Peri-interventional endothelin--a receptor blockade improves long-term outcome in patients with ST-elevation acute myocardial infarction.

Endothelin (ET)-1 is a pro-fibrotic vasoconstrictive peptide causing microvascular dysfunction and cardiac remodelling after acute ST-elevation myocardial infarction (STEMI). It acts via two distinct receptors, ET-A and ET-B, and is involved in inflammation and atherogenesis. Patients with posterior-wall STEMI were randomly assigned to intravenous BQ-123 at 400 nmol/minute (min) or placebo over 60 min, starting immediately prior to primary percutaneous coronary intervention (n=54). Peripheral blood samples were drawn at baseline as well as after 24 hours and 30 days. Myeloperoxidase (MPO), as a marker of neutrophil activation and matrix metalloproteinase 9 (MMP-9), a marker of extracellular matrix degradation were measured in plasma. Clinical follow-up was conducted by an investigator blinded to treatment allocation over three years. During the median follow-up period of 3.6 years (interquartile range [IQR] 3.3-4.1) we observed a longer event-free survival in patients randomised to receive BQ-123 compared with patients randomised to placebo (mean 4.5 years (95% confidence interval: 3.9-5) versus mean 3 years (2.2-3.7), p=0.031). Patients randomised to ET-A receptor blockade demonstrated a greater reduction of MPO levels from baseline to 24 hours compared to placebo-treated patients (-177 ng/ml (IQR 103-274) vs -108 ng/ml (74-147), p=0.006). In addition, a pronounced drop in MMP-9 levels (-568 ng/ml (44-1157) vs -117 ng/ml (57-561), p=0.018) was observed. There was no significant difference in amino-terminal propetide of pro-collagen type III levels. In conclusion, short-term administration of BQ-123 leads to a reduction in MPO, as well as MMP-9 plasma levels and to a longer event-free survival in patients with STEMI.

Inducible nitric oxide synthase and tumor necrosis factor in animal models of myocardial necrosis induced by coronary artery ligation or isoproterenol injection.

BACKGROUND: Increased expression of inducible nitric oxide synthase (iNOS) has been described in humans with cardiomyopathies. Most animal models of ischemia-induced heart failure use the surgical ligation of coronary arteries. However, studies of iNOS expression in these models may be confounded by a robust immune response because of the surgical procedure itself leading to iNOS expression in the heart, as well as in other tissues. METHODS AND RESULTS: iNOS expression was studied in adult male rats injected subcutaneously with either 250 mg/kg of isoproterenol (ISO) or vehicle on 2 consecutive days. This approach induces diffuse myocardial necrosis and leads to the development of a dilated cardiomyopathy. Hearts from ISO-injected animals harvested at 6 weeks had evidence of apical and subendocardial scarring. These hearts showed a 9.6-fold (left ventricle [LV], P = .004) and an 11.9-fold (right ventricle, P = .002) increase in the expression of tumor necrosis factor (TNF), and a 6.8-fold increase (LV, P = .0183) in iNOS messenger RNA compared with vehicle-injected controls. iNOS protein also was detectable by immmunoprecipitation in left ventricular muscle from ISO-injected animals, as well as by immunohistochemical analysis. CONCLUSION: Expression of TNF and iNOS in the heart is increased in an experimental model of dilated cardiomyopathy that minimizes the confounding effects of surgery, supporting a role for the activation of innate immunity signaling pathways in the pathogenesis of heart failure.

Influence of pentoxifylline on cytokine levels and inflammatory parameters in septic shock.

