Activation of macrophages by ether analogues of lysophospholipids

M2 tumor-associated macrophages and CXCL2 induce lipid remodeling in hepatocellular carcinoma cell lines

Primary hepatocellular carcinoma (HCC) is one of the most common malignant tumors, but its pathogenesis remains incompletely elucidated. Recently, many studies indicated that lipid remodeling plays an important role in the occurrence and development of HCC. Furthermore, lipids have been proven to be indispensable mediators in promoting communication between tumor cells and extracellular matrix in the tumor microenvironment. Thus, this study aims to comprehensively investigate the process of lipid remodeling during HCC metastasis based on the LC-electrospray ionization-MS (LC-ESI-MS) combined with multiple reaction monitoring technology. M2 tumor-associated macrophages and the recombinant human protein CXCL2 were used to simulate the tumor microenvironment. After co-incubating SMMC7721 and MHCC97-H cell lines with M2 tumor-associated macrophages or the recombinant human protein CXCL2 for 48 h, LC-ESI-MS was used to quantify the levels of two major classes of lipid molecules, namely, glycerophospholipids and sphingolipids. Our results suggest that lipid remodeling in the tumor microenvironment may promote the migration and invasion of HCC cell lines.

Immunotherapy with GcMAF revisited - A critical overview of the research of Nobuto Yamamoto

This overview describes the research of Nobutu Yamamoto (Philadelphia) concerning immunotherapy with GcMAF for patients with cancer and for patients infected with pathogenic envelope viruses. GcMAF (Group-specific component Macrophage-Activating Factor) is a mammalian protein with an incredible potency to directly activate macrophages. Since the late 1980s Yamamoto's investigations were published in numerous journals but in order to understand the details of his research, a minute survey of many of his patents was required. But even then, regrettably, a precise description of his experiments was sometimes lacking. This overview tries to summarize all of Yamamoto's research on GcMAF, as well as some selected more recent papers from other investigators, who tried to verify and/or reproduce Yamamoto's reports. In my opinion the most important result of the GcMAF research deserves widespread renewed attention: human GcMAF injections (100 ng per week, intramuscular or intravenous) can help to cure patients with a great variety of cancers as well as patients infected with pathogenic envelope viruses like the human immunodeficiency virus 1 (HIV-1), influenza, measles and rubella (and maybe also SARS-CoV-2). From Yamamoto's data it can be calculated that GcMAF is a near-stoichiometric activator of macrophages. Yamamoto monitored the progress of his immunotherapy via the serum level of an enzyme called nagalase (α-N-acetylgalactosaminidase activity at pH 6). I have extensively discussed the properties and potential catalytic site of this enzyme activity in an Appendix entitled: "Search for the potential active site of the latent α-N-acetylgalactosaminidase activity in the glycoproteins of some envelope viruses".

Specific and non-specific immunity of piglets from sows fed diets containing specific fatty acids in field conditions

The transfer of passive immunity from sows to piglets is important and it is the first immune protection of the new born piglet. Improving sows immunity by adding immuno-stimulating product in sows diet can positively affect colostrum composition and transfer of immune molecules to piglets. The aim of the current study is to evaluate the benefit of a different solution, made of specific fatty acids from marine origin that have been used in human medicine for decades, for sows and piglets. Two trials were conducted in commercial farm, involving 240 sows at different periods of the year. Sows were divided in a control group, without supplementation, and a test group, supplemented with the feed additive from the 90th day of gestation to weaning. Sows body condition, piglets viability and growth were recorded. Milk immunoglobulin content was measured, as well as Aujeszky antibodies in sows and piglets blood as marker of specific immunity, and blood bactericidal activity, complement activity and lysozyme as markers of non specific immunity. No effect of the product was observed on piglets zootechnical criteria and specific immunity parameters but significant improvement of piglet non specific immunity, was observed. No difference was observed neither in the piglets blood PRRSV and PCV2 antibodies and viruses nor in Aujeszky antibodies. Blood complement activity seems to be an accurate indicator of immuno-stimulating additive efficiency. Giving alkyl-glycerol fatty acids to sows in late gestation and lactation can improve the passive immunity transfer to piglets.

Immunotherapy for Prostate Cancer with Gc Protein-Derived Macrophage-Activating Factor, GcMAF

Serum Gc protein (known as vitamin D(3)-binding protein) is the precursor for the principal macrophage-activating factor (MAF). The MAF precursor activity of serum Gc protein of prostate cancer patients was lost or reduced because Gc protein was deglycosylated by serum alpha-N-acetylgalactosaminidase (Nagalase) secreted from cancerous cells. Therefore, macrophages of prostate cancer patients having deglycosylated Gc protein cannot be activated, leading to immunosuppression. Stepwise treatment of purified Gc protein with immobilized beta-galactosidase and sialidase generated the most potent MAF (termed GcMAF) ever discovered, which produces no adverse effect in humans. Macrophages activated by GcMAF develop a considerable variation of receptors that recognize the abnormality in malignant cell surface and are highly tumoricidal. Sixteen nonanemic prostate cancer patients received weekly administration of 100 ng of GcMAF. As the MAF precursor activity increased, their serum Nagalase activity decreased. Because serum Nagalase activity is proportional to tumor burden, the entire time course analysis for GcMAF therapy was monitored by measuring the serum Nagalase activity. After 14 to 25 weekly administrations of GcMAF (100 ng/week), all 16 patients had very low serum Nagalase levels equivalent to those of healthy control values, indicating that these patients are tumor-free. No recurrence occurred for 7 years.

