a cytotoxicity assay and antibody neutralization. Levels of tumor necrosis factor (TNF) were undetectable. Scatchard analysis revealed that all the cell lines expressed high-affinity TNF/LT receptors with receptor densities of 4197, 1258, and 1209 sites/cell on Z-6, Z-43, and Z-55, respectively. Furthermore, labeled TNF binding could be reversed by both unlabeled TNF, as well as by LT. Studies with p60 and p80 receptor-specific antibodies revealed that the three lines expressed primarily the p80 form of the TNF receptor. When studied in a clonogenic assay, exogenous LT stimulated proliferation of all three cell lines in a dose-dependent fashion at concentrations ranging from 25 to 500 U/ml. Similar results were obtained with [3H]TdR incorporation. Monoclonal anti-LT neutralizing antibodies at concentrations of 25-500 U/ml inhibited cellular multiplication in a dose-dependent manner. It is interesting that in spite of a common receptor, TNF (1,000 U/ml) had no direct effect on Z-55 cell growth, whereas it partially reversed the stimulatory effect of exogenous LT. In addition, TNF inhibited Z-6 and Z-43 cell proliferation, and its suppressive effect was reversed by exogenous LT. Both p80 and p60 forms of soluble TNF receptors suppressed the lymphoblastoid cell line proliferation and their inhibitory effect was partially reversed by LT. Our data suggest that (a) LT is an autocrine growth factor for EBV-transformed lymphoblastoid B cell lines; and (b) anti-LT antibodies, soluble TNF/LT receptors, and TNF itself can suppress the growth of lymphoblastoid cells, probably by modulating or competing with LT.(ABSTRACT TRUNCATED AT 400 WORDS)

Inter-relationships between pterins and cytokines produced during allogeneic immune reactions and possible use as early markers of immune activation

The pterins neopterin and xanthopterin have been measured together with the cytokines IFN-gamma, TNF-alpha and TNF-beta in the supernatants of 20 allogeneic mixed lymphocyte reactions. We have calculated rank correlation coefficients between these analytes and the immune response. Our findings confirm that neopterin is a sensitive early marker of immune activation and show that another pterin, xanthopterin could be used likewise. Cytokine production was also proportional to immune activation but none could be used consistently as early markers of immune activation.

Correlation between killing activity towards the murine L929 cell line and expression of membrane-associated lymphotoxin-related molecule of human lymphokine-activated killer cells

Human lymphokine-activated killer (LAK) cells expressed a membrane-associated lymphotoxin-related molecule (mLT) which was detected by flow cytometric analysis with anti-lymphotoxin antibody. Upon removal of exogenous interleukin-2 from LAK cell culture medium and another 24 h cultivation, the expression of mLT was decreased. Corresponding to the decrease of mLT expression, the killing activity of LAK cells towards L929 cells was remarkably reduced and killing of MIA PaCa-2 and U937 cells was moderately reduced, whereas killing of Daudi and K562 cells was fully restored. The supernatant of mLT-expressing LAK cells had no cytotoxic activity towards L929 cells in the absence of actinomycin D. Moreover, not only the killing of L929 cells but also that of human tumor cell lines (MIA PaCa-2, U937) by mLT-expressing LAK cells was partially inhibited in the presence of anti-lymphotoxin antibody. These results suggest an involvement of mLT in the killing of some tumor target cells by LAK cells.

Tumor necrosis factor-beta and hypercalcemia

Hypercalcemia in hematological malignancy is frequently encountered in lymphoid malignancies such as adult T-cell leukemia (ATL) and multiple myeloma and is difficult to manage. As a causative agent of hypercalcemia in ATL, tumor necrosis factor-beta (TNF-beta), previously known as lymphotoxin, has been carefully studied and reviewed here. Bone resorption studies showed the presence of activity in culture supernatants of HTLV-I infected cells. Enzyme linked immunosorbent assays (ELISA) for TNF-beta detected elevated TNF-beta in the sera of ATL patients with hypercalcemia. Immunostaining by monoclonal anti-TNF-beta antibody demonstrated the presence of TNF-beta in both HTLV-I infected cell lines and freshly isolated ATL cells. Furthermore biological TNF-beta activity assay including inhibition of anti-TNF-beta antibody confirmed the conventional documentation of TNF-beta activity in the sera and culture supernatants of HTLV-I infected cell lines. These studies showed that the TNF-beta secreted from ATL cells might be one of the factors contributing to the hypercalcemia in patients with ATL functioning as an osteoclast activating factor (OAF).

Expression of transforming growth factor type beta on human epidermal dendritic cells

Our study demonstrates that epidermal Langerhans cells (LC) of healthy human skin produce Transforming growth factor-beta (TGF-beta). This multipotent mediator might keep the immunocompetent LC in an "immature" stage, in which they are able to capture and process antigen. Development to potent antigen-presenting cells would become possible after migration from the epidermal network to the draining lymph node to stimulate (auto-)reactive T-cell clones.