OBJECTIVE: To evaluate the influence of pentoxifylline (PTX), a phosphodiesterase inhibitor, on cytokines and inflammatory proteins in patients suffering from septic shock. DESIGN: Prospective study comparing a therapy group to a matched control group. SETTING: Medical intensive care unit at a university hospital. PATIENTS: Twenty four patients fulfilling the criteria of septic shock were included in this study. Twelve patients received PTX (therapy group) and 12 patients matched for diagnosis, age and gender served as the control group. INTERVENTIONS: Pentoxifylline at 1 mg/kg per hour over 24 h in the therapy group. MEASUREMENTS AND RESULTS: Cytokine levels [tumor necrosis factor-alpha (TNF)], soluble TNF receptor [TNF-R], and interleukin-6 [IL-6] and inflammatory proteins [C-reactive protein, alpha-1-antitrypsin (AAT), fibronectin, and haptoglobin], as well as hemodynamic parameters and the APACHE III score were evaluated before initiation of therapy and 24 h-later. After 24 h, TNF levels were significantly lower in the therapy group (p = 0.013), while IL-6 levels were significantly higher in the therapy group (p = 0.030). Within the 24 h TNF declined significantly in the therapy group (p = 0.006), while IL-6 showed a significant increase (p = 0.043). AAT and the APACHE III score tended to differ significantly after 24 h between the groups [AAT levels higher in the therapy group (p = 0.05), APACHE III score lower (p = 0.05)]. In the therapy group, the systemic vascular resistance index was significantly higher after 24 h (p = 0.0026) whereas the cardiac index declined (p = 0.035). CONCLUSIONS: PTX does influence TNF levels in septic shock patients. Nevertheless, inhibiting a single mediator in severe septic shock cannot stop the inflammatory overreaction.

Differential expression of complement receptors on human basophils and mast cells. Evidence for mast cell heterogeneity and CD88/C5aR expression on skin mast cells.

Complement-dependent activation of immune cells is regulated by cell surface membrane receptors. In this study, expression of complement receptors (CR) on human blood basophils (n = 11), tissue mast cells (lung, n = 7; skin, n = 10; uterus, n = 4; tonsil, n = 3; heart, n = 10), and on respective human cell lines (basophil line KU-812, mast cell line HMC-1) was analyzed by the use of mAbs and indirect immunofluorescence. Normal blood basophils and KU-812 cells were found to express C5aR (CD88), membrane cofactor protein (CD46), decay-accelerating factor (CD55), and membrane attack complex inhibitory factor (CD59), as well as the previously recognized CR1 (CD35), CR3 alpha (CD11b), CR4 alpha (CD11c), and CR3/4 beta (CD18). Mast cells from all organs as well as HMC-1 cells expressed CD46, CD55, and CD59, but not CD11b, CD21, or CD35. The C5aR (CD88) was detectable on skin mast cells, a subset (5 to 15%) of cardiac mast cells, and on HMC-1 cells, but not on lung, uterus, or tonsillar mast cells (< 5%). Moreover, double immunoperoxidase staining (tryptase vs C5aR/CD88) revealed in situ expression of C5aR on skin, but not lung mast cells. Recombinant human (rh) C5a, at 10(-10) to 10(-7) M, induced secretion of histamine from basophils (rhC5a, 10(-8) M: 53.4 +/- 3.1% vs control < 5%) and from skin mast cells (rhC5a, 10(-8) M: 25.8 +/- 16.1% vs control < 10% histamine release), but not from other mast cells (rhC5a or control: < 10%, p > 0.05). The rhC5a-induced secretion of histamine from basophils and skin mast cells was inhibited by S5/1, a blocking Ab against CD88 (basophils: 37.2% to 75.1%; skin mast cells: 39.2% to 83.9% inhibition, p < 0.05). Together, this study shows that a) basophils and mast cells express a different profile of complement receptors, b) C5a-dependent mediator release in skin mast cells and basophils is mediated via CD88, and c) mast cells constitute a heterogeneous lineage in terms of expression of the C5a binding site CD88.

Measuring extracellular matrix turnover in the serum of patients with idiopathic or ischemic dilated cardiomyopathy and impact on diagnosis and prognosis.

Circulating levels of extracellular matrix components were measured by radioimmunoassays and tested if they were useful for clinical staging in chronic heart failure. In 41 patients with dilated cardiomyopathy (33 idiopathic and 8 ischemic cases), the serum concentrations of procollagen type III aminoterminal peptide (PIIINP), type I collagen telopeptide (ICTP), and basement membrane laminin were significantly higher than in 30 healthy controls regardless of the underlying etiology. Patients with serum values of PIIINP, ICTP, and laminin > 7 micrograms/L, 7.6 micrograms/L, and 2.3 U/ml, respectively, were at higher relative risk for advanced clinical stage, poor hemodynamic condition, hyponatremia, heart transplantation, and death during follow-up than patients with low levels, with the exception that serum laminin > 2.3 U/ml was not significantly associated with hyponatremia and heart transplantation. Despite their interdependence on liver function, circulating levels of PIIINP and ICTP were independent predictors of mortality. In 17 of the 41 patients with cardiomyopathy whose explanted hearts were available for histologic evaluation, serum PIIINP, ICTP, and laminin significantly correlated with the myocardial area fractions of their tissue analogues (PIIINP vs myocardial collagen type III, r = 0.784, p = 0.0013; serum ICTP vs myocardial collagen type I, r = 0.603, p = 0.0527; and serum laminin vs myocardial laminin, r = 0.605, p = 0.0411). In conclusion, the increase in extracellular matrix turnover, which may partially be derived from fibrosis in the myocardium, can be measured in the serum of patients with dilated cardiomyopathy, and has an impact on risk stratification and prognosis.

