[Preliminary evaluation and mechanism of adipose-derived stem cell transplantation from allogenic diabetic rats in the treatment of diabetic rat wounds]

Objective: To investigate whether adipose-derived stem cells (ASCs) from allogeneic diabetic rats can promote wound healing in diabetic rats or not and the mechanism. Methods: (1) Fifty-six male Wistar rats aged 12-16 weeks were divided into diabetic group and healthy group according to the random number table (the same grouping method below), with 28 rats in each group. Rats in healthy group were not treated with any treatment. Rats in diabetic group were injected with 10 g/L streptozotocin 60 mg/kg intraperitoneally in one time to establish the diabetic model. Four rats in diabetic group and 4 rats in healthy group were selected according to the random number table, and the adipose tissue in the inguinal region was taken to culture and purify ASCs, so as to obtain healthy rat-derived ASCs (hereinafter referred to as nASCs) and diabetic rat-derived ASCs (hereinafter referred to as dASCs). The third passage of nASCs (n=3) and dASCs (n=3) were taken, and the positive expression rates of cell surface differentiation antigens CD105, CD31, CD34, and CD44 were detected with flow cytometer for defining ASCs purity. (2) The rest 24 rats in healthy group and 24 rats in diabetic group were used to make three round full-thickness skin defect wounds with a diameter of 12 mm on the back of each rat. Immediately after injury, phosphate buffer saline (PBS), nASCs of 2×10(7)/mL, and dASCs of 2×10(7)/mL each in the volume of 0.5 mL were subcutaneously injected into three wounds and their margins of each rat, respectively. On post injury day (PID) 1, 3, 7, and 12, 6 rats in each group were selected according to the random number table to calculate the wound area, and the wound tissue was stained with hematoxylin-eosin to observe the histological morphology of the wound. (3) Human ASCs (hASCs) were subcultured, and the 4th to 7th passage of cells were used for the subsequent experiments. The hASCs were divided into 7 groups, with 12 samples in each group. Cells in blank control group were cultured with mesenchymal stem cell culture medium, and cells in simple advanced glycation end products (AGEs) group, simple protein group, simple high glucose group, simple high osmotic pressure group, AGEs-high glucose combination group, and protein-high osmotic pressure combination group were cultured with mesenchymal stem cell culture medium containing a final mass concentration of 100 mg/L AGEs, 100 mg/L bovine serum albumin (BSA), 28 mmol/L D-glucose, 28 mmol/L mannitol, 100 mg/L AGEs+ 28 mmol/L D-glucose, 100 mg/L BSA+ 28 mmol/L mannitol, respectively. Cell proliferation was detected by cell counting kit 8 at post culture hour (PCH) 2 and on post culture day (PCD) 2, 4 and 6. (4) The hASCs were divided into blank control group, simple AGE group, simple high glucose group, and AGE-high glucose combination group, with 12 samples in each group, which were treated the same as corresponding groups in experiment (3). On PCD 0, 2, 4, and 6, the positive expression rates of cell surface differentiation antigens CD105, CD44, and CD45 were detected by flow cytometer to estimate their homeostasis. (5) The hASCs were divided into AGE-high glucose combination group and protein-high osmotic pressure combination group, with 9 samples in each group, which were treated the same as corresponding groups in experiment (3). On PCD 2, 4, and 6, the expression of intracellular protein was detected by cyanine 3-streptavidin double-antibody sandwich technique. Data were processed with analysis of variance for factorial design, least significant difference test, and Bonferroni correction. Results: (1) The positive expression rates of CD44 in nASCs and dASCs were both higher than 96%, the positive expression rates of CD31 and CD34 were low, and the positive expression rates of CD105 were about 40%, which basically met the purity requirements. (2) The areas of wounds treated by three methods in rats of healthy group and diabetic group were similar on PID 1 (P>0.05). In healthy group, compared with (0.682 1±0.078 9), (0.314 3±0.113 7), and (0.064 3±0.002 1) cm(2) of the PBS-treated wounds in rats, the area of nASCs-treated wounds in rats decreased significantly on PID 3, 7, and 12 [(0.464 1±0.092 6), (0.223 9±0.072 7), and (0.034 3±0.012 5) cm(2), P<0.05], the area of dASCs-treated wounds in rats decreased significantly on PID 3 and 12 [(0.514 1±0.124 1) and (0.043 7±0.032 8) cm(2), P<0.05] but was not obviously changed on PID 7 [(0.274 2±0.062 5) cm(2), P>0.05]. Compared with those of the dASCs-treated wounds of rats within the same group, the area of the nASCs-treated wounds of rats in healthy group decreased significantly on PID 3 and 7 (P<0.05) but was not obviously changed on PID 12 (P>0.05). In diabetic group, compared with (0.853 5±0.204 8), (0.670 5±0.164 8), and (0.131 4±0.074 4) cm(2) of the PBS-treated wounds in rats, the area of nASCs-treated wounds in rats decreased significantly on PID 3, 7, and 12 [(0.633 4±0.132 5), (0.331 8±0.023 5), and (0.074 2±0.003 8) cm(2), P<0.05], the area of dASCs-treated wounds in rats decreased significantly on PID 3 [(0.773 6±0.182 2) cm(2), P<0.05] but was not obviously changed on PID 7 and 12 [(0.510 6±0.192 2) and (0.114 4±0.003 1) cm(2), P>0.05]. Compared with the dASCs-treated wounds of rats within the same group, the area of the nASCs-treated wounds of rats in diabetic group was not obviously changed on PID 3 and 7 (P>0.05) but decreased significantly on PID 12 (P<0.05). There was no obvious difference in histological morphology of the wounds treated with three methods in rats of each group on PID 1. On PID 3, a small amount of microvessels were formed in the wounds treated with nASCs and dASCs of rats in both groups, but microvessel formation was almost undetected in the PBS-treated wounds. On PID 7, more small blood vessels and fibroblasts (Fbs) were observed in the wounds treated with nASCs and dASCs of rats in both groups, but the small blood vessels and Fbs were slightly less in the PBS-treated wounds. On PID 12, the wounds treated with nASCs and dASCs of rats in the two groups were covered by epithelial tissue, the granulation tissue in the PBS-treated wounds of rats in healthy group was not obvious, and the PBS-treated wounds of rats in diabetic group were not completely epithelialized. (3) Compared with those of blank control group, the cell number of hASCs in simple AGEs group decreased significantly on PCD 2, 4, and 6 (P<0.05), which increased significantly on PCD 2 and 4 in simple high glucose group (P<0.05), and that in AGEs-high glucose combination group decreased significantly on PCD 4 and 6 (P<0.05). (4) Compared with that on PCD 4 within the same group, the positive expression rate of CD105 in hASCs decreased significantly in blank control group, simple AGEs group, and AGEs-high glucose combination group on PCD 6 (P<0.05). The positive expression rate of CD44 was higher than 95%, and that of CD45 was less than 2% in hASCs of each group at each time point. (5) Detection values of 7 proteins were located in the confidence interval. The expression levels of basic fibroblast growth factor and tissue inhibitor of metalloproteinase-1 in hASCs of AGEs-high glucose combination group and protein-high osmotic pressure combination group showed increasing trend with the prolongation of culture time. The expression level of human monocyte chemoattractant protein 1 (MCP-1) in hASCs of AGEs-high glucose combination group showed increasing trend with the prolongation of culture time, while the expression level of growth-regulated oncogene (GRO) on PCD 6 was significantly higher than that on PCD 4 within the same group (P<0.05); the expression levels of MCP-1 and GRO in hASCs of protein-high osmotic pressure combination group showed decreasing trend with the prolongation of culture time. The expression level of follistatin in hASCs of protein-high osmotic pressure combination group decreased obviously on PCD 4, while that in hASCs of AGEs-high glucose combination group was significantly lower on PCD 6 than that on PCD 4 (P<0.05). The expression level of vascular endothelial growth factor (VEGF) in hASCs of protein-high osmotic pressure combination group decreased gradually with the prolongation of culture time, while that in hASCs of AGEs-high glucose combination group on PCD 4 decreased significantly as compared with that on PCD 2 (P<0.05). The expression level of urokinase-type plasminogen activator receptor in hASCs of protein-high osmotic pressure combination group on PCD 6 was significantly higher than that on PCD 4 within the same group (P<0.05) and that of AGEs-high glucose combination group on PCD 6 (P<0.05). Conclusions: Both nASCs and dASCs can promote wound healing in rats with simple defect injury, but dASCs have no significant effect on wound healing in rats with diabetes mellitus, which may be related to the inhibition of ASCs proliferation and the influence of high glucose and AGEs intervention on their homeostasis and secretory function.

