Biomedical subjects

A Sundan

Publications and source records attributed to A Sundan.

At least 55 records · Page 3Linked to original sources

PubMed1996

A non-competitive P55 TNF receptor antibody enhances the specific activity of lymphotoxin-alpha.

In the present study the authors elucidated the involvement of the two TNF receptors (TNFR) in discriminating TNF and lymphotoxin-alpha (LT-alpha) effects in human SW480-beta Gal and KYM-1 cell lines. A non-competitive p55 TNFR monoclonal antibody (MoAb) 44E strongly enhanced LT-alpha-mediated gene regulation and cytotoxicity up to the level of the responses caused by TNF. TNF-induced biological responses were only weakly influenced by 44E. 44E did not affect both binding and the rate of dissociation of the cytokines. The combination of the two p55 TNFR MoAb 44E and Htr5 elicited strong TNF responses, while none of them were agonistic alone. When the p75 TNFR was blocked with Utr1, LT-alpha was still less potent than TNF in mediating CMV promoter activation and cytotoxicity. However, the addition of 44E in the presence of Utr1 merged the LT-alpha dose-response curves with those obtained with TNF plus Utr1. Using antagonistic TNFR MoAb, the authors further showed that TNF functions through both TNFR types while LT-alpha mediates its effects largely via the p55 TNFR. These data suggest that LT-alpha is less potent than TNF due to its lower ability to properly trigger the p55 TNFR and because of its lack of signalling through the p75 TNFR.

Adjuvants, Immunologic↗

PubMed1995

Tumor necrosis factor induces lipopolysaccharide tolerance in a human adenocarcinoma cell line mainly through the TNF p55 receptor.

This study demonstrates that lipopolysaccharide (LPS) mediates induction of transcription factor NF kappa B and activation of the cytomegalovirus (CMV) promoter-enhancer in the SW480 cell line. These cells do not express a functional membrane CD14. The LPS response in SW480 cells was weaker and markedly slower than the tumor necrosis factor (TNF) response. Pretreatment with TNF for 72 h inhibited both TNF, tumor necrosis factor receptor (TNFR) p55, TNFR p75, and LPS-mediated activation of nuclear factor -kappa B (NF kappa B), whereas pretreatment with LPS only inhibited the LPS response. TNFR p55 antibody pretreatment resulted in marked inhibition of the LPS response, while pretreatment with TNFR p75 antiserum only had a weak inhibitory effect. Flowcytometric analysis showed that LPS binding as well as expression of TNFR p55 and TNFR p75 were not affected by LPS or TNF pretreatment, indicating that the observed inhibition is not due to reduction of specific binding sites at the cell surface. The results suggest that LPS signaling in SW480 cells involves intracellular components which may be depleted or inactivated via TNFR p55, indicating that the LPS and TNFR p55 pathways overlap. We propose that TNFR p55 can mediate activation of NF kappa B and cytomegalovirus promoter-enhancer in SW480 cells via two distinct mechanisms, one which is activated only via TNFR p55 and leads to rapid activation of NF kappa B, and another which is overlapping with the LPS pathway.

Adenocarcinoma↗

PubMed1995

Polymorphonuclear granulocytes enhance lipopolysaccharide-induced soluble p75 tumor necrosis factor receptor release from mononuclear cells.