Emergency intubation with the Combitube in two cases of difficult airway management.

The airway was managed successfully in two cases of difficult intubation using the Combitube, a new device for emergency intubation, which combines the functions of an oesophageal obturator airway and a conventional endotracheal airway. One patient could not be intubated due to lockjaw; in the other patient, the vocal cords could not be seen because of continued vomiting. The cases illustrate the benefit of the Combitube during emergency intubation for different problems and its effectiveness as an alternative to traditional intubation techniques.

Increase and redistribution of cardiac mast cells in auricular thrombosis. Possible role of kit ligand.

BACKGROUND: The atrial appendage is a predilection site for thrombus formation. Mast cells (MC) are a rich source of mediators that may be involved in the regulation of thrombus formation. We examined number, distribution, and phenotype of MC in thrombosed versus unaffected auricles to elucidate their possible role in auricular thrombosis (AUTHR). METHODS AND RESULTS: Sections of atrial appendages (AUTHR, n = 14; controls (CO), n = 13) were analyzed for MC by Giemsa, toluidine blue, and berberine sulfate stains and by immunohistochemistry. Cardiac MC expressed CD antigens corresponding to the classic MC phenotype as well as tryptase, chymase, and heparin. Thrombosis was associated with a twofold increase in the number of MC in the total appendage (CO, 3.1 +/- 1.0 versus AUTHR, 6.4 +/- 1.1 MC/mm2, P < .01). Moreover, in AUTHR, a redistribution of MC to the upper endocardium was observed (AUTHR, 5.3 +/- 1.4 versus CO, 0.07 +/- 0.15 MC/mm2, P < .01). Mast cell growth factor (MGF) was expressed in the endothelium and subendothelial space of thrombosed appendages but not in the normal endocardium. Overexpression of MGF was accompanied by a weak or absent expression of the MGF receptor c-kit on redistributed MC in AUTHR. Patients with unilateral atrial appendage thrombosis did not exhibit a MC increase or redistribution in the unaffected contralateral appendage. No augmentation of other inflammatory cells was observed. Stimulation of isolated cardiac MC with MGF resulted in mediator release. CONCLUSIONS: This study provides evidence that AUTHR is associated with MC increase and redistribution and MGF overexpression. The role of redistributed MC and their mediators in the pathophysiology of atrial thrombosis requires further investigation.

The human cardiac mast cell: localization, isolation, phenotype, and functional characterization.

We have isolated and characterized the human cardiac mast cell (CMC) and compared this novel mast cell (MC type with MC obtained from uterus, skin, and lung. Heart tissue was obtained from 14 patients with cardiomyopathy (CMP, heart transplantation). CMC were isolated by enzymatic digestion using collagenase, pronase-E, hyaluronidase, and DNAse. Substantial amounts of CMC (0.5% to 1.5% of isolated cells) were found in the atrial appendages but not in ventricular digests or other sites of the heart (< 0.1%). In situ staining of atrial tissue revealed the presence of CMC in the myocardium (2.16 +/- 0.7 MC/mm2), endocardium (2.24 +/- 0.9 MC/mm2), and epicardium. As assessed by combined toluidine blue/immunofluorescence staining with monoclonal antibodies (MoAbs), isolated CMC expressed surface IgE, the receptor for stem cell factor (c-kit receptor/CD117), the p24 antigen (CD9), the Pgp-1 homing receptor (CD44), the pan leukocyte antigen (CD45), and the ICAM-1 antigen (CD54). CMC were not recognized by MoAbs to lymphocyte function associated antigen 2 (LFA-2; CD2), T-cell receptor (TcR; CD3), T4 antigen (CD4), LFA-1 alpha-chain (CD11a), C3biR alpha-chain (CD11b), CR4 alpha-chain (CD11c), LPS-R related Ag (CD14), 3-FAL/x-hapten (CD15), Fc gamma RIII (CD16), lactosylceramid (CDw17), the B-cell antigen CD19, or CR1 (CD35). In situ expression of leukocyte antigens on CMC was demonstrable by indirect immunoperoxidase staining technique and double-labeling immunohistochemistry. Almost all CMC (90%) reacted with MoAbs against tryptase and chymase and thus were MCTC. Cardiac mast cells were also stained by the heparin-binding dye Berberine sulfate and expressed measurable amounts of histamine (4.6 +/- 1.4 pg per cell). Cross linking of either IgE receptor or SCF receptor (c-kit) on CMC resulted in histamine secretion (non-specific release: < 6% of total histamine, alpha IgE induced: 12% to 52%; SCF-induced release: 9% to 18%), whereas neither substance P (a skin MC agonist) nor the basophil agonist FMLP showed an effect on CMC. Together, the CMC is an MCTC primarily located in the appendage of the atrium. This novel type of MC exhibits surface membrane antigen and functional properties similar to those of lung and uterus MC.

