Macrophage Stimulation with Some Structurally Related Polysaccharides

Abstract

The macrophage-stimulating properties of some structurally related polysaccharides were studied in vitro. When the polysaccharides were presented to the macrophages in a sterically fixed form, i.e. as microparticles, they induced the release of interleukin 1 (IL-1) from the macrophages. Microparticulate 1.3-beta-glucan (curdlan) induced nonspecific macrophage mediated tumour cell killing while 1.4-alpha-glucan (starch), 1.6-alpha-glucan (dextran), and 1.6-alpha-mannan were without effect. The corresponding soluble polysaccharides did not stimulate the macrophages. Kinetic studies showed that although IL-1 was released immediately after stimulation, the macrophages needed a time lag of several days to develop tumour cytotoxicity. The development of cytotoxicity paralleled binding of tumour cells to the macrophages. Resident and inflammatory peritoneal macrophages showed differences in their responses to the polysaccharides. Stationary, resident peritoneal macrophages stimulated by macroparticles secreted high levels of IL-1 but expressed a low cytotoxic activity, while newly recruited inflammatory macrophages released lower levels of IL-1 but readily killed the tumour cells. The influence of cyclo-oxygenase products on the IL-1 release and macrophage cytotoxicity was also investigated. When cyclo-oxygenase was blocked with indomethacin, a significantly higher release of IL-1, and then an increased cytotoxicity, were obtained with 1.3-beta-glucan stimulated macrophages. The results suggest that microparticulate polysaccharides may be useful for studies on the induction of macrophage differentiation and also for studies on nonspecific cellular immune responses in vitro and in vivo.

Prevention and treatment of experimental osteomyelitis in dogs with ciprofloxacin‐loaded crosslinked high amylose starch implants

“…Neovascularization and fibrous septae eventually subdivide CLHAS implants which are then progressively phagocytosed by macrophages [l 11. It is known that macrophages are a key component of the response to implanted CLHAS [lo-121, and that starch has no effect on macrophage nonspecific defense response such as cytotoxic activity [3]. The vacuolated macrophages detected in groups A and D are consistent with phagocytosis of the starch implants.…”

Microporous Polysaccharide Hemospheres and Seroma Formation After Mastectomy and Axillary Dissection in Rats

“…Moreover, MPH may play a positive role in the wound healing process due to its polysaccharide structure, since MPH is a plantbased polysaccharide. Many studies have shown that polysaccharides accelerate the healing process primarily by macrophage activation (13)(14)(15)(16)(17)(18)(19)(20) as well as by fibroblast stimulation (25)(26)(27) and by T-cell stimulation.…”

“…MPH particles form a gelled matrix by concentrating blood solids such as platelets, red blood cells, and blood proteins such as, albumin, thrombin and fibrinogen; thus, are used to achieve hemostasis in case of persistent bleeding (11,12). Also, many studies have shown that polysaccharides accelerate and enhance wound healing via various mechanisms, primarily by increasing the activity of macrophages (13)(14)(15)(16)(17)(18)(19)(20). It can be presumed that the MPH can reduce seroma formation by virtue of these characteristics, by preventing the mechanisms causing seroma formation.…”

Administration of β‐glucan following Leishmania major infection suppresses disease progression in mice

“…This is in line with the documented specificity of p-glucan as an activator of macrophages (Seljelid, Bogwald & Lundwall 198 1, Artursson, Edman & Ericsson 1987). While starch particles are avidly phagocytosed by macrophages and starch gels induce peritoneal inflammation, they do not activate macrophages for tumour cell killing (Artursson et al 1987) or leishmanicidal activity (Hoover & Nacy 1984).…”