Lipopolysaccharide (LPS), a part of the Gram-negative bacteria cell wall, is a potent inducer of tumor necrosis factor (TNF). TNF is an important mediator in Gram-negative infections such as meningococcal septic shock, but its harmful action can be prevented by the natural occurring soluble (s) TNF receptors (sTNFR) sp55 and sp75. In this study, the effect of LPS on release of sTNFR was investigated. First, we found a selective increase in human whole-blood sp75 TNFR levels following LPS stimulation, accompanied by no increase in sp55. Separating the different blood cell populations, mononuclear cells (PBMC) selectively released sp75 upon LPS stimulation, while LPS induced a minor increase in sp75 release from polymorphonuclear granulocytes. Interestingly, in co-cultures of PBMC and granulocytes, the release of LPS-induced sp75 TNFR was enhanced. Second, adherent monocytes were also found to selectively release sp75 TNFR upon LPS stimulation, where Neisseria meningitidis LPS was found to be 100-1000 times more potent in inducing sp75 release than Escherichia coli LPS. Using flow cytometry, the monocyte membrane distribution of both TNFR were found to be increased after LPS stimulation. Third, human umbilical vein endothelial cells selectively released sp55 TNFR after stimulation with LPS. We conclude that mononuclear and endothelial cells might be the main sources of soluble p75 and p55 TNFR, respectively, observed in Gram-negative sepsis, although these receptors are released in vivo more rapidly than they are in vitro.

Antigens, CD↗

PubMed1995

Effects of anti-CD18 and LPS on CD14 expression on human monocytes.

In this study we show that the cytokine stimulatory effect of LPS on human monocytes is enhanced by addition of monoclonal antibodies against CD18 (alpha CD18 MoAbs). Incubation of monocytes with alpha CD18 MoAbs overnight increased the CD14 expression as detected by Leu-M3, but not with My-4. These results indicate that CD18 participates in LPS-induced TNF-alpha production as well as in regulating CD14 expression on monocytes. Addition of LPS to monocytes resulted in a reduction in the CD14 expression after 1/2, 1, 2 and 4 h, but increased CD14 expression was seen after LPS stimulation overnight. By doing double labelling of the monocyte population for CD14 and CD16 it was found that the reduction in CD14 expression occurred in the CD14+/CD16+ sub-population, while the increase in CD14 expression was seen in both the CD14+/CD16- and the CD14+/CD16+ cells. alpha CD14 MoAbs that were able to inhibit LPS-induced cytokine production from monocytes (3C10 and My-4) were considerably less able to detect the increase in CD14 expression after LPS stimulation than alpha CD14 MoAbs that did not inhibit LPS-induced cytokine production (Leu-M3 and alpha CD14Serva). Our data indicate that My-4 and Leu-M3 define two populations of CD14+ cells on LPS stimulated human monocytes.

Antibodies, Monoclonal↗

PubMed1995

The involvement of CD14 in stimulation of TNF production from peripheral mononuclear cells isolated from PNH patients.

Peripheral blood mononuclear cells (PBMC) from six patients with paroxysmal nocturnal haemoglobinuria (PNH) were analysed by flow cytometry for expression of CD14 and for ability to respond to bacterial lipopolysaccharide and beta 1-4 linked polymannuronic acid by TNF secretion. Expression of cell surface CD14 could not be detected on cells from the PNH patients, whereas the levels of expression of other monocyte antigens, e.g. CD33 and CD13, were comparable to that of cells from healthy subjects. The cells from the patients with PNH responded with secretion of significantly less TNF after stimulation with LPS and polymannuronic acid than mononuclear cells from healthy subjects, suggesting an impaired ability in PNH to respond to bacterial infection by TNF secretion from monocytes. Soluble CD14 appeared to be involved in the residual activation of CD14 negative PBMC, and the sera of these patients contained normal or slightly elevated levels of soluble CD14. After allogeneic bone marrow transplantation in one patient the monocytes expressed CD14 at normal levels and responded normally with respect to their ability to generate TNF upon stimulation.

Adult↗

PubMed1995

Influence of CD14, LBP and BPI in the monocyte response to LPS of different polysaccharide chain length.