Endomyocardial HLA expression is increased to the same extent in idiopathic and secondary dilated cardiomyopathy.

In a total of 22 failing hearts from human transplant recipients, the expression of major histocompatibility complex (MHC) molecules, the CD phenotype of infiltrating mononuclear cells, and the number of fibroblasts were analyzed by immunohistochemistry. Compared with 10 non-failing control hearts, significantly higher morphometric area fractions of HLA-ABC and HLA-DR with a concomitant increase of CD3-, CD4- and CD8-positive cells were found to be comparable in 12 patients with idiopathic dilated cardiomyopathy and in 10 patients with secondary heart failure. Furthermore, the similarity of T-cell activation in idiopathic and secondary variants of the disease were substantiated by the following observations: (1) the site-specific distribution of MHC molecules and mononuclear cells in the myocardium was comparable in idiopathic and secondary dilated cardiomyopathy; (2) 6 individuals with lymphocytic aggregates in their myocardium in association with the highest levels of HLA-ABC expression were equally distributed among idiopathic and secondary patient subsets; and (3) expression of HLA-ABC and HLA-DR correlated with that of an endothelial cell marker, von Willebrand factor, in failing myocardia of both study groups. In conclusion, no difference was found in increased MHC molecule expression in failing myocardium of idiopathic and secondary variants of dilated cardiomyopathy, and these entities were not differentially associated with infiltration by increased numbers of T lymphocytes. Hence, we postulate that these immunopathological features are consequences rather than causative factors of myocardial degeneration and dilatation.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum-soluble CD4 as clinical and immunological marker in patients with dilated cardiomyopathy.

Serological markers of cell-mediated immunity, i.e., soluble CD4, soluble interleukin-2 (Il-2) receptor and beta 2-microglobulin, were determined in 60 patients with dilated cardiomyopathy. Compared with normal healthy donors (n = 30) and controls who had coronary artery disease with preserved left ventricular function (n = 20), significantly increased levels associated with the New York Heart Association functional classes have been found in the cardiomyopathy patients, irrespectively of the etiology. Out of the immunological variables tested, serum-soluble CD4 most closely reflected the clinical and hemodynamic stage, predicted the presence of lymphocytic aggregates in the myocardium and correlated with the CD4/CD8 ratios of endomyocardial lymphocytes (r = 0.6, P < 0.05). Conversely, focal mononuclear infiltration of the myocardium was associated with significantly elevated CD4/CD8 ratios (2.1 +/- 0.6 vs. 1.3 +/- 0.2, P < 0.05), higher total numbers and percentages of endomyocardial lymphocytes expressing the pan T-markers CD2 and CD3, more CD45RO/UCHL1-positive cells and more CD4-positive T-helper cells, compared with non-reactive cases the lymphocytes of which were scattered throughout the myocardium. In conclusion, in a subset of cardiomyopathy patients lymphocytic clusters in the myocardium indicated an enhanced cellular immune response predominantly mediated by CD4-positive T-helper lymphocytes with active memory function. This immunopathological condition in the heart can be monitored by serum-soluble CD4.

Specific activation of human mast cells by the ligand for c-kit: comparison between lung, uterus and heart mast cells.