Development of Integrated Device of Trace Bloodstains Imaging and Age Analysis

Abstract

Objective To develop a device of trace bloodstains imaging and age analysis, so as to provide a non-destructive, simple and objective method for age estimation of bloodstains at the crime scene. Methods Based on the principle of digital imaging and color pattern analysis, the mobile terminal of the device was used to collect images of bloodstains of different ages. The time-dependent pattern of 6 parameters （R, G, B, C, Y, M） reflecting the changes of color of images of different ages was obtained by computer image analysis. A multiparameter comprehensive inference equation of bloodstains age was established and embedded into the device software to realize the intelligent inference of the bloodstains age. Then the capability and reliability of the device was verified. Results This integrated device of bloodstains imaging and age analysis could quickly collect bloodstains at the crime scene and automatically analyze and infer the age of bloodstains combined with related intelligence software. In the blind test, the detection accuracy of this device was 95% in both natural light airtight group and dark airtight group, and 80% in the natural light ventilation group. Conclusion The integrated device of trace bloodstains imaging and age analysis can be used in a simple manner, which provides a new objective method for bloodstains age estimation.

Comparative analysis of bilirubin in correlation to albumin between nephrotic syndrome patients and postoperative gastroparesis syndrome patients

This study aimed to disclose the potential causality of low bilirubin in patients with nephrotic syndrome (NS). Correlation analysis was carried out on total bilirubin (TBIL) to serum albumin (ALB), urine protein (Upr), and urinary microalbumin/creatinine (Umalb/cr) for three groups in a case-control study. P < 0.001 was observed for TBIL, ALB, Umalb/cr, and Upr between the NS and chronic nephritis (CN) groups, and P values of 0.0001, 1.000, 0.0001, and 0.0001 were observed for TBIL, ALB, Umalb/cr, and Upr, respectively, between the postoperative gastroparesis (PGS) and CN groups. The values of r and P in correlation to TBIL were 0.549 and 0.000 for ALB, -0.405 and 0.000 for Umalb/cr, and -0.448 and 0.000 for Upr in the NS group; -0.007 and 0.959 for ALB, 0.213 and 0.091 for Umalb/cr, and -0.082 and 0.519 for Upr in the PGS group; and 0.509 and 0.000 for ALB, -0.431 and 0.000 for Umalb/cr, and -0.362 and 0.002 for Upr in the CN group. A probable causality is implied between the low level of blood bilirubin and its loss in urine in NS patients. This conclusion may provide a theoretical basis for the feasibility of therapies against oxidative stress in NS patients.

Matrix metalloproteinase activity inactivates the CXC chemokine stromal cell-derived factor-1

Chemokines provide directional cues for leukocyte migration and activation that are essential for normal leukocytic trafficking and for host responses during processes such as inflammation, infection, and cancer. Recently we reported that matrix metalloproteinases (MMPs) modulate the activity of the CC chemokine monocyte chemoattractant protein-3 by selective proteolysis to release the N-terminal tetrapeptide. Here we report the N-terminal processing, also at position 4-5, of the CXC chemokines stromal cell-derived factor (SDF)-1alpha and beta by MMP-2 (gelatinase A). Robustness of the MMP family for chemokine cleavage was revealed from identical cleavage site specificity of MMPs 1, 3, 9, 13, and 14 (MT1-MMP) toward SDF-1; selectivity was indicated by absence of cleavage by MMPs 7 and 8. Efficient cleavage of SDF-1alpha by MMP-2 is the result of a strong interaction with the MMP hemopexin C domain at an exosite that overlaps the monocyte chemoattractant protein-3 binding site. The association of SDF-1alpha with different glycosaminoglycans did not inhibit cleavage. MMP cleavage of SDF-1alpha resulted in loss of binding to its cognate receptor CXCR-4. This was reflected in a loss of chemoattractant activity for CD34(+) hematopoietic progenitor stem cells and pre-B cells, and unlike full-length SDF-1alpha, the MMP-cleaved chemokine was unable to block CXCR-4-dependent human immunodeficiency virus-1 infection of CD4(+) cells. These data suggest that MMPs may be important regulatory proteases in attenuating SDF-1 function and point to a deep convergence of two important networks, chemokines and MMPs, to regulate leukocytic activity in vivo.

[High performance liquid chromatographic determination of domoic acid in shellfish samples]

Domoic acid in shellfish samples was determined by HPLC with DAD/UV detector at 242 nm. Samples were extracted with methanol-water followed by clean-up of the extracts with strong anion exchange solid phase extraction cartridge(3 mL LC-SAX). Zorbax SB-C18 column, 150 mm x 4.6 mm i.d., and mobile phase of acetonitrile-0.1% aqueous trifluoroacetic acid(13:87, V/V) were used for the assay. The quantitative analysis was performed with external standard. The calibration curve of domoic acid was linear in the range of 1.0 m/L-25.0 mg/L and the detection limit was ca. 0.2 microgram/g.