Regulation of lymphokine-activated killer cell induction by human recombinant IL-1 receptor antagonist. Obligate paracrine pathway of IL-1 during lymphokine-activated killer cell induction

IL-2-stimulated human lymphocytes, referred to as lymphokine-activated killer (LAK) cells, can develop a broad range of lytic activity against fresh tumor cells and cultured tumor cell lines. IL-1, a pleiotropic cytokine shown to synergize with IL-2 on LAK induction, is endogenously synthesized and secreted by LAK cells. Immunoblot analysis demonstrated that IL-2-stimulated PBL produced the 31- to 34-kDa pro-molecules of IL-1 within 24 h and maintained their expression for at least 96 h. The role of secreted IL-1 has been examined using rIL-1R antagonist (IL-1ra). The addition of IL-1ra to LAK activation culture resulted in dose-dependent inhibited lytic activity, which was more apparent in LAK cells cultured with higher doses of IL-2. However, IL-1ra had no effect on proliferative responses elicited in LAK cells by IL-2. Moreover, when IL-1 binding was blocked by IL-1ra, the expression of the IL-2R p55 subunit was reduced compared with control LAK cells. The effect of IL-1 binding blockade on expression of other cytokine mRNA was further examined by polymerase chain reaction analysis, and, specifically, inhibition of both TNF-alpha and TNF-beta mRNA expression by IL-1ra was observed in PBL stimulated with IL-2. The reduced biologic activity of TNF in culture supernatants correlated well with the inhibition of mRNA expression. These findings suggest that autocrine/paracrine IL-1 is involved in the initial generation of LAK activity and, in particular, that TNF expression could be induced via an IL-1 autocrine pathway.

Cytokines in proliferative vitreoretinopathy

This study determined the presence of interleukin 1 (IL-1), interleukin 6 (IL-6), tumour necrosis factor alpha (TNF alpha), tumour necrosis factor beta (TNF beta), interferon gamma (IFN gamma), transforming growth factor beta 2 (TGF beta 2) and fibroblast proliferation activity (FPA) in vitreous aspirates from eyes undergoing vitrectomy for the treatment of retinal detachment complicated by proliferative vitreoretinopathy (PVR) or uncomplicated retinal detachment (RD). Cadaveric vitreous from normal subjects were used as controls. The results showed that IL-1 and IL-6 predominated in vitreous from eyes with PVR or RD, and that concentrations of IL-6 greater than 20 pg/ml were more frequently found in PVR than in RD (p = 0.031) or control specimens (p = 0.006). Low levels of TNF alpha were observed in 4/18 eyes with PVR, 1/15 eyes with RD and 1/15 control vitreous, and small concentrations of TNF alpha were seen in 3/18 eyes with PVR, 1/15 eyes with RD and 2/15 control vitreous. IFN gamma was detected in 12/18 eyes with PVR, but only in 5/15 eyes with RD (p = 0.048) and 6/15 control specimens. TGF beta 2 was present in all vitreous samples at concentrations ranging from 100 to 4,500 pg/ml with no significant differences among the three groups. Control vitreous possessed the greatest FPA when compared with vitreous from eyes with PVR (p = 0.031) or RD (p = 0.048). These observations provide further evidence that cytokine-mediated pathways of inflammation are involved in the pathogenesis of PVR and point to the possible involvement of IL-1, IL-6 and IFN gamma in cellular interactions leading to chronicity.

A role for gamma interferon, tumor necrosis factors, and soluble T-cell receptors in the depressed blastogenic response of spleen cells of Mycobacterium lepraemurium-infected mice

Spleen cells of Mycobacterium lepraemurium-infected mice were cultured on petri dishes coated with mycobacterial antigens, and antigen-reactive cells were isolated. Upon incubation in mitogen- or antigen-free culture medium, these cells released mediators capable of depressing the in vitro proliferative response of normal splenocytes to specific antigen and to concanavalin A and lipopolysaccharide. One of these mediators was identified with gamma interferon (IFN-gamma), mainly on the basis that treatment of supernatants with monoclonal anti-IFN-gamma antibodies markedly reduced the suppressive activity contained therein. Detectable levels of tumor necrosis factor alpha (TNF-alpha) and TNF-beta were present in spleen cell culture supernatants of infected mice. Moreover, low doses of recombinant TNF-alpha and TNF-beta were found to potentiate the suppressive activity of exogenous IFN-gamma. Soluble T-cell receptors beta were also detected in the culture supernatants. The elimination of these molecules with monoclonal anti-T-cell receptor beta (F23.1) antibodies immobilized on a plastic surface partially reversed the depression of the response to mycobacterial antigen but did not affect the response to mitogens. These results revealed the complex nature of suppressor mediators that are produced by mycobacterial antigen-reactive cells and that regulate the in vitro proliferative response.