Recent data suggest that stem cell factor (SCF or c-kit ligand, KL) is a major regulator of human mast cells (MCs). In the present study, MCs derived from the lung (n = 8), uterus (n = 14) and heart (n = 4) were analyzed for expression of c-kit receptor and for responses to recombinant SCF. MCs of all organs tested were recognized by mAbs to c-kit (YB5.B8, SR-1) as assessed by combined toluidine blue/immunofluorescence staining. Activation by rhSCF (10 ng/ml, 60 min) resulted in histamine release from lung MCs (SCF 12.8 +/- 2.7% histamine release; control 2.8 +/- 0.8%, p < 0.01), uterus MCs (SCF 16.8 +/- 5.8%; control 5.2 +/- 2.5%, p < 0.01) and heart MCs (SCF 18.4 +/- 2.6%; control 1.7 +/- 0.23%, p < 0.01). Short-term pre-incubation with rhSCF (15 min) did not result in histamine secretion (p > 0.05), but in an increase (lung 2.4 +/- 1.0 fold; uterus 2.1 +/- 1.1 fold, and heart 2.0 +/- 0.4 fold) of alpha IgE-induced mediator release (p < 0.05). The effects of SCF were dose-dependent (maximum responses at 10-100 ng/ml) and dependent on extracellular calcium. A monoclonal antibody to SCF was found to inhibit the effects of SCF on MCs. Furthermore, MCs could be desensitized specifically by pre-incubation of MCs with rhSCF in Ca-free medium. Together, these data suggest that SCF triggers mediator secretion from MCs in various organs via binding to the c-kit receptor.

[Tramadol in postoperative pain therapy. Patient-controlled analgesia versus continuous infusion]. / Tramadol zur postoperativen Schmerztherapie. Patientenkontrollierte Analgesie versus kontinuierliche Infusion.

UNLABELLED: Patient-controlled analgesia (PCA) is a well-proven procedure for individual pain relief in the post-operative period. Despite its superior approach regarding pharmacokinetic and pharmacodynamic considerations, PCA equipment is not available to many in the clinical practice. The goal of this study was to compare the efficacy and safety of PCA with continuous infusion (CI), an easily feasible method, using tramadol (T) as a centrally acting opioid with minor side effects on circulation and ventilation. METHODS: The study was conducted on 20 ASA I or II patients aged 20-60 years undergoing gynecological operations under standardized general anesthesia. They were randomly allocated to two groups receiving i.v. T for postoperative pain relief via Lifecare PCA 4200 Infuser. Group 1 (G1, PCA, n = 10): loading dose 3 mg/kg T, demand dose 30 mg T, lock-out time 5 min, concurrent infusion 5 mg/h T; group 2 (G2, CI, n = 10): loading dose 3 mg/kg T, continuous infusion 0.35 mg/kg per h T. If the analgesia was inadequate, additional doses of 50 mg T were available in G2. During a mean trial period of 20 h, the heart rate, blood pressure, respiratory rate and blood gas analysis were documented. The plasma levels of T and beta-endorphins were determined. The quality of analgesia was assessed by using a verbal and a visual analogue scale. RESULTS: The mean applied doses of T were 339 +/- 100 mg and 364 +/- 46 mg (G1 and G2, respectively) after 6 h and 565 +/- 243 mg and 707 +/- 139 mg (G1 and G2, respectively) in total (NS). Interindividual differences were substantial in G1. Five patients in G2 required an additional dose of 50 mg T. Pain scores decreased rapidly in both groups. The pain relief achieved was comparable and excellent after 6 h. The next morning, G2 reported significantly better analgesia in accordance with the higher availability of T as CI during the sleeping period. Mean plasma T levels were 994 +/- 440 ng/ml and 1170 +/- 357 ng/ml (G1 and G2, respectively). No correlation was found between T-levels and pain scores. The plasma levels of beta-endorphins were substantially elevated after the operation. They returned to normal during T-administration in both groups. No correlation was found between plasma levels of beta-endorphins and pain scores or T-consumption. Hemodynamic changes were minor and without clinical significance. PaO2 and paCO2 remained within small deviations from the physiological range. The respiratory rate, which was initially increased, dropped slightly in both groups. A high incidence of nausea and vomiting was observed, starting in the early phase of the loading dose. CONCLUSIONS: T is well suitable for postoperative pain relief after major gynecological surgery using both PCA and CI. PCA ensures adjustment of the medication to the individual demand, whereas CI provides better analgesia after sleeping periods. We recommend antiemetic prophylaxis before treatment with T.

