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Expression of human lymphotoxin in Namalwa KJM-1 cells adapted to serum-free medium.

A Namalwa cell line, KJM-1, which was adapted to serum-free medium is thought to be a good host cell line for recombinant DNA technology. We previously reported the expression of human beta-interferon (beta-IFN) in Namalwa KJM-1 (Miyaji, 1989a). The utility of Namalwa KJM-1 for expression of foreign genes was further examined. As a target gene to be expressed, human lymphotoxin (hLT) cDNA was used. It was engineered for expression in Namalwa KJM-1 using a simian virus 40 (SV40)-based expression vector pAGE107 (Miyaji, 1989a). It contains all components necessary for the expression of cDNA in mammalian cells. The expression vector was introduced into Namalwa KJM-1 by electroporation. Among the transformants, clone 7 was further examined for the expression of hLT in serum-free medium. The production level of hLT was augmented with the increase of the cell density. Thus it was further indicated that Namalwa KJM-1 is useful for production of foreign gene products.

Cell Line↗

Control of the carcinogenic potential of 99mTechnetium by the immunologic hormone lymphotoxin.

Immunologic prevention of the carcinogenicity of the diagnostic gamma-emitting radionuclide 99mTechnetium (99mTc) by lymphotoxin was evaluated using an in vivo-in vitro assay of carcinogenesis. Pregnant Syrian golden hamsters received 125-2,300 microCi 99mTc/kg body weight by injection, and 7 days later colonies of morphologically transformed cells were quantitated in vitro. The transformation frequency increased directly with the radionuclide concentration, and cells derived from transformed colonies produced tumors in athymic nude mice. The total absorbed 99mTc dose was 0.20 rad following injection of 250 microCi 99mTc/kg hamster body weight; this compares with an exposure of 0.13 rad following injection of 143 microCi 99mTc/kg body weight in humans. Intravenous injection of purified hamster lymphotoxin immediately after 99mTc caused a dose-dependent reduction in the transformation frequency. Transformation was essentially completely prevented (97%) by injection of 8,000 U of lymphotoxin. Thus, the immune system, through the action of lymphotoxin, has the potential to prevent carcinogenesis induced by gamma-radiation from 99mTc. This emphasizes the importance of considering the recipient's immune and other homeostatic mechanisms as part of a complete diagnostic or therapeutic gamma-radiation regimen.

Animals↗

Mechanism of natural delayed-type hypersensitivity reactions to tumor cells in nonimmunized syngeneic guinea pigs.

Nonimmunized 2/N guinea pigs respond to the presence of chemical carcinogen-transformed syngeneic tumorigenic cells with a sustained (delayed-hypersensitivity-type) 4-day intradermal induration consisting of predominantly polymorphonuclear leukocytes on day 1 and mononuclear cells by day 4, which is independent of the presence of tumor-specific antigens on the tumorigenic cells. Chemical carcinogen-induced morphologically transformed but nontumorigenic cells also induce a polymorphonuclear response by day 1, but neither induration nor a mononuclear response is present on day 4, demonstrating the specificity of the 4-day sustained indurative response for tumorigenic cells. Induration and cellular infiltrates are unaltered if tumor cells are treated prior to injection with the cytostatic lymphokine lymphotoxin or with x-irradiation to inhibit cell proliferation. The intradermal polymorphonuclear leukocyte host response on day 1, but not the mononuclear response on day 4, is also induced by mitomycin C-treated cells or a cytokine culture medium from the cells. No response is present on day 1 or day 4 when cell membranes or lyophilized cells are injected. Thus natural delayed-hypersensitivity-type skin reactivity is a mononuclear leukocyte response specifically directed against intact and metabolically active but not necessarily proliferating tumor cells.

Animals↗

A human macrophage hybridoma producing a cytotoxic factor distinct from TNF, LT, and IL-1.