In this study we examined the involvement of human serum, recombinant lipopolysaccharide binding protein (rLBP), recombinant (r)CD14, CD14 antibodies and recombinant bactericidal permeability-increasing factor (rBPI) in the induction of TNF by Salmonella minnesota LPS of different polysaccharide chain lengths. Soluble rCD14 and rLBP markedly enhanced LPS 6261 TNF production and to a lesser degree also enhanced TNF production from Re 595 LPS and lipid A DP. Addition of anti-CD14 antibodies resulted in nearly complete inhibition of LPS 6261-induced TNF production and partial inhibition of Re 595 LPS and lipid A DP-induced TNF release. The ability of lipid A MP to induce TNF production increased with addition of rCD14. Addition of rLBP or anti-CD14 antibodies had no detectable effect on lipid A MP-induced TNF production. The effect of rBPI was also tested and the results showed that only the TNF-inducing ability from smooth LPS was completely inhibited by rBPI. Recombinant BPI was considerably less effective in inhibiting Re 595 LPS-induced TNF production, and lipid A DP was not affected by rBPI. Our data suggest that the ability of rLBP, rCD14, CD14 antibodies and rBPI to modulate LPS induced TNF production is strongly dependent on the LPS polysaccharide chain length.

Acute-Phase Proteins↗

PubMed1994

Tumor necrosis factor receptor p75 mediates cell-specific activation of nuclear factor kappa B and induction of human cytomegalovirus enhancer.

The functional role of human tumor necrosis factor receptor (TNFR) p75 was studied by the use of TNFR p75-specific agonistic antibodies. Human SW480T adenocarcinoma cells, stably transfected with a reporter construct containing beta-galactosidase under the control of human cytomegalovirus immediate early enhancer, were stimulated with anti-TNFR p75 polyclonal antiserum or monoclonal antibodies followed by measurement of beta-galactosidase activity and analysis by electrophoretic mobility shift assays. It was found that cross-linking of TNFR p75 led to strong induction of the human cytomegalovirus enhancer as well as activation of nuclear factor-kappa B (NF-kappa B). Stimulation of TNFR p75 also mediated activation of NF-kappa B in human KYM-1 rhabdomyosarcoma cells but not in other cell types such as U937 and HL-60 monocytic cells or in Eahy 926 endothelial cells. NF-kappa B activation induced by TNFR p75 was delayed approximately 15 min compared with NF-kappa B activation induced by TNFR p55, indicating that the two TNFRs activate NF-kappa B through different signaling pathways. The data presented in this study identify intracellular responses mediated by TNFR p75 which have not been reported previously and suggest that TNFR p75-induced activation of NF-kappa B is strictly cell type-specific.

Base Sequence↗

PubMed1994

Soluble CD14 from urine copurifies with a potent inducer of cytokines.

Here we report that soluble CD14 isolated from the urine of nephrotic patients (uCD14) contains a potent cytokine inducing activity. CD14 derived from urine appeared to consist of two major polypeptides of about 54 and 48 kDa. In uCD14 isolated from three different nephrotic patients the cytokine-inducing activity appeared to co-migrate with the 48-kDa polypeptide which upon sequencing had the same N-terminal sequence as native CD14. Treatment of human monocytes and the human astrocytoma cell line U373 with uCD14 resulted in a strong secretion of tumor necrosis factor (TNF) and interleukin-6, respectively. The cytokine-inducing activity of the uCD14 preparations was unaffected by the absence of serum. This is in contrast to the activation of human monocytes and U373 cells by lipopolysaccharide (LPS) which is highly dependent on the presence of serum. The cytokine-inducing activity was not affected by LPS-binding protein (LBP) or polyclonal rabbit antibodies against LBP. The TNF-inducing activity of uCD14 was also heat labile in contrast to the cytokine-inducing activity of LPS, which was relatively heat resistant. The results suggest that CD14 may exist in at least two forms of which one is involved in cytokine induction.

Acute-Phase Proteins↗

PubMed1994

Involvement of the tumor necrosis factor receptor p75 in mediating cytotoxicity and gene regulating activities.