The ligands of CXC chemokine receptor 3, I-TAC, Mig, and IP10, are natural antagonists for CCR3

Th1 and Th2 lymphocytes express a different repertoire of chemokine receptors (CCRs). CXCR3, the receptor for I-TAC (interferon-inducible T cell alpha-chemoattractant), Mig (monokine induced by gamma-interferon), and IP10 (interferon-inducible protein 10), is expressed preferentially on Th1 cells, whereas CCR3, the receptor for eotaxin and several other CC chemokines, is characteristic of Th2 cells. While studying responses that are mediated by these two receptors, we found that the agonists for CXCR3 act as antagonists for CCR3. I-TAC, Mig, and IP10 compete for the binding of eotaxin to CCR3-bearing cells and inhibit migration and Ca(2+) changes induced in such cells by stimulation with eotaxin, eotaxin-2, MCP-2 (monocyte chemottractant protein-2), MCP-3, MCP-4, and RANTES (regulated on activation normal T cell expressed and secreted). A hybrid chemokine generated by substituting the first eight NH(2)-terminal residues of eotaxin with those of I-TAC bound CCR3 with higher affinity than eotaxin or I-TAC (3- and 10-fold, respectively). The hybrid was 5-fold more potent than I-TAC as an inhibitor of eotaxin activity and was effective at concentrations as low as 5 nm. None of the antagonists described induced the internalization of CCR3, indicating that they lack agonistic effects and thus qualify as pure antagonists. These results suggest that chemokines that attract Th1 cells via CXCR3 can concomitantly block the migration of Th2 cells in response to CCR3 ligands, thus enhancing the polarization of T cell recruitment.

Inflammation dampened by gelatinase A cleavage of monocyte chemoattractant protein-3

Tissue degradation by the matrix metalloproteinase gelatinase A is pivotal to inflammation and metastases. Recognizing the catalytic importance of substrate-binding exosites outside the catalytic domain, we screened for extracellular substrates using the gelatinase A hemopexin domain as bait in the yeast two-hybrid system. Monocyte chemoattractant protein-3 (MCP-3) was identified as a physiological substrate of gelatinase A. Cleaved MCP-3 binds to CC-chemokine receptors-1, -2, and -3, but no longer induces calcium fluxes or promotes chemotaxis, and instead acts as a general chemokine antagonist that dampens inflammation. This suggests that matrix metalloproteinases are both effectors and regulators of the inflammatory response.

Inflammation dampened by gelatinase A cleavage of monocyte chemoattractant protein-3

Tissue degradation by the matrix metalloproteinase gelatinase A is pivotal to inflammation and metastases. Recognizing the catalytic importance of substrate-binding exosites outside the catalytic domain, we screened for extracellular substrates using the gelatinase A hemopexin domain as bait in the yeast two-hybrid system. Monocyte chemoattractant protein-3 (MCP-3) was identified as a physiological substrate of gelatinase A. Cleaved MCP-3 binds to CC-chemokine receptors-1, -2, and -3, but no longer induces calcium fluxes or promotes chemotaxis, and instead acts as a general chemokine antagonist that dampens inflammation. This suggests that matrix metalloproteinases are both effectors and regulators of the inflammatory response.

N-terminal peptides of stromal cell-derived factor-1 with CXC chemokine receptor 4 agonist and antagonist activities

Peptides corresponding to the N-terminal 9 residues of stromal cell-derived factor-1 (SDF-1) have SDF-1 activity. SDF-1, 1-8, 1-9, 1-9 dimer, and 1-17 induced intracellular calcium and chemotaxis in T lymphocytes and CEM cells and bound to CXC chemokine receptor 4 (CXCR4). The peptides had similar activities to SDF-1 but were less potent. Whereas native SDF-1 had half-maximal chemoattractant activity at 5 nM, the 1-9 dimer required 500 nM and was therefore 100-fold less potent. The 1-17 and a 1-9 monomer analog were 4- and 36-fold, respectively, less potent than the 1-9 dimer. Both the chemotactic and calcium response of the 1-9 dimer was inhibited by an antibody to CXCR4. The basis for the enhanced activity of the dimer form of SDF-1, 1-9 is uncertain, but it could involve an additional fortuitous binding site on the 1-9 peptide in addition to the normal SDF-1, 1-9 site. A 1-9 analog, 1-9[P2G] dimer, was found to be a CXCR4 antagonist. Overall this study shows that the N-terminal peptides are CXCR4 agonists or antagonists, and these could be leads for high affinity ligands.

Solution structure and basis for functional activity of stromal cell-derived factor-1; dissociation of CXCR4 activation from binding and inhibition of HIV-1

The three-dimensional structure of stromal cell-derived factor-1 (SDF-1) was determined by NMR spectroscopy. SDF-1 is a monomer with a disordered N-terminal region (residues 1-8), and differs from other chemokines in the packing of the hydrophobic core and surface charge distribution. Results with analogs showed that the N-terminal eight residues formed an important receptor binding site; however, only Lys-1 and Pro-2 were directly involved in receptor activation. Modification to Lys-1 and/or Pro-2 resulted in loss of activity, but generated potent SDF-1 antagonists. Residues 12-17 of the loop region, which we term the RFFESH motif, unlike the N-terminal region, were well defined in the SDF-1 structure. The RFFESH formed a receptor binding site, which we propose to be an important initial docking site of SDF-1 with its receptor. The ability of the SDF-1 analogs to block HIV-1 entry via CXCR4, which is a HIV-1 coreceptor for the virus in addition to being the receptor for SDF-1, correlated with their affinity for CXCR4. Activation of the receptor is not required for HIV-1 inhibition.

An antagonist of monocyte chemoattractant protein 1 (MCP-1) inhibits arthritis in the MRL-lpr mouse model

An antagonist of human monocyte chemoattractant protein (MCP)-1, which consists of MCP-1(9-76), had previously been characterized and shown to inhibit MCP-1 activity in vitro. To test the hypothesis that, by inhibiting endogenous MCP-1, the antagonist has antiinflammatory activity in vivo, we examined its effect in the MRL-lpr mouse model of arthritis. This strain spontaneously develops a chronic inflammatory arthritis that is similar to human rheumatoid arthritis. Daily injection of the antagonist, MCP-1(9-76), prevented the onset of arthritis as monitored by measuring joint swelling and by histopathological evaluation of the joints. In contrast, controls treated with native MCP-1 had enhanced arthritis symptoms, indicating that the inhibitory effect is specific to the antagonist. In experiments where the antagonist was given only after the disease had already developed, there was a marked reduction in symptoms and histopathology, although individuals varied in the magnitude of the response. The mechanism of inhibition of disease is not known, although the results suggest that it could be more complex than the competitive inhibition of ligand binding that is observed in vitro. The demonstration of the beneficial effects of an MCP-1 antagonist in arthritis suggests that chemokine receptor antagonists could have therapeutic application in inflammatory diseases.

