Detection of monocyte chemotactic and activating factor (MCAF) in normal blood and urine using a sensitive ELISA

Preparation of a superantigen-adsorbing device and its superantigen removal efficacies in vitro and in vivo

OBJECTIVE

A new superantigen-adsorbing device (SAAD) was developed, and its characteristics and efficacy in septic animals were evaluated.

METHODS

The SAAD was prepared by stepwise chemical modification of a polystyrene-based composite fiber reinforced with polypropylene. Adsorption affinities for several factors and the biological effect of superantigen (SAg) removal were measured in vitro. Also, superantigen-infused rabbits were treated with SAAD, and the efficacy was evaluated in vivo.

RESULTS

When the SAAD was evaluated for its ability to adsorb SAg in human plasma (1 ng/mL each), the adsorption rates were 74%, 76% and 85% for staphylococcal enterotoxins A, B and C, respectively, and 80% and 72% for toxic shock syndrome toxin-1 (TSST-1) and streptococcal pyrogenic exotoxin A, respectively. In addition, the SAAD showed some affinity towards other molecules, such as streptococcal pyrogenic exotoxin B, beta2-microglobulin, and vancomycin. Residual activities in whole blood samples containing TSST-1 (1 ng/mL) after incubation with the SAAD were 125 pg/mL for tumor necrosis factor alpha (TNF-alpha) production, and 359 pg/mL for interleukin-8 (IL-8) production (the initial activities: 194 pg/mL for TNF-alpha production, and 1029 pg/mL for IL-8 production). When TSST-1/lipopolysaccharide (LPS)-infused rabbits were subjected to extracorporeal blood purification with a SAAD column, 50% of the animals survived for a 14-day period after the infusion. In contrast, all control animals died within 3 days after the infusion.

CONCLUSION

These results indicate that the SAg-adsorbing device may be useful in treating SAg-related diseases.

Monocyte chemoattractant protein 1 (MCP-1) in temporal arteritis and polymyalgia rheumatica

OBJECTIVE

To examine the localisation of monocyte chemoattractant protein 1 (MCP-1) in the inflamed vessel wall in temporal arteritis (TA) and to measure MCP-1 in plasma both in patients with TA and patients with polymyalgia rheumatica (PMR).

METHODS

By immunohistochemical techniques MCP-1 was localised to the vessel wall in patients with TA. In TA, PMR, and healthy controls MCP-1 was quantified by enzyme linked immunosorbent assay (ELISA) in plasma.

RESULTS

MCP-1 was localised to the majority of mononuclear cells, some smooth muscle cells, and giant cells in the arterial biopsy specimens from 12 patients with histologically verified TA. In all sections, including the vasa vasorum, the endothelium stained positive. In the intima 73% (range 57-91%), in the media 49% (range 32-67%), and in the adventitia 74% (range of 62-91%) of all cells stained positive. In plasma MCP-1 was significantly raised in untreated TA (n=33) and untreated PMR (n=27) compared with healthy controls (n=12). Untreated TA plasma levels of MCP-1 (mean 391 pg/ml (range 82-778 pg/ml)) were similar to untreated PMR plasma levels (mean 402 pg/ml (range 29-1153 pg/ml)), and no significant difference was found between the two groups of patients. In both patients with TA and patients with PMR no correlation was found between the plasma level of MCP-1 and the erythrocyte sedimentation rate, haemoglobin concentration, and CD4/CD8 ratio.

CONCLUSIONS

These results show that MCP-1 plays a part in the disease processes of TA and PMR.

Induction of monocyte chemoattractant protein-1 (MCP-1) production by Pseudomonas nitrite reductase in human pulmonary type II epithelial-like cells

Monocyte chemoattractant protein-1 (MCP-1), a chemoattractant for monocytes, is presumed to play a pivotal role in the recruitment and accumulation of monocytes in various diseases including pulmonary infections. We examined here whether or not Pseudomonas nitrite reductase (PNR), a recently identified IL-8 inducer in various respiratory cells, could stimulate human pulmonary type II epithelial-like cells (A549) to induce MCP-1 production. A time- and dose-dependent induction of MCP-1 protein synthesis associated with an increase of MCP-1 mRNA expression by A549 cells was observed in response to PNR. New protein translation was not required for PNR-mediated MCP-1 mRNA expression in the same cells. When anti-human MCP-1 monoclonal antibody was used for neutralizing of monocyte chemotactic factor (MCF) activities in the culture supernatants of these cells stimulated with PNR, significant reductions of MCF activities (the mean reduction rate; 49-59%, P<0. 05) were observed. These data suggest that PNR may contribute to monocyte migration, through inducing pulmonary epithelial cell-derived MCP-1 production in the airway of patients with pneumonia due to P. aeruginosa.