Using agonistic antibodies (Ab) we have examined whether the 75-kDa chain of the tumor necrosis factor receptor (p75 TNFR) is capable of mediating cytotoxic response and gene regulation alone or in cooperation with p55 TNFR. Addition of an anti-p75 TNFR polyclonal antiserum or anti-p75 monoclonal antibody (mAb) plus anti-immunoglobulin (Ig) led to cytotoxic response of human KYM-1 rhabdomyosarcoma cells. Anti-p75 mAb alone had no effect pointing out the importance of strong receptor stimulation for signal transduction into the cell. Simultaneous triggering of both the p55 and p75 TNFR by agonistic Ab resulted in additive cytotoxic action on KYM-1 cells. The anti-p75 mAb 3H5, directed to a non-TNF binding site on the human p75 TNFR, was used to confirm further the ability of the p75 TNFR to potentiate p55 TNFR-mediated cell death. While exhibiting no cytotoxicity by its own, 3H5 significantly augmented the cytotoxic effect of the anti-p55 mAb htr9 towards KYM-1 cells. Neither the anti-p75 TNFR antiserum nor anti-p75 mAb were cytotoxic for human U937 cells suggesting that the cytolysis resulting from p75 TNFR cross-linking is cell specific. Noteworthy, stimulation of the p75 TNFR with mAb plus anti-Ig or polyclonal antiserum led to a marked enhancement of the p55 TNFR-induced U937 cell death, indicating collaboration between the two TNFR in induction of cytotoxicity also in this cell line. However, 3H5 mAb did not affect the ability of anti-p55 mAb to lyse U937 cells. Altogether, these data demonstrate the difference between KYM-1 and U937 cell lines with respect to the role for the p75 TNFR in mediating cytotoxicity. Both TNFR were found to mediate cytomegalovirus (CMV) promoter activation in human SW480T-beta Gal cells and nuclear transcription factor kappa B (NF-kappa B) induction in this cell line as well as in KYM-1 cells. It was demonstrated for the first time that independent stimulation of both TNFR resulted in an additive effect on the CMV promoter activation and induction of the NF-kappa B. Taken together, these results indicate that the p75 TNFR induces cytotoxicity in a cell-specific manner and potentiates p55 TNFR-mediated cytotoxic response and gene regulation.

Amino Acid Sequence↗

PubMed1993

The release of soluble p55 TNF receptor from U937 cells studied by a new p55 immunoassay.

A highly specific and sensitive immunoassay for soluble p55 tumor necrosis factor receptor (TNFR) has been established. The immunoassay was based on a newly developed monoclonal antibody (IV4E) recognizing a non-TNF-binding site of the p55 TNFR. The IV4E antibody immunoprecipitated a 55 kDa TNF binding protein from HL-60 cells. No binding of IV4E to the p75 TNFR could be detected. Bound TNFR to IV4E was detected with digoxigenin (DIG) labeled TNF. This assay could detect down to 300 pg/ml of soluble p55, which represents an 8-10-fold increase in sensitivity compared to earlier developed immunoassays. The assay was specific for soluble p55 TNFR present in serum and cell culture supernatants, since addition of excess unlabeled TNF together with DIG labeled TNF inhibited the signal. TNF concentrations up to 10 ng/ml in the TNFR sample did not affect the assay, indicating that TNFRs can be measured in samples containing TNF. The new immunoassay was used to study the mechanisms underlying the release of soluble p55 TNFR from U937 cells stimulated with TPA. The TPA induced release of soluble p55 TNFR from U937 cells occurred in two phases. First, a rapid increase of soluble p55 was observed after the addition of TPA. Later, the release of p55 occurred at a slower rate, and this release was inhibited by known inhibitors of protein synthesis and intracellular transport. Addition of TPA increased the p55 mRNA expression in U937 cells. The results suggest that TPA induces both release and new synthesis of p55 in U937 cells.

Animals↗

PubMed1993

The involvement of CD14 in stimulation of cytokine production by uronic acid polymers.