Immune response to recombinant mycobacterial proteins in patients with tuberculosis infection and disease

The capacity of four Mycobacterium tuberculosis recombinant antigens to elicit proliferation and cytokine production by human T cells was evaluated. Proliferative responses of peripheral blood mononuclear cells (PBMC) to all antigens were greater in healthy tuberculin reactors than in pulmonary tuberculosis patients, and proliferative responses of pleural fluid cells were greater than those of PBMC from patients with tuberculous pleuritis. The proliferative responses to the four recombinant antigens were similar in all patient groups, and there was no selective unresponsiveness to any antigen in pulmonary tuberculosis patients. The 38-kDa antigen induced less interferon-gamma than did the 10-, 30-, and 65-kDa antigens, and all four antigens induced similar amounts of interleukin-10. These results suggest that none of the four recombinant antigens are immunodominant, and that the 10-, 30-, and 65-kDa antigens are similar in their capacity to induce a potentially protective Th1-like response.

RANTES and MCP-3 antagonists bind multiple chemokine receptors

Antagonists of multiple chemokines could be more effective than inhibitors of specific chemokines for controlling cell migration and inflammation. To attempt to identify such antagonists we characterized a number of truncated analogs of regulated on activation normal T cell expressed protein (RANTES), monocyte chemoattractant protein (MCP)-3, and MCP-1. On the basis of their ability to compete for binding of their parent chemokines, three analogs were selected for cross-reactivity studies: RANTES (9-68), MCP-3 (10-76), and MCP-1 (9-76). These analogs bound to THP-1 monocytic cells with dissociation constants that were within 4-6-fold of their native counterparts, but they did not promote detectable chemotaxis of THP-1 cells or enzyme release from purified human monocytes. The RANTES (9-68) analog competed for the binding and inhibited the activities of all three chemokines. In contrast, native RANTES was specific for RANTES binding sites. However, truncation of either MCP-1 or MCP-3 did not change their respective binding specificity. MCP-3 and MCP-3 (10-76) competed for binding of all three labeled chemokines. MCP-1 (9-76) competed strongly for binding of labeled MCP-1, but only weakly for the other two labeled ligands and inhibited the activities induced by MCP-1 and MCP-3 but not RANTES. Although RANTES (9-68) and MCP-3 (10-76) inhibited all three chemokines, the RANTES analog was significantly more potent for RANTES-induced activity. The results indicate that NH2-terminal residues partly determine the receptor specificity of RANTES, and deletions within this region permit binding to multiple chemokine receptors. The findings suggest the feasibility of design of high affinity multi-specific CC chemokine antagonists.

Interleukin-10 downregulates Mycobacterium tuberculosis-induced Th1 responses and CTLA-4 expression

To characterize the mechanism by which interleukin 10 (IL-10) inhibits Th1 responses to intracellular pathogens, we evaluated the interaction between IL-10 and Mycobacterium tuberculosis-induced gamma interferon (IFN-gamma) production by peripheral blood mononuclear cells from persons across the spectrum of tuberculous infection. M. tuberculosis-induced IFN-gamma production was highest in healthy tuberculin reactors, intermediate in human immunodeficiency virus (HIV)-negative tuberculosis patients, and lowest in HIV-infected tuberculosis patients. Neutralizing antibodies to IL-10 increased IFN-gamma production in HIV-infected and HIV-negative tuberculosis patients by enhancing monocyte IL-12 production. Expression of the T-cell-costimulatory molecule CTLA-4 was depressed in M. tuberculosis-stimulated peripheral blood mononuclear cells from tuberculosis patients, and anti-IL-10 and Il-12 upregulated expression of CTLA-4. These findings provide evidence that intracellular pathogens can inhibit Th1 responses and downregulate expression of specific costimulatory molecules.

Structure-activity relationships of chemokines

Structural analysis of chemokines has revealed that the alpha/beta structural-fold is highly conserved among both the CXC and CC chemokine classes. Although dimerization and aggregation is often observed, the chemokines function as monomers. The critical receptor binding regions are in the NH2-terminal 20 residues of the protein and are the least ordered in solution. The flexible NH2-terminal region is the most critical receptor binding site and a second site also exists in the loop that follows the two disulfides. The well-ordered regions are not directly involved in receptor binding but, along with the disulfides, they provide a scaffold that determines the conformation of the sites that are critical for receptor binding. These general requirements for function are common to all the chemokines. For the CC chemokines, receptor activation and receptor binding regions are separate within the 10 residue NH2-terminal region. This has allowed identification of high affinity analogs that do not activate the receptor and are potent antagonists.

Antagonists of monocyte chemoattractant protein 1 identified by modification of functionally critical NH2-terminal residues

Monocyte chemoattractant protein (MCP)-1 analogues were designed to determine the role of the NH2-terminal region in structure and function. The NH2-terminal residue was important for function and receptor binding, as it could not be deleted or extended. However the NH2-terminal pyroglutamate residue of the wild type was not essential as it could be replaced by several other noncyclic amino acids without loss of activity. Residues 7-10 were essential for receptor desensitization, but were not sufficient for function, and the integrity of residues 1-6 were required for functional activity. A peptide corresponding to MCP-1, 1-10 lacked detectable receptor-binding activities, indicating that residues 1-10 are essential for MCP-1 function, but that other residues are also involved. Several truncated analogues, including 8-76, 9-76, and 10-76, desensitized MCP-1-induced Ca2+ induction, but were not significantly active. These analogues were antagonists of MCP-1 activity with the most potent being the 9-76 analogue (IC50 = 20 nM) The 9-76 specifically bound to MCP-1 receptors with a Kd of 8.3 nM, which was three-fold higher than MCP-1 (Kd 2.8 nM). The 9-76 analogue desensitized the Ca2+ response to MCP-1 and MCP-3, but not to other CC chemokines, suggesting that it is MCP receptor specific. The availability of these compounds will be helpful in evaluating MCP receptor antagonists as anti-inflammatory therapeutics.