Glucocorticoids inhibit chemokine generation by human eosinophils

Recent identification of eosinophils as a cellular source of various cytokines suggests that eosinophil-derived cytokines contribute to allergic inflammation through either an autocrine or a paracrine fashion. The profound inhibitory effects of glucocorticoids (GCCs) on the production of various cytokines have been well recognized, however, there has been no definitive evidence that GCCs in fact inhibit cytokine generation by eosinophils. To verify the inhibitory ability of GCCs on eosinophil cytokine generation, we studied the effect of GCCs by determination of IL-8 and monocyte chemoattractant protein-1 (MCP-1) as parameters. Dexamethasone (DEX) inhibited both generation and secretion of IL-8 in a dose-dependent fashion. DEX also dampened formyl-methionyl-leucyl-phenylalanine-or ionomycin-induced eosinophil IL-8 production. Furthermore, MCP-1 production was also inhibited by DEX. The slope and the shape of the dose-response curve of DEX were similar irrespective of either the input stimuli or the output cytokines; half-maximal inhibition was observed at 10(-8) mol/L, and nearly complete abolishment was observed at 10(-7) mol/L. The competitive polymerase chain reaction for IL-8 mRNA and semiquantitative polymerase chain reaction for MCP-1 mRNA revealed that the inhibition occurred at a level of pretranslation. These results indicate that the beneficial effect of GCCs in allergic inflammation might be related, at least in part, to a direct effect of the drugs on eosinophil cytokine synthesis.

The inhibition of synthesis of a beta-chemokine, monocyte chemotactic protein-1 (MCP-1) by progesterone

The control of chemokines in reproductive tissues has not been well characterised. Progesterone plays a major part in many reproductive processes and an interaction between progesterone and the immune system has been postulated. MCP-1 is a beta chemokine that attracts and activates macrophages, controls vascular smooth muscle cells, and can modulate T helper cell cytokine production. MCP-1 may also play a role in reproductive processes such as ovulation and parturition. MCP-1 synthesis is stimulated by the transcription factor NF-kappa B and is inhibited by glucocorticoid but the relevance of progesterone control in reproductive tissue is unknown. The effects of progesterone on the production in both choriodecidual cells and a breast cancer cell line T47D, which expresses an oestrogen insensitive progesterone receptor, were investigated. A synthetic progestin (medroxyprogesterone acetate) inhibits choriodecidual cell production of MCP-1; this inhibition was reversed by the antiprogestin RU486. MCP-1 release from T47D cells can be stimulated by IL-1 and this production is inhibited by progesterone with an ED50 of less than 10(-9) M. A glucocorticoid (dexamethasone) had no effect on MCP-1 release in this system, suggesting that glucocorticoid receptor-mediated responses were impaired under these conditions. These results demonstrate that an indirect effect of progesterone on the immune system is possible in reproductive tissues, whereby the initial effect of progesterone on epithelial or fibroblast cells would be transmitted to leukocytes.