Autologous and allogenic natural cell mediated cytotoxicity at the single cell level: divergent effects of interferons and interleukin 2 on binding and lysis.

In order to evaluate their divergent effects on binding and lysis of the NCMC, rH IFN-alpha and rH IL-2 were used for the in vitro-preincubation of normal donors' PBL, which were then tested as effector cells against K562 and the long-term cultured melanoma cell line RIMA in the SCCA. Both lymphokines significantly augmented the cytolysis of K562 without relevant influence on the conjugate formation. However, against RIMA IFN-alpha additionally amplified the binding affinity. This in keeping with the other authors' opinion that IFNs have target-specific effects at the single cell level, with the principal activation of already conjugated pre-killer cells against all the target cell lines tested. We performed a therapy-follow-up of the i.p. administration of rH IFN-gamma to patients with ovarian carcinomas in vivo. With the SCCA we detected a significant correlation of the duration of therapy with the autologous cytotoxicity in the ascitic compartment. In one case the increase of this parameter was even exponential. However, the countercurrent trend of the conjugate formation delayed and reduced the activation of the autologous total killer activity. This relative stagnation resulted in the inadequate clinical response of two patients. Moreover, we observed a discrepancy in the development of the autologous and allogeneic SCCA-parameters suggesting strong effects of the peritumorally administered IFN directly on the effusion tumor cells.

IFN-beta 2/IL-6 augments the activity of human natural killer cells.

MHC nonrestricted cytotoxic cells play an important role in the killing of tumor cells in vitro and potentially in vivo. The activity of these cells is regulated by several cytokines such as IL-2 and IFN. In the present study we provide first evidence that IL-6 significantly augments the cytotoxic activity of human NK cells. IL-6 is produced by many different cells and is also known as IFN-beta 2, B cell stimulatory factor 2, hybridoma growth factor, hepatocyte-stimulating factor, and 26 kDa protein. IL-6 stimulates the activity of human CD3- NK cells but not that of CD3+ non-MHC-restricted cytotoxic T lymphocytes. As is the case with IL-2, the IL-6-mediated augmented cytotoxicity was a result of a more efficient lysis, but was not caused by an increased effector to target cell binding. Moreover, the effect of IL-6 on NK cell activity was blocked by a mAb directed against IL-2, and IL-6 itself was found to be a potent inducer of IL-2 production in cultured human PBMC. Thus it may be concluded that IL-6 enhances the cytotoxic activity of NK cells via IL-2. This newly recognized property of IL-6, which is produced by almost any cell, may be of importance in host defense against microbes and malignancies and therefore could contribute to improve the adoptive immunotherapy by using lymphokine-activated killer cells.

[Human natural killer activity in selected test systems and tissue compartments: natural killer cell modulation by biological response modifiers]. / Natural-Killer-(NK-)Aktivität des Menschen in ausgewählten Testsystemen und Gewebekompartments: NK-Modulation durch Biological Response Modifiers (BRM).

In order to evaluate the effect of biological response modifiers on NK- and NK-like activity, interferons were tested in the single cell cytotoxicity assay (SCCA) with various effector/target combinations. alpha Interferon (IFN-alpha) significantly augmented the cytolysis of K 562 in vitro by non-adherent peripheral blood lymphocytes of normal donors without any influence on the binding capacity. Similarly, in vivo, the intraperitoneal administration of gamma Interferon (IFN-gamma) to patients with ovarian carcinomas resulted in a significant increase in the autologous cytotoxicity in the ascitic compartment. Nevertheless the autologous total killer activity was not improved owing to the countercurrent trend of the conjugate formation. Moreover, we detected a discrepancy in the development of the autologous and allogenic parameters as a result of the strong effects of the peritumorally administered IFN on the effusion tumour cells. In order to investigate the role of epidermal NK-like activity in immunosurveillance we tested epidermal cells as effectors against K 562 and the long-term cultured melanoma cell line RIMA. The SCCA detected the ability of conjugate formation without any cytotoxicity, augmentable significantly and in a dose-related manner by IFN-gamma, as the only one of ten tested biological response modifiers.