A stable human macrophage hybridoma was established by somatic cell fusion between human peripheral blood monocyte-derived macrophages and an 8-azaguanine resistant clone of a human histiocytic lymphoma cell line U-937 (clone U-937-F9). The hybrid cell line (F9P) exhibited typical macrophage-like morphology and had 30 more chromosomes than U-937-F9 cells. Its macrophage characteristics were confirmed by the manifestation of intracellular nonspecific esterase, the detection of Mo-2 and LEU-M3 antigens on the cell surface, and the demonstration of phagocytic activity. Furthermore, when stimulated with lipopolysaccharide (LPS), this cell line could secrete a considerable amount of a cytotoxic factor (CTF). Distinct from the hybrid cell line, the parental U-937-F9 cells expressed neither Mo-2 nor LEU-M3 antigens on the cell surface, did not show phagocytic activity, and their culture supernatants did not show cytotoxic activity even after LPS stimulation. The activity of CTF in the culture supernatant of the LPS-stimulated hybrid cells could not be neutralized with anti-tumor necrosis factor, anti-interleukin-1, or anti-lymphotoxin antibodies. The CTF had a relative molecular mass of 45-60 x 10(3) daltons as determined by gel filtration on a column of Superose 12, and an isoelectric point of 5.1. The cytotoxic activity was also induced when the hybrid cells were stimulated with the concentrated supernatants of a human T-cell hybridoma containing macrophage activating factor for cytotoxicity or with LP3 tumor cells which were used as target cells.

Antibodies↗

Enhancement of human immunodeficiency virus production by natural lymphotoxin.

The effect of natural lymphotoxin (n-LT) on CD4+ MOLT-4 cells and those cells producing human immunodeficiency virus (HIV), MOLT-4/HIVHTLV-IIIB cells, was studied. Four days after treatment with n-LT, a significant cytotoxic/cytostatic effect was observed predominantly on MOLT-4/HIVHTLV-IIIB cells. Furthermore, with regard to the production of HIV, an almost 3- to 5-fold increase of viral particles was observed in MOLT-4/HIVHTLV-IIIB cells 6 h after treatment with n-LT. These data indicate the possibility that this cytotoxic factor is one of the responsible molecules in the pathogenesis of the acquired immunodeficiency syndrome (AIDS).

Antibodies, Monoclonal↗

Association of polymorphisms in the HLA-B region with extended haplotypes.

Genomic probes from the HLA-B region of the major histocompatibility complex (MHC) were used to study the association of restriction fragment length polymorphisms (RFLPs) with various MHC alleles, complotypes, and extended haplotypes. The two DNA probes, M20A and R5A, were derived from previously cloned cosmids and are located 38 and 110 kilobases (kb) centromeric to HLA-B, respectively. Five different RFLP variants occurring in five different haplotypic combinations were detected within a panel of 40 homozygous-typing cells and cells from 21 families using Bst EII. In two informative families with HLA-B/DR recombinations the inheritance of the RFLP variants was consistent with their mapping between HLA-B and complotypes. The R5A/M20A haplotypic pattern 6.5 kb/3.0 kb (A) had a normal Caucasian frequency of approximately 0.43 and was found in all independent examples of the extended haplotypes [HLA-B8,SC01,DR3], [HLA-B18,F1C30,DR3], [HLA-Bw62,SC33,DR4], [HLA-B44,SC30,DR4], and [HLA-Bw47,FC91,0,DR7]. The patterns 6.9 kb/3.0 kb (B), 6.5 kb/4.7 kb (C), 1.45 kb/3.0 kb (D), and 6.9 kb/4.7 kb (E) had normal Caucasian frequencies of approximately 0.23, 0.15, 0.15, and 0.04 and were found on all independent examples of [HLA-B38,SC21,DR4], [HLA-Bw57,SC61,DR7], [HLA-B7,SC31,DR2], and [HLA-B44,FC31,DR7], respectively. Individual complotypes or HLA-B alleles which were markers of extended haplotypes showed variable associations. For example, HLA-B7 and the complotype SC31 were associated with all R5A/M20A RFLP haplotypes except haplotype E, although [HLA-B7,SC31,DR7] was associated exclusively with haplotype D. HLA-B27, not known to be part of an extended haplotype, was surprisingly exclusively associated with the 6.5 kb/4.7 kb or C haplotypic pattern in all five instances tested. These findings support the concept of regional conservation of DNA on independent examples of extended haplotypes. The results also further characterize these haplotypes.

Alleles↗

Haplotypic polymorphisms of the TNFB gene.

The TNFB genes from two major histocompatibility complex (MHC) ancestral haplotypes have been compared. The genes carried by the ancestral haplotypes 8.1 (A1,B8,BfS,C4AQ0, C4B1,DR3) and 57.1 (A1, B57. BfS, C4A6, C4B1, DR7) were cloned and sequenced to determine the degree of polymorphism. In this report we show that the respective TNF genes are allelic and have unique nucleotide sequences. The data demonstrate the presence of three nucleotide differences between the TNFB alleles of 8.1 and 57.1. Two of the differences occur in untranslated regions of the gene but the third nucleotide change results in an amino acid difference in the mature TNFB protein. These polymorphisms may have implications with respect to differential regulation in disease- and nondisease-associated haplotypes.