Differential secretion of chemokines from peripheral blood in pregnant compared with non-pregnant women

The maintenance of a normal pregnancy is dependent on the delicate interaction between the endocrine and the immune systems. Cytokines are thought to play a key role in pregnancy by way of local modulation of the immune system at the level of peripheral leukocytes. This study examined the potential of peripheral venous blood cultures from pregnant women throughout gestation and from non-pregnant women to produce the chemokines monocyte chemotactic protein-1 (MCP-1), interleukin-8 (IL-8) and RANTES. Significantly (P = < 0.001), higher levels of MCP-1 were released from peripheral blood cultures from pregnant women at term than during the first trimester or from women who were not pregnant. This could not be accounted for by differences in differential blood counts. Significantly higher levels (P = < 0.05) of MCP-1 were released from PBMC preparations from pregnant compared with non-pregnant women. No 'rebound' increase in MCP-1 was observed on withdrawing progesterone support to the PBMC preparations. MCP-1 was secreted predominately from CD14+ cells with those from pregnant women producing more than those from non-pregnant women. There was no statistical difference in release of IL-8 or RANTES from either peripheral blood or PBMC preparations from pregnant or non-pregnant women. IL-8 and RANTES were secreted from CD14+ and CD14- cells, respectively. The hypothesis proposed is that the monocytes are fundamentally different in pregnancy and that measurement of MCP-1 has the potential to act as a marker of pregnancy status.

A sensitive immunoassay to detect the alpha-chemokine GRO in rabbit blood and lung fluids

GRO-alpha, GRO-beta and GRO-gamma are closely related peptides that stimulate growth of tumor cells and activate leukocytes in acute inflammatory reactions. In order to study the biology of GRO peptides in the lungs of experimental animals, we have developed and characterized a sensitive and specific immunoassay for rabbit GRO, and used this assay to measure GRO in rabbit lung fluids and plasma. GRO was cloned from a rabbit cDNA library and expressed in Escherichia coli. Specific goat polyclonal antibodies were used to create an antigen-capture immunoassay. The assay is sensitive to approximately 30 pg/ml GRO and does not crossreact with rabbit IL-8 or MCP-1, or human GRO. The assay accurately measures GRO in rabbit bronchoalveolar lavage fluid, plasma and serum. Rabbit erythrocytes bind little GRO and do not interfere with the detection of GRO in lung fluids. Circulating GRO was detected in the plasma of 4 of 6 pathogen-free rabbits, but the function of circulating GRO in normal animals is uncertain. This immunoassay will facilitate the study of the biology of GRO in rabbits with acute and chronic inflammation in the lungs and other tissues.

Expression and regulation of monocyte chemoattractant protein-1 by human eosinophils

Several recent studies have identified eosinophils as a cellular source of various cytokines, indicating that eosinophils play not only an effector role, but also a regulatory role within the allergic inflammatory cell network. In this study, we demonstrate that eosinophils can generate and secrete monocyte chemoattractant protein-1 (MCP-1), a prototype of C-C chemokines. Eosinophils generated immunoreactive MCP-1 in response to such diverse stimuli as C5a, formyl-methionyl-leucyl-phenylalanine (FMLP) and ionomycin, but MCP-1 production was not induced by interleukin (IL)-1 or tumor necrosis factor-alpha. C5a- and FMLP-induced eosinophil MCP-1 production was absolutely dependent on pretreatment with cytochalasin B. Eosinophils elaborated significantly more MCP-1 than neutrophils. Immunoreactive MCP-1 was detected at 6 h of incubation with C5a or FMLP. Expression of MCP-1 mRNA reached a maximum within the first 3 h after stimulation and then declined rapidly to a very low and stable level by 18 h. Pretreatment with IL-5 markedly amplified C5a-induced MCP-1 production, and the enhancement occurred at the pretranslational level. Eosinophil-active chemokines such as eotaxin failed to induce MCP-1 generation, even when eosinophils were primed by IL-5. Since MCP-1 exerts a potent histamine-releasing effect on human basophils, our results indicate that eosinophils may regulate basophil mediator release with possible consequent contribution to the pathogenesis of allergic inflammation via a paracrine mechanism.