In this study the molecular mechanisms behind the stimulatory activities of the uronic acid polymers poly mannuronic acid (poly M), high M alginate and oxidized cellulose (C60XY) were investigated and compared with lipopolysaccharide (LPS). The cytokine-inducing abilities of the uronic acid polymers and LPS were examined on CD14-positive human monocytes and CD14-negative U373 astrocytoma cells. It was found that LPS induced monocytes and U373 cells to produce tumor necrosis factor (TNF) and interleukin(IL)-6, respectively, by different mechanisms. The poly uronic acids induced monocytes to produce TNF, but with 100-1000 times less potency compared to LPS. On U373 cells, LPS at concentrations > or = 32 ng/ml resulted in a dose-related IL-6 production, whereas the poly uronic acids had negligible effects even at 1 mg/ml. The binding data demonstrate that only the CD14-positive monocytes in the peripheral blood mononuclear cells population bound poly M. Furthermore, poly M was found to bind to CD14 in the presence of serum. Antibodies against CD14 also inhibited the TNF-inducing activity of the three uronic acid polymers tested. In conclusion, these results demonstrate that uronic acid polymers induce TNF production through mechanisms which involve CD14.

Alginates↗

PubMed1993

Gene expression and secretion of cytokines and cytokine receptors from highly purified CD56+ natural killer cells stimulated with interleukin-2, interleukin-7 and interleukin-12.

Interleukin (IL)-2 IL-7 and IL-12 stimulate the generation of lymphokine-activated killer activity and proliferation in natural killer (NK) cells by different mechanisms. In this study, we have compared the ability of IL-2, IL-7 and IL-12 to induce expression of cytokines and cytokine receptors both at the gene and protein level. IL-2 and IL-12 stimulated the CD56+ NK cells to release significant amounts of soluble p55 and p75 tumor necrosis factor receptor (TNFR), whereas less amounts of soluble TNFR were detected in IL-7-stimulated cultures. The p55 and p75 TNFR mRNA were expressed in resting NK cells, and no further induction was observed after cytokine-stimulation. Compared to the effects of IL-2, IL-7 induced lower, but substantial levels of granulocyte-macrophage colony-stimulating factor (GM-CSF) mRNA, and IL-7 was a more potent GM-CSF-inducing stimulus than IL-12. IL-12 induced higher levels of interferon-gamma (IFN-gamma) mRNA than did IL-2, and IL-7 only weakly influenced the IFN-gamma expression. In accordance with the mRNA studies, IL-7 induced the secretion of high amounts of GM-CSF and no or low levels of IFN-gamma, whereas high amounts of IFN-gamma and low levels of GM-CSF were detected in supernatants from IL-12-stimulated NK cells. In conclusion, IL-2, IL-7 and IL-12 differentially regulate expression of cytokines and cytokine receptors both at the gene and protein level.

Animals↗

PubMed1993

Tumor necrosis factor, interleukin-1, and interleukin-6 in normal human pregnancy.

OBJECTIVE: Our purpose was to investigate the cytokines, tumor necrosis factor, interleukin-1, and interleukin-6 in normal human pregnancy and labor. STUDY DESIGN: Bioassays were used to measure these factors in extraembryonic coelomic fluid, amniotic fluid, placenta, and maternal and cord serum. RESULTS: Little or no tumor necrosis factor, interleukin-1, or interleukin-6 was found in coelomic fluid or amniotic fluid in the first trimester. Interleukin-6 appeared in second-trimester amniotic fluid. At term tumor necrosis factor was present (median 17 pg/ml) and increased with the onset of labor (median 58 pg/ml), as did interleukin-1 (median 188 to 680 pg/ml) and interleukin-6 (median 399 to 4800 pg/ml). Maternal serum interleukin-6 increased during pregnancy with a further increment with the onset of labor. Cord interleukin-6 also increased with labor but at a lower level. CONCLUSION: The cytokines tumor necrosis factor, interleukin-1, and interleukin-6 may play a role in the onset of normal labor.

Amniotic Fluid↗

PubMed1993

Synergistic effects of interleukin 4 and interleukin 12 on NK cell proliferation.