Saturation diving with heliox to 350 meters. Observation on hearing threshold, brainstem evoked response and acoustic impedance

Four divers were compressed to 350 m to observe changes in hearing threshold, brainstem evoked response and acoustic impedance. The divers experienced no tinnitus, impairment of hearing, earache during compression. Examination showed that the threshold of lower frequency range of hearing was elevated because of the masking effect of the noise in the hyperbaric chamber. Changes in waveform and latency of brainstem evoked response were due to changes in sound wave transmission affected by the chamber pressure and a poor ratio of signal to noise in the hyperbaric environment with heliox. All these changes were transient. After leaving the chamber, the hearing threshold and brainstem evoked response returned to normal. Besides, there were no changes in tympanogram, acoustic compliance and stapedius reflex before and after diving. This indicated the designed speed of compression and decompression in the experiment caused no damage to the divers' acoustic system, and the functions of their Eustachain tubes, middle and inner ears were normal during the diving test.

Characterization of a human cell line (NK-92) with phenotypical and functional characteristics of activated natural killer cells

The cell line described here was established for a 50-year-old male patient with rapidly progressive non-Hodgkin's lymphoma whose marrow was diffusely infiltrated with large granular lymphocytes (LGL). Immunophenotyping of marrow blasts and peripheral lymphocytes was positive for CD56, CD2 and CD7, and negative for CD3. Cytotoxicity of peripheral blood mononuclear cells at an effector: target (E:T) cell ratio of 50:1 was 79% against K562 cells and 48% against Daudi cells. To establish the line, cells from the peripheral blood were placed into enriched alpha medium containing 12.5% fetal calf serum, 12.5% horse serum, 10(-4) M beta-mercaptoethanol and 10(-6) M hydrocortisone. Growth of the line (termed NK-92) is dependent on the presence of recombinant IL-2 and a dose as low as 10 U/ml is sufficient to maintain proliferation. Conversely, cells die within 72 h when deprived of IL-2; IL-7 and IL-12 do not maintain long-term growth, although IL-7 induces short-term proliferation measured by 3H-thymidine incorporation. None of the other cytokines tested (IL-1 alpha, IL-6, TNF-alpha, IFN-alpha, IFN-gamma) supported growth of NK-92 cells which have the following characteristics: surface marker positive for CD2, CD7, CD11a, CD28, CD45, CD54, CD56bright; surface marker negative for CD1, CD3, CD4, CD5, CD8, CD10, CD14, CD16, CD19, CD20, CD23, CD34, HLA-DR. DNA analysis showed germline configuration for T-cell receptor beta and gamma genes. CD25 (p55 IL-2 receptor) is expressed on about 50% of all cells when tested at 100 U/ml of IL-2 and its expression correlates inversely with the IL-2 concentration. The p75 IL-2 receptor is expressed on about half of the cells at low density irrespective of the IL-2 concentration. NK-92 cells kill both K562 and Daudi cells very effectively in a 4 h51-chromium release assay (84 and 86% respectively, at an E:T cell ratio of 5:1). The cell line described here thus displays characteristics of activated NK-cells and could be a valuable tool to study their biology.

[Pulmonary lymphangiomyomatosis: report of a case]

A case of pulmonary lymphangiomyomatosis in a 28-year-old woman with dyspnea, hemoptysis, chylothorax and irregular menstruation as presenting symptoms was reported. Chest CT scan showed the presence of pleural effusion on right side and a honeycomb pattern throughout the lung parenchyma bilaterally. The diagnosis was confirmed histologically by transbronchial lung biopsy. Medroxyprogesterone was administered; improvement in arterial blood gas analysis and reduction of the amount of pleural effusion were noted after one month. The etiology, clinical manifestations, pathological characteristics and treatment of this disease were discussed.

The potentiating effect of LPS on tumor necrosis factor-alpha production by influenza A virus-infected macrophages

Infection of murine PU5-1.8 macrophages and human monocytes by influenza A virus was associated with virus replication, release of tumor necrosis factor-alpha (TNF-alpha) and subsequent cell death. In the presence of small and by itself rather inefficient concentrations of lipopolysaccharide (LPS) or free lipid A (1 to 10 ng/ml), TNF-alpha production of virus-infected macrophages was strongly potentiated. LPS-triggered and enhanced TNF-alpha release from virus-infected macrophages was neither due to increased cell survival nor altered virus replication, potentiated TNF-alpha gene transcription, release of intracellularly stored TNF-alpha or shifts in the kinetics of TNF-alpha secretion. Influenza A virus infection alone induced a massive TNF-alpha mRNA accumulation which, however, was only weakly translated into bioactive TNF-alpha protein. When these virus-primed macrophages were exposed to LPS either simultaneously or up to 4 h after infection, an efficient and high translation into TNF-alpha protein occurred. Although the LPS-induced biochemical pathways leading to an augmented TNF-alpha production by virus-infected macrophages still remains unsolved, the findings suggest that the frequently observed serious clinical complications in the course of combined influenza A virus and bacterial infections may be due, at least in part, to an excessive release of cytokines such as TNF-alpha.

Cochlear degeneration in guinea pigs after repeated hyperbaric exposures

The effects of repeated hyperbaric exposures on inner ear function and morphology in guinea pigs were investigated with auditory electrophysiological testing, histopathological and electron microscopic techniques associated with enzyme histochemical method. The results showed that repeated hyperbaric exposures, though considered "safe," did cause damage to the cochlear system. Possible causes of the pathology include direct effects of repeated compression and decompression on the ear, and the possibility of inner ear decompression sickness and barotrauma cannot be excluded.

[Preterm delivery and its risk factors]

A case-control study on preterm delivery was conducted in Jianan and Jianhan District, Wuhan City in 1988. 130 singleton preterm infants were included with 260 term infants as control. The results showed that the risk factors in prematurity were edema-proteinuria-hypertension syndrome (OR 1.8), maternal diseases in pregnancy (OR 1.6), hyperemesis gravidarum (OR 5.1), vaginal bleeding during pregnancy (OR 2.4), premature rupture of membranes (OR 3.6), low weight gain and low average weight gain per week during pregnancy, psychosocial stress during pregnancy, inadequate prenatal care, maternal stature less than 158 cm (OR 1.7), menarche before age 12 (OR 4.3), multi-gravida (OR 2.1), previous induced abortion (OR 2.1) and passive cigarette smoking during pregnancy. The author suggests that early treatment of complications of pregnancy and forcing prenatal care should be emphasized in order to reduce the incidence of preterm births.