Alleles↗

Activation of human T-lymphocytes. A kinetic and stereological study.

Stereological data of phytohaemagglutinin (PHA)-activated human T-lymphocytes were recorded at intervals (12 to 72 h) together with biochemical (isotope-uptake, lymphotoxin-release) and morphological measurements. About 98% of the cells were activated 12 h after PHA-stimulation. The activation phase lasted less than 48 h, i.e., cells entering the activation phase within 12 h were at their activation maximum by 48 h. The activated cell increased in size. The nuclear/cytoplasmic-ratio decreased. Most of the cytoplasmic organelles developed in phase with the increase of cytoplasmic volume. After 48 h, mitotic figures were frequently seen. Due to the increasing number of secondary, activated daughter cells, parameters of most cytoplasmic components declined between 48 and 72 h. Structural changes in the nucleus preceded the 3H-leucine uptake, which had not reached its maximum after 72 h of incubation. The 3H-leucine uptake started as early as 12 h after culture initiation, and its increase was proportional to the increasing polyribosome density. No maximum uptake was reached up to 72 h, but the development of structural components related to this uptake was at its maximum at the end of the activation phase (48 h). The formation of bound ribosomes occurred subsequent to the enlargement of the surface of the rough endoplasmic reticulum. Initial polysome formation occurred at the expense of existing free ribosomes.

Adult↗

Effects of interleukin-1, tumor necrosis factor -beta, and forskolin on tissue plasminogen activator activity in human osteoblastic osteosarcoma cells.

The effects of interleukin-1 (IL-1), forskolin, and tumor necrosis factor beta (TNF-beta) on tissue plasminogen activator (t-PA) activity were studied in the human osteoblastic osteosarcoma cell line, G292. t-PA activity was measured in the cell media using the chromogenic substrate, S-2251. After a 24 hour incubation period, IL-1 increased t-PA in a dose-dependent manner. The effect of IL-1 at 10.0 U/ml was partially inhibited in the presence of indomethacin. Forskolin (1.0 microM) increased t-PA activity after 24 hours with the effects of combined treatment of IL-1 (1.0 U/ml, 10.0 U/ml) and forskolin being apparently additive in nature. TNF-beta (10(-8)-10(-7)M) also produced increased t-PA activity in the cell media after a 24 hour incubation period. These results suggest that the cytokines, IL-1 and TNF-beta, can increase t-PA activity in G292 cells and that there is both a cAMP-dependent as well as a cAMP-independent pathway involved in the regulation of this osteoblastic cell function.

Colforsin↗

Changes in the productivity of cytokines and active-oxygen in peripheral blood cells following surgery.

An investigation was carried out on the productivity of cytokines and active-oxygen by peripheral blood cells during the pre- and post-operative periods. While the preoperative production of tumor necrosis factor (TNF) and interleukin-1 alpha (IL-1 alpha) was elevated, that of lymphotoxin (LT) and interferon-gamma (IFN-gamma) were slightly suppressed. In the postoperative period the peak TNF and IL-1 alpha and active-oxygen productivity was elevated, while LT and IFN-gamma productivity was suppressed in patients with an intraoperative bleeding volume of more than 1,000 ml compared to those with that of less than 1,000 ml. Thus, stress stimulates the TNF and IL-1 alpha and active-oxygen producing system, that is, the macrophage-neutrophil system, and suppresses the LT and IFN-gamma system, being, the inflammatory helper T cell system, in the early postoperative period.

Adult↗

Effect of tumour necrosis factor alpha in vivo on human granulocyte oxidative metabolism.

