Detection of Fcγ receptors on human endothelial cells stimulated with cytokines tumour necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ)

This investigation was conducted to detect Fcγ receptors (FcγR) on cytokine-stimulated human endothelial cells (EC) by measuring anti-FcγR MoAb binding with an ELISA. TNF-α and IFN-γ significantly increased the expression of FcγR type II (FcγRII) and type III (FcγRIII) on aortic EC. Simultaneous treatment with both cytokines had a synergistic effect and pretreatment of EC with IFN-γ augmented the effect of TNF-α. The greatest effect was the increase (up to four-to-six-fold) in expression of FcγRII found by the simultaneous treatment of aortic EC with both cytokines. The receptors were expressed on the cell surface and showed receptor capping after incubation at 37°C. This study showed that the inflammatory cytokines TNF-α and IFN-γ enhanced low-affinity FcγR expression on human EC in vitro. The expression of FcγR may contribute to the specific localization of circulating immune complexes on blood vessels in areas of vasculitis.     

Characterization of peroxidase:anti-peroxidase immune complexes by capillary zone electrophoresis and high-performance size-exclusion chromatography

Determination of the molecular constituents of commercial peroxidase:anti-peroxidase (PAP) preparations is necessary for the proper interpretation of PAP applications based on competitive binding assay. Capillary zone electrophoresis with field 300 V/cm, 40 cm capillary length (20 cm effective length), and high-performance size exclusion chromatography equipped with Superose 12 HR10/30 column revealed that a PAP preparation used for Fc gamma receptor studies contained multiple sizes of immune complexes, an excess amount of free peroxidase, and little or no free anti-peroxidase antibody. The antibody:antigen ratios of the three major immune complex components were 2:2, 1:2, and 1:1. These techniques provide useful methods of qualitative, as well as quantitative analysis of PAP preparations.     

In vivo and in vitro characteristics of interleukin 6-transfected B16 melanoma cells.

Interleukin 6 (IL-6) is a multifunctional cytokine important in the inflammatory response. Its potential role as an antitumor agent has been suggested by its demonstrated activity in a variety of tumor models. The mechanism of antitumor activity has been proposed to be its enhancement of cytotoxic T-cell function. In the current work we demonstrate clear antitumor activity for this cytokine in a nonimmunogenic tumor system. B16 melanoma cells transfected with the human IL-6 complementary DNA demonstrated slower tumor growth in vivo. Tumors that developed from these cells had a prominent stromal matrix, an easily recognized infiltration of inflammatory cells, fewer mitotic figures, and fewer blood vessels. These in vivo findings corresponded with a greater adhesion of the IL-6-transfected B16 cells to stromal matrix proteins (laminin, fibronectin, and vitronectin) and a less prominent vascular response in an intradermal angiogenesis assay. Therefore, we propose that with weakly antigenic tumors, such as B16 melanoma, IL-6 may mediate important antitumor responses by nonspecific proinflammatory mechanisms.     

A phase I trial of 14-day continuous intravenous infusion mitoxantrone.

Based on clinical evidence that prolonged exposure to anti-neoplastic agents may ameliorate dose-limiting toxicity while facilitating anti-tumor activity, we conducted a phase I trial of 14-day continuous intravenous infusion mitoxantrone. Study objectives were to: (1) determine the maximally tolerated dose for phase II trials; (2) determine the incidence and severity of side effects; and (3) study the pharmacokinetics of continuous infusion mitoxantrone. Sixteen patients with drug-resistant advanced cancers were entered into the trial. Three or more patients were treated at each dose level (1.0, 1.25, and 1.5 mg/m2/day) for a total of 33 courses (mean 2.1 courses/patient, range, 1-4). Courses were repeated every 4 weeks. The maximally tolerated dose (MTD) was found to be 1.5 mg/m2/day. At this dose four of six patients had grade III or IV leukopenia (mean WBC nadir 1900/microliters, range, 800-3600/microliters). Other toxicities were grade I or II stomatitis (two patients), grade I diarrhea (one patient), and grade I nausea (one patient). Renal and hepatic toxicity were not observed. No alopecia or infectious complications occurred. Pharmacokinetic studies were performed using high-performance liquid chromatography (HPLC). Steady-state plasma levels at the 1.5 mg/m2/day dose were reached by 48 h, with a mean steady-state plasma concentration of 3.2 +/- 0.7 ng/ml, mean total body clearance of 340 +/- 79 ml/min/m2, and mean area under the plasma disappearance curve (AUC) of 955 +/- 185 micrograms h/l. No responses were observed, although no patients with mitoxantrone-sensitive tumors were treated.(ABSTRACT TRUNCATED AT 250 WORDS)     

Investigation of tumor angiogenesis in an id mouse model: role of host-tumor interactions

The role of host-tumor interactions in tumor angiogenesis was studied in an id mouse model. Although many previous studies have described the effects of certain host factors (age, nutritional status, tumor location, etc.) on experimental tumor systems, the effects of these factors on tumor angiogenesis have not been reported. In preliminary studies we inoculated cloned tumor cells id into syngeneic mice and found positional differences in tumor growth that did not correlate with measured angiogenesis levels. In addition, while tumor growth was inhibited by radiation, tumor-induced (but not fibroblast-induced) angiogenesis was not. This id system may provide an assay not only for examining the effect of host factors on tumor angiogenesis, but also for elucidation of the mechanisms underlying neovascular induction and host response.     

Effect of host age on tumor-associated angiogenesis in mice.

Previous reports on the slower growth of tumors in senescent mice have suggested a decrease in tumor angiogenesis in these animals, but such an observation has not yet been documented quantitatively. In this study, we report the relative amount of tumor angiogenesis and tumor volume for two different types of tumor in 11 young (8-9-wk old) versus nine older (19-mo old) male C57BL/10 mice. B16 melanoma or SP1 methylcholanthrene-induced fibrosarcoma cells were injected into the ventral skin of mice. After 3 days, the mice were killed and the injection sites were examined for angiogenesis surrounding the tumor (centrally directed tumor angiogenesis), nerve-associated angiogenesis, and tumor volume. In the older mice, there was significantly less centrally directed tumor angiogenesis for both tumors tested, and nerve-associated angiogenesis was decreased for B16 melanoma. The mean tumor volume for the B16 implants was smaller for the older animals, but the mean SP1 tumor volumes were identical for both age groups. These findings support the hypothesis that tumor growth in older animals is associated with less formation of new blood vessels, and this may explain the slower tumor growth observed in aged animals with certain experimental tumors.     

Expression of endothelial cell IgG Fc receptors and markers on various cultures

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