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OK-432, penicillin-killed Streptococcus pyogenes, is used in treating lymphangiomas and carcinomas. We have studied proinflammatory interleukin (IL) secretion following OK-432 stimulation of total blood, peripheral blood mononuclear cell (PBMC) and purified monocytes in vitro. OK-432 stimulation of purified monocytes gave IL-1beta, IL-1RA, IL-6, IL-12p40 and tumour necrosis factor (TNF)-alpha response. OK-432 stimulation of cells within blood did, however, not yield TNF-alpha secretion. When PBMC or monocytes were cultured in low-attachment wells a decreased IL secretion was observed compared to adherent cells. Inhibition of Syk kinase with piceatannol, only at high, non-specific doses, but not PI3 kinase inhibition with LY294002 or Wortmannin, decreased monocyte IL response to OK-432. This shows that beta(1-3)-integrin receptor function is not necessary for monocyte OK-432-stimulated TNF-alpha secretion. Direct blockage of the beta(2)-integrin (CD18) receptor by anti-CD18 antibody was also unable to prevent the stimulating effects of OK-432 in human monocytes. On the other hand, Syk phosphorylation is elevated upon adherence of monocytes and this is further increased by OK-432 stimulation, as shown by Western blot. The Fc-receptor was also ruled out as a main receptor of the OK-432 monocyte response. In conclusion, TNF-alpha secretion is only found in monocytes removed from blood. This TNF-alpha secretion is not mediated through the beta(1-3)-integrin receptors. OK-432 may act as a target-seeking substance whereby only monocytes adhered, e.g. to a tumour cell, become cytotoxic in part explaining why OK-432 is well suited as a cancer treatment drug.

Conclusion. Tumour-associated macrophages (TAMs) in head and neck squamous cell carcinomas (HNSCCs) secrete interleukin 6 (IL-6) and monocyte chemotactic protein (MCP-1) that can be down-regulated by L-leucine-methylester (LLME); however, there is no qualitative difference between function of TAMs and tissue macrophages in mucosa as measured by IL-6 and MCP-1 secretion. Objectives. TAMs play an important role in the interaction with tumour cells in malignant tumours. The cells in the tumours that are the main sources of the various signal substances need to be further elucidated. The aim of this investigation was to reveal whether TAMs in HNSCCs secrete IL-6 and MCP-1. These cytokines influence tumour cell growth and macrophage influx in tumours, respectively. Materials and methods. In order to inhibit macrophage function in F-spheroids, in some experiments the tissue fragments were initially incubated with LLME, a substance that selectively inhibits function of phagocytes. IL-6 and MCP-1 secretion from untreated F-spheroids was compared to cytokine secretion from LLME-treated F-spheroids as measured by ELISA. Results. LLME did not affect the viability of F-spheroids and reduced IL-6 and MCP-1 secretion from monocyte-derived macrophages in vitro. F-spheroids from LLME-treated tissue fragments showed lower IL-6 and MCP-1 secretion compared with F-spheroids from tissue fragment untreated with LLME.

This study was performed in order to determine how monocytes and macrophages in co-culture with autologous head and neck squamous cell carcinoma (HNSCC) tumor tissue regulate the secretion of monocyte chemotactic protein-1 (MCP-1). The levels of MCP-1 were measured when autologous monocytes or monocyte-derived macrophages (MDMs) were co-cultured in vitro with autologous fragment (F)-spheroids established from HNSCC tumors or benign mucosa serving as control. MCP-1 secretion from co-culture stimulated monocytes and MDMs was increased compared to spontaneous MCP-1 secretion. With prolonged co-culture, MDMs showed a steady-state MCP-1 secretion above background levels for up to 96 h, even with change of co-culture media every 24 h. Addition of an anti-MCP-1 antibody to the medium decreased co-culture-induced monocyte IL-6 secretion. Addition of lipopolysaccharide (LPS) (1 [microg/ml) reduced MCP-1 secretion compared to spontaneous secretion in monocyte cultures. F-spheroids also secrete MCP-1, but at insignificant levels compared to the MCP-1 secretion from monocytes and MDMs. MCP-1 secretion from monocytes/MDMs is regulated differently when co-culture stimulation is compared to LPS-stimulation. Monocytes and MDMs expressed MCP-1 mRNA at a high level in all tested conditions: stimulated in co-culture, not stimulated or stimulated with LPS, indicating post-transcriptional regulation of MCP-1 secretion. The secretion of MCP-1 from tumor-derived F-spheroids, and the maintenance of co-culture MCP-1 secretion from MDMs in vitro, suggests that tumor-associated macrophages are a source of MCP-1 in HNSCC tumors.