Our previous studies have demonstrated that interleukin12 (IL-12) (cytotoxic lymphocyte maturation factor/NK cell stimulatory factor) and IL-7 alone have the ability to generate high LAK activity and low proliferative activity in CD56+ NK cells. This study was undertaken to examine the influence of IL-4 on the IL-12-induced activation of CD56+ NK cells. IL-4 did not affect the IL-12-induced generation of LAK activity in CD56+ cells, in contrast to an inhibition of IL-2 and IL-7-induced LAK activity. Most interestingly, the combination of IL-4 and IL-12 resulted in a synergistic proliferative activity (8-fold) in the CD56+ NK cells, and a marked increase in the cell yield at day 5 was detected. Furthermore, the potent effect of IL-4 on IL-12-induced proliferation was restricted to the CD56+ NK cells, as CD56- cell populations were found unresponsive to the combination of IL-4 and IL-12. Furthermore, IL-4 induced a slight increase in the IL-12-stimulated TNF production. IL-12 enhanced the IL-12 receptor (R) expression and IL-4R expression in the CD56+ NK cells. Combined treatment with IL-12 and IL-4 further enhanced the IL-12R expression, most prominently in the CD56+, CD16- NK subpopulation. The increased IL-4R expression induced by IL-12 and the increased IL-12R expression induced by IL-4 may explain the synergistic proliferative activity detected in response to IL-12 and IL-4. IL-4 seems to possess unique stimulatory properties towards resting CD56+ NK cells, when used as a costimulus with IL-12.

Antigens, CD↗

PubMed1993

High concentrations of the soluble p55 tumour necrosis factor receptor in human seminal plasma.

Soluble TNFRs (tumour necrosis factor receptors) inhibit in-vivo and in-vitro bioactivities of TNF, and thus the secretion of soluble TNFRs could be a physiological principle to attenuate the bioactivities of TNF. Two types of TNFR have been identified and both forms can be released from cells. In this study, soluble TNFRs in seminal plasma from three groups of men were analysed: from men with normal semen quality (n = 32), with reduced semen quality (n = 7) and vasectomized men (n = 3). Sensitive and specific enzyme-linked immunosorbent assays were utilized to detect soluble TNFRs in seminal plasma, based on capture antibodies directed against non-TNF-binding sites of the TNFRs and digoxigenin (DIG)-labelled TNF. The mean +/- standard deviation levels of p55 TNFR were 56.4 +/- 20, 64.4 +/- 17 and 45.4 +/- 5 ng/ml in the three groups, respectively. The concentration of p75 TNFR was < 1 ng/ml in all groups. The results suggest an exclusive existence of high amounts of the soluble p55 TNFR in seminal plasma. Seminal plasma from vasectomized men contained p55 TNFR at approximately the same levels as the specimen from the two other groups, indicating that the source of p55 TNFR is not the testis but rather some tissue more distal in the male genital tract, such as the prostate or the seminal vesicles. The soluble p55 TNFR was purified from human seminal plasma, using affinity and gel filtration chromatography. Further characterization of the purified p55 revealed a protein with a molecular weight of approximately 22 kDa, both under reducing and non-reducing conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromatography, Affinity↗

PubMed1993

Similar mechanisms of action of defined polysaccharides and lipopolysaccharides: characterization of binding and tumor necrosis factor alpha induction.