Tumour necrosis factor alpha (TNF alpha) effectively stimulates the oxidative metabolism of human PMN in vitro. Moreover, preincubation of PMN with TNF alpha has been shown to result in an altered response of the target cells to subsequent stimulation. In the present study the response of PMN to stimulation in vitro was investigated in patients with metastasizing malignant melanoma receiving bolus injections of recombinant human TNF alpha as therapy. TNF alpha was given daily for 5 days. Blood samples were taken prior to TNF alpha administration on days 1 to 4 and on day 8. Lucigenin-enhanced chemiluminescence (CL) was used as a sensitive measure of granulocyte oxidative metabolism. PMN were stimulated with TNF alpha, TNF beta, GM-CSF, PMA, opsonized zymosan and f-met-leu-phe. A significant increase in CL responses was detected upon stimulation with TNF alpha, TNF beta and PMA from day 1 to day 3, whereas no significant changes were observed for the background activity or when GM-CSF or opsonized zymosan were used as stimuli. On day 4 all CL responses returned to the day 1 starting level. A further significant decrease was observed on day 8 upon stimulation with TNF alpha, TNF beta and GM-CSF. In contrast, the effect induced by f-met-leu-phe reached a maximum on day 4, but the CL response was found to be at the starting level on day 8. The results indicate that TNF alpha induces significant changes in PMN response to distinct stimuli in vivo. Moreover, it may be possible that continuous daily infusions with TNF alpha induce a hyposensitization of PMN oxidative metabolism.

Acridines↗

Tumour necrosis factor-beta polymorphism is unlikely to determine susceptibility to type 1 (insulin-dependent) diabetes mellitus.

Tumour necrosis factor gene polymorphism has been proposed as a determinant of Type 1 (insulin-dependent) diabetes mellitus. Tumour necrosis factor-beta gene polymorphisms were analysed in 40 North Indian Asian Type 1 diabetic patients and 63 control subjects. A 5.5 kilobase gene fragment was significantly increased among the patients (82.5% vs 52%, pc less than 0.01). A 10.5 kilobase fragment was significantly reduced among the patients (70% vs 90.5%, pc less than 0.02). The 5.5 kilobase fragment was associated with DR3, and was not significantly increased among DR3-positive patients compared with DR3-positive control subjects. The 5.5 kilobase/5.5 kilobase genotype was increased among the diabetic subjects (30% vs 9.5%, pc less than 0.03). The 10.5 kilobase/10.5 kilobase genotype was reduced among the diabetic subjects (17.5% vs 47.5%, pc less than 0.02). The 5.5 kilobase/10.5 kilobase genotype was not significantly associated with disease. These findings contrast with those in a white Caucasian population, suggesting that tumour necrosis factor-beta polymorphisms do not predispose to Type 1 diabetes directly, but are in linkage disequilibrium with disease susceptibility alleles at other MHC loci.

Diabetes Mellitus, Type 1↗

Interstital nephritis in autoimmune hemolytic anemia.

A case is reported of a 15-year-old boy with chronic autoimmune hemolytic anemia who developed renal insufficiency 3 years after splenectomy. An interstitial nephritis with striking lymphocytic infiltrates and sclerosed glomeruli could be demonstrated by percutaneous renal biopsy. Renal symptoms disappeared promptly after corticosteroid therapy. The renal lesions are thought to have arisen as part of the autoimmune disease.

Adolescent↗

Induction of a lymphotoxin-like mediator in peripheral blood and synovial fluid lymphocytes by incubation with synovial fluid from patients with rheumatoid arthritis.

A significantly increased spontaneous cell-mediated cytotoxicity (SCMC) has been reported in synovial fluid lymphocytes (SFL) as compared to peripheral blood lymphocytes (PBL) of patients with rheumatoid arthritis (RA) and that of normal controls [1-3]. To determine whether this increased SCMC activity is due to the production of a lymphokine and related to the production of a lymphotoxin(LT)-like mediator, PBL from normal controls and PBL and SFL from RA patients were incubated either with a human melanoma cell line (IGR 3) or with cell-free synovial fluid (SF) from RA patients. The SF and the cell-free supernatants of the different cultures were tested for LT activity by estimation of inhibition of DNA synthesis of HeLa cell monolayers and they were added to a SCMC assay system using normal PBL and IGR 3 as target. In the supernatants from cocultures of either PBL from controls or PBL and SFL from RA patients with IGR 3 cells, there was no significant difference in LT activity. An LT-like mediator was observed in the supernatants of all lymphocytes cocultured with SF, whereas SF alone and supernatants of lymphocytes alone exhibited little or no LT activity. In a control experiment, LT induction was not observed when normal lymphocytes were cultured with the serum of RA patients. Absorption of the culture supernatants with an insolubilised goat anti-human Ig did not remove LT activity. The demonstrated release of an LT-like mediator from lymphocytes incubated with SF might be one contributing mechanism to the inflammatory joint reaction in RA patients.

Arthritis, Rheumatoid↗