The secretion of interleukin (IL)-1 beta, IL-6 and tumour necrosis factor (TNF)-alpha were compared when freshly isolated autologous monocytes or monocytederived macrophages (MDMs) were co-cultured in vitro with autologous fragment (F)-spheroids established from a series of head and neck squamous cell carcinoma (HNSCC) patients. F-spheroids were generated from the malignant tumour (M-spheroids) or from benign mucosa (B-spheroids) from which the tumour originated control. If monocytes maturated towards MDMs before co-culture, the IL-6 secretion declined dependent on the extent of the MDM maturation by both M- and B-spheroid stimulation. When MDMs maturated in continuous co-culture, a steady-state secretion of IL-6 continued for several days but diminished when the culture medium was changed every 24 h. No co-culture-induced IL-1 beta or TNF-alpha was determined. Both the cytokine secretion and the mRNA gene expression revealed a different monocyte/MDM activation when co-culture and lipopolysaccharide (LPS)-stimulation were compared. Addition of anti-CD14 (10 microg/ml) decreased monocyte LPS-stimulated, but increased monocyte co-culture stimulated IL-6 secretion. In conclusion, M- and B-spheroids similarly stimulated monocytes and to a lesser extent MDMs. MDMs that maturated with F-spheroids present, retained responsiveness at the monocyte level. Co-culture-induced monocyte stimulation, as measured by IL-6 secretion, was not dependent on activation via the CD14 molecule.

Macrophages were harvested from home cage control (HCC) mice, and from mice which had been stressed by repeated brief exposures (3-8 min) to cold water at 10-15 degrees C twice daily for 8 or 14 days. Macrophages obtained from mice stressed 8 or 14 days compared to macrophages from HCC mice showed in vitro increased amounts of membrane-bound prothrombinase activity, whereas the thrombin degradation activity was unchanged. Furthermore, macrophages of mice stressed 8 days showed increased release of coagulation factor X/Xa to supernatant in vitro. These findings suggest an increased amount of prothrombinase complex enzymes on the surface of macrophages from mice stressed 8 days, and increased activity of the prothrombinase enzyme in macrophages from mice stressed 14 days. The synthesis of proteoglycans (PG) and glycosaminoglycans (GAG) was increased in macrophages from mice stressed 8 days compared to macrophages from HCC mice and mice stressed 14 days. When macrophages from mice stressed 8 days or HCC mice were stimulated in vitro with phorbol myristate acetate (PMA) and IL-1 or PMA and IL-2, a changed PG/GAG synthesis was observed only in macrophages from the HCC animals. Furthermore, both the tumour cytotoxicity and the released tumour necrosis factor (TNF) were decreased from macrophages from mice stressed 14 days compared to HCC mice. The results suggest that the macrophages of stressed mice have an altered mode of function more complex than a simple general suppression or activation.

Mice stressed daily by brief cold water immersions for 1, 8 or 14 days showed changes in immune system function which were dependent on the number of mice per cage, frequency of stress exposures and total number of stress exposures. Changed percentages of spleen B and CD4, but not of CD8 cells were determined when the mice were stressed either once or twice daily. With CD4 cells, increased percentages were seen after stress once daily but a decreased percentage was seen after stress twice daily. Furthermore, the Concanavalin A-stimulated spleen cell mitogenesis was decreased after 1 day of stress in mice stressed once daily as opposed to after 8 and 14 days of stress in mice stressed twice daily. After 14 days of stress, the lipopolysaccharide stimulated mitogenesis was increased if the mice were stressed once daily but decreased if the mice were stressed twice daily. With two mice per cage, we observed a decreased spleen cell mitogenesis after 14 days of stress. With four mice per cage, the spleen cell mitogenesis was decreased after 8 and 14 days of stress. If spleen cell populations from mice stressed twice daily for 8 days were depleted of macrophages and CD4 or CD8 cells, the effect of stress on the mitogenesis was removed from the CD8 cells. Spleen cells of mice stressed for 14 days showed a decreased mitogenesis when depleted of adherent cells and reconstituted with adherent cells from control mice. Furthermore, the adherent cells from these mice had decreased ability to support mitogenesis of adherent cell-depleted spleen cells from control mice as well as a decreased IL-1 production.