Influenza A virus infection of macrophages. Enhanced tumor necrosis factor-alpha (TNF-alpha) gene expression and lipopolysaccharide-triggered TNF-alpha release

We have previously shown that infection of macrophages by influenza A virus is capable of priming for a high TNF-alpha production in response to LPS. The present study was designed to examine in more detail TNF-alpha gene expression and TNF-alpha protein release of virus-infected, murine PU5-1.8 macrophages in the presence or absence of low and by itself rather inefficient concentrations of LPS (10 ng/ml). Although influenza A virus infection alone induced a massive TNF-alpha mRNA accumulation, translation into the bioactive TNF-alpha protein was low as intra- and extracellularly determined by bioassay, specific ELISA and Western blot. However, when LPS was added simultaneously or up to 4 h after infection, a high TNF-alpha production was initiated. The virus-induced TNF-alpha mRNA accumulation appeared to be due to both transcriptional and post-transcriptional changes: an enhanced TNF-alpha gene transcription as determined by nuclear run-on transcription assay and a markedly prolonged half-life of TNF-alpha mRNA as shown in actinomycin D-treated macrophages. These findings imply that influenza A virus may 1) either directly or indirectly stimulate TNF-alpha gene transcription activators or may interfere with labile transcription repressor proteins and 2) may stabilize TNF-alpha mRNA by delaying its degradation. Both mechanisms, taken together, prime influenza A virus-infected macrophages for a high TNF-alpha release in response to LPS which, as clinical cases show, may adversely affect patients with combined influenza A virus and bacterial infections.

Influenza A virus infection of macrophages. Enhanced tumor necrosis factor-alpha (TNF-alpha) gene expression and lipopolysaccharide-triggered TNF-alpha release

We have previously shown that infection of macrophages by influenza A virus is capable of priming for a high TNF-alpha production in response to LPS. The present study was designed to examine in more detail TNF-alpha gene expression and TNF-alpha protein release of virus-infected, murine PU5-1.8 macrophages in the presence or absence of low and by itself rather inefficient concentrations of LPS (10 ng/ml). Although influenza A virus infection alone induced a massive TNF-alpha mRNA accumulation, translation into the bioactive TNF-alpha protein was low as intra- and extracellularly determined by bioassay, specific ELISA and Western blot. However, when LPS was added simultaneously or up to 4 h after infection, a high TNF-alpha production was initiated. The virus-induced TNF-alpha mRNA accumulation appeared to be due to both transcriptional and post-transcriptional changes: an enhanced TNF-alpha gene transcription as determined by nuclear run-on transcription assay and a markedly prolonged half-life of TNF-alpha mRNA as shown in actinomycin D-treated macrophages. These findings imply that influenza A virus may 1) either directly or indirectly stimulate TNF-alpha gene transcription activators or may interfere with labile transcription repressor proteins and 2) may stabilize TNF-alpha mRNA by delaying its degradation. Both mechanisms, taken together, prime influenza A virus-infected macrophages for a high TNF-alpha release in response to LPS which, as clinical cases show, may adversely affect patients with combined influenza A virus and bacterial infections.

Influenza A virus infects macrophages and stimulates release of tumor necrosis factor-alpha

The clinical picture of influenza A virus infections indicates that release of tumor necrosis factor-alpha (TNF-alpha) may be involved. In the present study we exposed the murine macrophage line PU5-1.8 to influenza A virus and observed a productive infection which was followed by subsequent cell death. Infection of macrophages was accompanied by TNF-alpha mRNA accumulation and TNF-alpha release. TNF-alpha production could only be induced by live virus whereas interferon release was also stimulated by inactivated virus. When virus-infected macrophages were exposed to low amounts of lipopolysaccharide (LPS; 1-10 ng/ml) TNF-alpha production was strongly potentiated. These data show that low LPS concentrations could readily trigger a high TNF-alpha release from influenza-A-virus-infected macrophages which could, at least partially, explain the serious complications of combined influenza A virus and bacterial infections.

Enhancement of tumor necrosis factor-alpha gene expression by low doses of prostaglandin E2 and cyclic GMP

Macrophage-derived PGE2 is usually considered to be a down-regulator of TNF-alpha production. However, we recently demonstrated that PGE2 may display dual activities in that low concentrations stimulated whereas higher doses suppressed TNF-alpha synthesis in resident peritoneal macrophages. To examine the underlying molecular mechanisms, we studied TNF-alpha gene expression in rat peritoneal macrophages and the murine PU5-1.8 macrophage line. In both macrophage types, PGE2 enhanced TNF-alpha gene transcription and production at an optimal concentration of 1 ng/ml. Furthermore, evidence was obtained that PGE2 may stimulate TNF-alpha mRNA accumulation via a rise of the intracellular messenger cGMP. Both, exogenously added as well as endogenously, by sodium nitroprusside generated cGMP were found to enhance TNF-alpha gene expression and production. These findings lend further support to the concept that cGMP may represent one of the positive signals for TNF-alpha synthesis.

Tumor necrosis factor-alpha production of influenza A virus-infected macrophages and potentiating effect of lipopolysaccharides

Influenza A virus infections are commonly associated with symptoms that suggest involvement of TNF-alpha. In this study, we exposed human monocytes, rat alveolar macrophages, and murine PU5-1.8 macrophages to influenza A virus, strain Puerto Rico 8. We observed a productive infection that was accompanied by TNF-alpha mRNA accumulation, TNF-alpha release and subsequent cell death. TNF-alpha production was dependent on exposure to live virus, in contrast to IFN release that was also induced by UV-inactivated virus. Most strikingly, low amounts of LPS (1 to 10 ng/ml) from Escherichia coli or Haemophilus influenzae were capable of strongly potentiating TNF-alpha production from virus-infected macrophages. The potentiating effect of LPS was neither due to increased survival of macrophages nor to altered virus multiplication, enhanced TNF-alpha gene expression, discharge of intracellular TNF-alpha stores, or shifts in the kinetics of TNF-alpha release. Thus, low amounts of LPS, which could easily be present in vivo, may serve as a potent trigger signal for TNF-alpha production from macrophages that have been primed by influenza A virus infection. These data suggest that the frequently observed serious complications of combined influenza A virus and bacterial infections may be partially due to a high TNF-alpha production.

Tumor necrosis factor-alpha production of influenza A virus-infected macrophages and potentiating effect of lipopolysaccharides

Influenza A virus infections are commonly associated with symptoms that suggest involvement of TNF-alpha. In this study, we exposed human monocytes, rat alveolar macrophages, and murine PU5-1.8 macrophages to influenza A virus, strain Puerto Rico 8. We observed a productive infection that was accompanied by TNF-alpha mRNA accumulation, TNF-alpha release and subsequent cell death. TNF-alpha production was dependent on exposure to live virus, in contrast to IFN release that was also induced by UV-inactivated virus. Most strikingly, low amounts of LPS (1 to 10 ng/ml) from Escherichia coli or Haemophilus influenzae were capable of strongly potentiating TNF-alpha production from virus-infected macrophages. The potentiating effect of LPS was neither due to increased survival of macrophages nor to altered virus multiplication, enhanced TNF-alpha gene expression, discharge of intracellular TNF-alpha stores, or shifts in the kinetics of TNF-alpha release. Thus, low amounts of LPS, which could easily be present in vivo, may serve as a potent trigger signal for TNF-alpha production from macrophages that have been primed by influenza A virus infection. These data suggest that the frequently observed serious complications of combined influenza A virus and bacterial infections may be partially due to a high TNF-alpha production.