Little has been reported about the effects of different polysaccharides on cytokine production from human monocytes. In this study, we show that several well-defined polysaccharides, including polymers with different sizes of beta 1-4-linked D-mannuronic acid (poly-M, high-M alginate, and M-blocks) and cellulose oxidized in the C-6 position, induced human monocytes to produce tumor necrosis factor alpha (TNF-alpha). Poly-M was the most efficient polysaccharide tested and, on a weight basis, was approximately as efficient as lipopolysaccharide (LPS) from Escherichia coli. TNF-alpha production was shown to depend strongly on the molecular weights of poly-M and high-M alginate, with maximal TNF-alpha production occurring at molecular weights above 50,000 and 200,000, respectively. G-blocks, alpha 1-4-linked L-guluronic acid polymers that did not induce cytokine production from monocytes, reduced the cytokine production induced by the beta 1-4-linked polyuronic acids and LPS. Furthermore, both G-blocks and LPS were found to inhibit the binding of poly-M to monocytes, as measured by flow cytometry. In addition, we found that the binding of LPS to monocytes was inhibited by G-blocks, M-blocks, and poly-M. Our results indicate that beta 1-4-linked polyuronic acids and LPS may stimulate monocytes to produce TNF-alpha by similar mechanisms and may bind to a common receptor.

Biological Assay↗

PubMed1992

Soluble CD14 participates in the response of cells to lipopolysaccharide.

CD14 is a 55-kD protein found both as a glycosylphosphatidyl inositol-linked protein on the surface of mononuclear phagocytes and as a soluble protein in the blood. CD14 on the cell membrane (mCD14) has been shown to serve as a receptor for complexes of lipopolysaccharide (LPS) with LPS binding protein, but a function for soluble CD14 (sCD14) has not been described. Here we show that sCD14 enables responses to LPS by cells that do not express CD14. We have examined induction of endothelial-leukocyte adhesion molecule 1 expression by human umbilical vein endothelial cells, interleukin 6 secretion by U373 astrocytoma cells, and cytotoxicity of bovine endothelial cells. None of these cell types express mCD14, yet all respond to LPS in a serum-dependent fashion, and all responses are completely blocked by anti-CD14 antibodies. Immunodepletion of sCD14 from serum prevents responses to LPS, and the responses are restored by addition of sCD14. These studies suggest that a surface anchor is not needed for the function of CD14 and further imply that sCD14 must bind to additional proteins on the cell surface to associate with the cell and transduce a signal. They also indicate that sCD14 may have an important role in potentiating responses to LPS in cells lacking mCD14.

Animals↗

PubMed1992

Butylated hydroxyanisole specifically inhibits tumor necrosis factor-induced cytotoxicity and growth enhancement.

The effect of commonly used food antioxidants on recombinant tumor necrosis factor alpha (rTNF-alpha)-induced cytotoxicity, growth enhancement and adhesion has been evaluated. Butylated hydroxyanisole (BHA) and 4-hydroxymethyl-2,6-di-t-butylphenol (HBP) were the only two of nine antioxidants that completely inhibited rTNF-alpha-induced cytotoxicity in L929 and WEHI 164 fibrosarcoma cells. Ethoxyquin, propyl gallate and butylated hydroquinone only partially inhibited rTNF-alpha-induced cytotoxicity, while the antioxidants butylated hydroxytoluene (BHT), alpha-tocopherol, ascorbic acid and thiodipropionic acid had minimal effects. The only difference between the molecular structure of the efficient HBP and the non-efficient BHT, is a hydroxymethyl group instead of a hydroxyl group on the phenolic ring. Neither BHA nor BHT inhibited the activation of NF kappa B after 10 or 60 min challenge with rTNF-alpha in L929 cells. BHA also inhibited rTNF-alpha-induced, but not rIL-1 beta-induced growth enhancement in FS-4 fibroblasts. Further, BHA blocked both rTNF-alpha-induced and rIL-1 beta-induced prostaglandin E2 synthesis in FS-4 fibroblasts. BHA inhibited the rTNF-alpha-induced release of arachidonic acid in both FS-4 and L929 cells, suggesting that BHA inhibits cellular phospholipase(s). Neither alpha-tocopherol nor BHA inhibited rTNF-alpha-induced adhesiveness of human endothelial cells. The results indicate that BHA is a specific and potent inhibitor of rTNF-alpha- and rTNF-beta-induced cytotoxicity, as well as of rTNF-alpha-induced growth enhancement.

Animals↗