Sensitive and specific immunoassays to detect rabbit IL-8 and MCP-1: cytokines that mediate leukocyte recruitment to the lungs

The alpha- and beta-chemokines such as IL-8 and MCP-1 direct the recruitment of neutrophils and monocytes into the lungs and other tissues. In order to study the roles of IL-8 and MCP-1 in animals models, specific reagents are required that provide accurate measurements of these cytokines in biological fluids. Here we describe the development of sensitive and specific immunoassays for rabbit IL-8 and rabbit MCP-1, and the validation of these assays in rabbit plasma and bronchoalveolar lavage fluid. The sensitivity of each assay in 0.25 ng/ml for IL-8 and 0.1 ng/ml for MCP-1. The rabbit IL-8 assay does not crossreact with rabbit GRO, another alpha-chemokine, and crossreacts only weakly with human IL-8. The rabbit MCP-1 assay does not crossreact with human MCP-1. Anticoagulants interfere with the detection of IL-8 and MCP-1 in plasma, although. EDTA has the least inhibitory effect. Heat-sensitive inhibitors in normal rabbit serum interfere with the detection of IL-8 and MCP-1, although autoantibodies to IL-8 and MCP-1 were not detected. Rabbit erythrocytes bind IL-8 and MCP-1, but erythrocyte contamination of bronchoalveolar lavage fluid causes only a small error in the detection of IL-8 and MCP-1, unless the number of erythrocytes approaches the number found in blood. These assays provide sensitive and specific means to detect IL-8 and MCP-1 in rabbit plasma and bronchoalveolar lavage fluid, and demonstrate the importance of using species-specific reagents in animal studies.

Detection of monocyte chemotactic and activating factor (MCAF) and interleukin (IL)-6 in human seminal plasma and effect of leukospermia on these cytokine levels

PROBLEM

To demonstrate whether monocyte chemotactic and activating factor (MCAF) and interleukin-6 (IL-6) are present in the seminal plasma, and whether these presence is modulated by leukospermia.

METHODS

Semen samples from 53 men were obtained by masturbation and examined for the presence of MCAF and IL-6 by enzyme immunoassay (EIA). Semen samples were obtained from 28 infertile men without leukospermia, 16 infertile men with leukospermia, and nine proven-fertile men. The correlation between the amount of MCAF in the seminal plasma with some spermiogram parameters and other cytokines such as IL-6 and IL-8 was statistically evaluated.

RESULTS

Immunoreactive MCAF was detected in the seminal plasmas of all 53 subjects. The MCAF titer in the seminal plasma of patients with leukospermia (11.19 +/- 2.75 micrograms/l) was significantly higher than that in the seminal plasma of the patients without leukospermia (3.24 +/- 0.53 micrograms/l) and the fertile men (2.78 +/- 0.35 micrograms/l) (P < 0.001). The IL-6 titer in the seminal plasma of the patients with leukospermia (21.05 +/- 4.49 ng/l) was also significantly higher than that in the seminal plasma of the patients without leukospermia (8.77 +/- 1.92 ng/l) and the fertile men (6.94 +/- 1.27 ng/l) (P < 0.01). There was a high degree of correlation among the levels of MCAF, IL-6 and IL-8 in the seminal plasma.

CONCLUSIONS

These findings demonstrated the presence of MCAF and IL-6 in the seminal plasma, and that the levels of these cytokines were elevated in the seminal plasma of the infertile patients with leukospermia.

Interleukin-8 and monocyte chemotactic activating factor responses to cardiopulmonary bypass

Cardiac operations with cardiopulmonary bypass cause a systemic inflammatory response. Neutrophils and monocytes-macrophages play an important role in triggering the initiation of the inflammatory response. Recently, some kinds of cytokines that are powerful leukocyte chemotactic factors have been characterized concerning an inflammatory response: interleukin-8 has a potent chemoattractant activity for neutrophils, and monocyte chemoattractant factor has monocyte-macrophage chemotactic activity. To investigate the possible roles of the cytokines in the inflammatory response in cardiopulmonary bypass, 12 adult patients undergoing cardiopulmonary bypass were studied for measurement of interleukin-8 and monocyte chemoattractant factor. Systemic blood was collected before cardiopulmonary bypass, at the end of cardiopulmonary bypass, and at 3, 12, 24, and 48 hours after cardiopulmonary bypass from the patients' radial arteries. Significant increases in levels of interleukin-8 and monocyte chemoattractant factor were detected with a peak level at 3 hours after bypass compared with levels before cardiopulmonary bypass (p < 0.05). This study demonstrated that interleukin-8 and monocyte chemoattractant factor are released into the circulation after adult hypothermic cardiopulmonary bypass and reach a maximum level 3 hours after bypass.