Macrophage activation by granulocyte/macrophage colony-stimulating factor. Priming for enhanced release of tumor necrosis factor-alpha and prostaglandin E2

The macrophage-activating properties of murine recombinant granulocyte-macrophage (GM)-CSF were studied in murine peritoneal macrophages with respect to metabolism, endocytosis, PGE2 and TNF-alpha release, and tumor cytotoxicity. GM-CSF was found to be a potent stimulus for RNA and protein synthesis, glucose consumption, pinocytosis, and FcR-independent phagocytosis. Macrophages were activated by GM-CSF to kill TNF-alpha-insensitive Eb lymphoma cells but failed to generate cytotoxicity against TNF-alpha-sensitive L929 cells. Although GM-CSF alone was incapable of stimulating TNF-alpha release, it primed macrophages for elevated TNF-alpha production in response to IFN-gamma plus LPS. The priming effect of GM-CSF disappeared upon longer incubation (greater than 12 h) and was followed by a strongly reduced responsiveness to stimuli that release TNF-alpha. Late-stage suppression could be reverted by treatment with the cyclooxygenase blocker indomethacin, and GM-CSF-induced priming for enhanced TNF-alpha release was entirely restored. The responsible arachidonic acid product mediating suppression was found to be PGE2, because 1) GM-CSF-primed macrophages released enhanced amounts of PGE2 and 2) indomethacin-restored macrophages were again suppressed when exogenous PGE2 was added back in amounts produced by GM-CSF-primed macrophages. Although GM-CSF potently induced TNF-alpha gene transcription by 20 h of treatment, PGE2 interfered with translation into the secreted TNF-alpha protein. These data show that GM-CSF is capable of priming for the enhanced release of two factors, initially for TNF-alpha and subsequently for PGE2. The temporally delayed generation of these two mediators suggests an autoregulatory circuit in which the later produced PGE2 limits GM-CSF-induced macrophage activation.

Macrophage activation by granulocyte/macrophage colony-stimulating factor. Priming for enhanced release of tumor necrosis factor-alpha and prostaglandin E2

The macrophage-activating properties of murine recombinant granulocyte-macrophage (GM)-CSF were studied in murine peritoneal macrophages with respect to metabolism, endocytosis, PGE2 and TNF-alpha release, and tumor cytotoxicity. GM-CSF was found to be a potent stimulus for RNA and protein synthesis, glucose consumption, pinocytosis, and FcR-independent phagocytosis. Macrophages were activated by GM-CSF to kill TNF-alpha-insensitive Eb lymphoma cells but failed to generate cytotoxicity against TNF-alpha-sensitive L929 cells. Although GM-CSF alone was incapable of stimulating TNF-alpha release, it primed macrophages for elevated TNF-alpha production in response to IFN-gamma plus LPS. The priming effect of GM-CSF disappeared upon longer incubation (greater than 12 h) and was followed by a strongly reduced responsiveness to stimuli that release TNF-alpha. Late-stage suppression could be reverted by treatment with the cyclooxygenase blocker indomethacin, and GM-CSF-induced priming for enhanced TNF-alpha release was entirely restored. The responsible arachidonic acid product mediating suppression was found to be PGE2, because 1) GM-CSF-primed macrophages released enhanced amounts of PGE2 and 2) indomethacin-restored macrophages were again suppressed when exogenous PGE2 was added back in amounts produced by GM-CSF-primed macrophages. Although GM-CSF potently induced TNF-alpha gene transcription by 20 h of treatment, PGE2 interfered with translation into the secreted TNF-alpha protein. These data show that GM-CSF is capable of priming for the enhanced release of two factors, initially for TNF-alpha and subsequently for PGE2. The temporally delayed generation of these two mediators suggests an autoregulatory circuit in which the later produced PGE2 limits GM-CSF-induced macrophage activation.

Molecular cloning and expression in Escherichia coli of a cellodextrinase gene from Bacteroides succinogenes S85

A DNA fragment coding for a cellodextrinase of Bacteroides succinogenes S85 was isolated by screening of a pBR322 gene library in Escherichia coli HB101. Of 100,000 colonies screened on a complex medium with methylumbelliferyl-beta-D-cellobioside as the indicator substrate, two cellodextrinase-positive clones (CB1 and CB2) were isolated. The DNA inserts from the two recombinant plasmids were 7.7 kilobase pairs in size and had similar restriction maps. After subcloning from pCB2, a 2.5-kilobase-pair insert which coded for cellodextrinase activity was isolated. The enzyme was located in the cytoplasm of the E. coli host. It exhibited no activity on carboxymethyl cellulose, Avicel microcrystalline cellulose, acid-swollen cellulose, or cellobiose but hydrolyzed p-nitrophenyl-beta-D-cellobioside and p-nitrophenyl-beta-D-lactoside. The Km (0.1 mM) for the hydrolysis of p-nitrophenyl-cellobioside by the enzyme expressed in E. coli was similar to that reported for the purified enzyme from B. succinogenes. Expression of the cellodextrinase gene was subjected to catabolite repression by glucose and was not induced by cellobiose. The origin of the DNA insert from B. succinogenes was confirmed by Southern blot analysis. Western blotting (immunoblotting) using antibodies raised against the purified B. succinogenes cellodextrinase revealed a protein with a molecular weight of approximately 50,000 in E. coli clones which comigrated with the native enzyme isolated from B. succinogenes. These data indicate that the cellodextrinase gene expressed in E. coli is fully functional and codes for an enzyme with properties similar to those of the native enzyme.

Release of tumor necrosis factor-alpha from macrophages. Enhancement and suppression are dose-dependently regulated by prostaglandin E2 and cyclic nucleotides

PGE2 has previously been shown to suppress various leukocyte functions. In this study, we examined whether PGE2 would affect release of TNF-alpha from rat resident peritoneal macrophages. Two different, dose-dependent effects were observed: low PGE2 concentrations (0.1 to 10 ng/ml) stimulated, whereas higher concentrations (greater than 10 ng/ml) suppressed TNF-alpha release. PGE2-stimulated TNF-alpha production was dependent on de novo protein synthesis and was associated with an intracellular rise of cGMP. The importance of cGMP as an intracellular messenger for PGE2 was confirmed by the following evidence: (1) low PGE2 concentrations preferentially increased cGMP and not cAMP and (2) cGMP, either exogenously added or endogenously generated by sodium nitroprusside, were efficient stimulators of TNF-alpha production. In contrast, agents increasing intracellular cAMP concentrations such as PGE1, higher PGE2 doses, isoproterenol, and theophylline, all suppressed TNF-alpha synthesis. Only resident, but not casein-elicited or Corynebacterium parvum-activated macrophages, were stimulated by low PGE2 concentrations to increase TNF-alpha production. In tumor cytotoxicity assays, PGE2-activated macrophages were active only against TNF-alpha-sensitive target cells. These findings demonstrate that TNF-alpha synthesis in macrophages is up-regulated by cGMP and down-regulated by cAMP, which indicates that cyclic nucleotides act as intracellular messengers for extracellular signals of macrophage activation.

Release of tumor necrosis factor-alpha from macrophages. Enhancement and suppression are dose-dependently regulated by prostaglandin E2 and cyclic nucleotides

PGE2 has previously been shown to suppress various leukocyte functions. In this study, we examined whether PGE2 would affect release of TNF-alpha from rat resident peritoneal macrophages. Two different, dose-dependent effects were observed: low PGE2 concentrations (0.1 to 10 ng/ml) stimulated, whereas higher concentrations (greater than 10 ng/ml) suppressed TNF-alpha release. PGE2-stimulated TNF-alpha production was dependent on de novo protein synthesis and was associated with an intracellular rise of cGMP. The importance of cGMP as an intracellular messenger for PGE2 was confirmed by the following evidence: (1) low PGE2 concentrations preferentially increased cGMP and not cAMP and (2) cGMP, either exogenously added or endogenously generated by sodium nitroprusside, were efficient stimulators of TNF-alpha production. In contrast, agents increasing intracellular cAMP concentrations such as PGE1, higher PGE2 doses, isoproterenol, and theophylline, all suppressed TNF-alpha synthesis. Only resident, but not casein-elicited or Corynebacterium parvum-activated macrophages, were stimulated by low PGE2 concentrations to increase TNF-alpha production. In tumor cytotoxicity assays, PGE2-activated macrophages were active only against TNF-alpha-sensitive target cells. These findings demonstrate that TNF-alpha synthesis in macrophages is up-regulated by cGMP and down-regulated by cAMP, which indicates that cyclic nucleotides act as intracellular messengers for extracellular signals of macrophage activation.

Interleukin 1 as a tumor cytostatic mediator released from tumor ascites-treated macrophages

Peritoneal macrophages from DBA/2 mice, elicited by injection of Corynebacterium parvum (C.p.), were in vitro activated to Eb tumor cytostasis by incubation with tumor-induced ascites that was harvested 7 days after intraperitoneal Eb injection. The active cytostasis-mediating compound was found to be interleukin 1 (IL 1). When tumor ascites was fractionated according to molecular weight size, the most active IL 1-inducing fraction was found to comprise molecules of greater than 100,000 daltons. The data show that tumor-bearing hosts are capable of producing compounds that induce a high IL 1 secretion which may enable macrophages to mount an antiproliferative effect against tumor cells.

Reduction of macrophage-mediated tumor cytotoxicity by pretreatment with GM-CSF

The effect of granulocyte/macrophage colony stimulating factor (GM-CSF) on macrophage activation by interferon-gamma (IFN-gamma) plus lipopolysaccharide (LPS) was studied in a murine model system. When peritoneal macrophages were pretreated with GM-CSF for 24 hrs, a strong reduction of IFN-gamma-induced tumor cytotoxicity and LPS-triggered tumor necrosis factor-alpha (TNF-alpha) release was found. In contrast, GM-CSF treatment of macrophages for only 4 to 8 hrs enhanced TNF-alpha production. These data suggest that GM-CSF may affect macrophage activation in a biphasic manner in that a time period of enhanced responsiveness to IFN-gamma is followed by a longlasting period of refractoriness.

Potentiation of lymphokine-induced macrophage activation by tumor necrosis factor-alpha

In this study, we examined the possible role of TNF-alpha and lymphotoxin (TNF-beta) as cofactors of macrophage activation. The results demonstrate that both TNF were capable of enhancing the cytostatic and cytolytic activity of murine peritoneal macrophages against Eb lymphoma cells. The potentiation of tumor cytotoxicity became apparent when macrophages from DBA/2 mice were suboptimally activated by either a T cell clone-derived macrophage-activating factor or by IFN-gamma plus LPS. Neither TNF-alpha nor TNF-beta could induce tumor cytotoxicity in IFN-gamma-primed macrophages, indicating that TNF cannot replace LPS as a triggering signal of activation. In LPS-resistant C3H/HeJ macrophages, which were unresponsive to IFN-gamma plus LPS, a supplementation with TNF fully restored activation to tumor cytotoxicity. Furthermore, TNF-alpha potentiated a variety of other functions in low-level activated macrophages such as a lactate production and release of cytotoxic factors. At the same time, TNF-alpha produced a further down-regulation of pinocytosis, tumor cell binding and RNA synthesis observed in activated macrophages. These data demonstrate new activities for both TNF-alpha and TNF-beta as helper factors that facilitate macrophage activation. In particular, the macrophage product TNF-alpha may serve as an autocrine signal to potentiate those macrophage functions that were insufficiently activated by lymphokines.

Potentiation of lymphokine-induced macrophage activation by tumor necrosis factor-alpha

In this study, we examined the possible role of TNF-alpha and lymphotoxin (TNF-beta) as cofactors of macrophage activation. The results demonstrate that both TNF were capable of enhancing the cytostatic and cytolytic activity of murine peritoneal macrophages against Eb lymphoma cells. The potentiation of tumor cytotoxicity became apparent when macrophages from DBA/2 mice were suboptimally activated by either a T cell clone-derived macrophage-activating factor or by IFN-gamma plus LPS. Neither TNF-alpha nor TNF-beta could induce tumor cytotoxicity in IFN-gamma-primed macrophages, indicating that TNF cannot replace LPS as a triggering signal of activation. In LPS-resistant C3H/HeJ macrophages, which were unresponsive to IFN-gamma plus LPS, a supplementation with TNF fully restored activation to tumor cytotoxicity. Furthermore, TNF-alpha potentiated a variety of other functions in low-level activated macrophages such as a lactate production and release of cytotoxic factors. At the same time, TNF-alpha produced a further down-regulation of pinocytosis, tumor cell binding and RNA synthesis observed in activated macrophages. These data demonstrate new activities for both TNF-alpha and TNF-beta as helper factors that facilitate macrophage activation. In particular, the macrophage product TNF-alpha may serve as an autocrine signal to potentiate those macrophage functions that were insufficiently activated by lymphokines.