Inhibitory effect of vitamin D-binding protein-derived macrophage activating factor on DMBA-induced hamster cheek pouch carcinogenesis and its derived carcinoma cell line

This study investigated the inhibitory effect of vitamin D-binding protein-derived macrophage-activating factor (GcMAF) on carcinogenesis and tumor growth, using a 9,10-dimethyl-1,2-benzanthracene (DMBA)-induced hamster cheek pouch carcinogenesis model, as well as the cytocidal effect of activated macrophages against HCPC-1, a cell line established from DMBA-induced cheek pouch carcinoma. DMBA application induced squamous cell carcinoma in all 15 hamsters of the control group at approximately 10 weeks, and all 15 hamsters died of tumor burden within 20 weeks. By contrast, 2 out of the 14 hamsters with GcMAF administration did not develop tumors and the remaining 12 hamsters showed a significant delay of tumor development for approximately 3.5 weeks. The growth of tumors formed was significantly suppressed and none of the hamsters died within the 20 weeks during which they were observed. When GcMAF administration was stopped at the 13th week of the experiment in 4 out of the 14 hamsters in the GcMAF-treated group, tumor growth was promoted, but none of the mice died within the 20-week period. On the other hand, when GcMAF administration was commenced after the 13th week in 5 out of the 15 hamsters in the control group, tumor growth was slightly suppressed and all 15 hamsters died of tumor burden. However, the mean survival time was significantly extended. GcMAF treatment activated peritoneal macrophages in vitro and in vivo, and these activated macrophages exhibited a marked cytocidal effect on HCPC-1 cells. Furthermore, the cytocidal effect of activated macrophages was enhanced by the addition of tumor-bearing hamster serum. These findings indicated that GcMAF possesses an inhibitory effect on tumor development and growth in a DMBA-induced hamster cheek pouch carcinogenesis model.

Multiple beneficial health effects of natural alkylglycerols from shark liver oil

Alkylglycerols (alkyl-Gro) are ether lipids abundant in the liver of some elasmobranch fish species such as ratfishes and some sharks. Shark liver oil from Centrophorus squamosus (SLO), or alkyl-Gro mix from this source, have several in vivo biological activities including stimulation of hematopoiesis and immunological defences, sperm quality improvement, or anti-tumor and anti-metastasis activities. Several mechanisms are suggested for these multiple activities, resulting from incorporation of alkyl-Gro into membrane phospholipids, and lipid signaling interactions. Natural alkyl-Gro mix from SLO contains several alkyl-Gro, varying by chain length and unsaturation. Six prominent constituents of natural alkyl-Gro mix, namely 12:0, 14:0, 16:0, 18:0, 16:1 n-7, and 18:1 n-9 alkyl-Gro, were synthesized and tested for anti-tumor and anti-metastatic activities on a model of grafted tumor in mice (3LL cells). 16:1 and 18:1 alkyl-Gro showed strong activity in reducing lung metastasis number, while saturated alkyl- Gro had weaker (16:0) or no (12:0, 14:0, 18:0) effect. Multiple compounds and mechanisms are probably involved in the multiple activities of natural alkyl-Gro.

Immunotherapy of metastatic colorectal cancer with vitamin D-binding protein-derived macrophage-activating factor, GcMAF

Serum vitamin D binding protein (Gc protein) is the precursor for the principal macrophage-activating factor (MAF). The MAF precursor activity of serum Gc protein of colorectal cancer patients was lost or reduced because Gc protein is deglycosylated by serum alpha-N-acetylgalactosaminidase (Nagalase) secreted from cancerous cells. Deglycosylated Gc protein cannot be converted to MAF, leading to immunosuppression. Stepwise treatment of purified Gc protein with immobilized beta-galactosidase and sialidase generated the most potent macrophage-activating factor (GcMAF) ever discovered, but it produces no side effect in humans. Macrophages treated with GcMAF (100 microg/ml) develop an enormous variation of receptors and are highly tumoricidal to a variety of cancers indiscriminately. Administration of 100 nanogram (ng)/ human maximally activates systemic macrophages that can kill cancerous cells. Since the half-life of the activated macrophages is approximately 6 days, 100 ng GcMAF was administered weekly to eight nonanemic colorectal cancer patients who had previously received tumor-resection but still carried significant amounts of metastatic tumor cells. As GcMAF therapy progressed, the MAF precursor activities of all patients increased and conversely their serum Nagalase activities decreased. Since serum Nagalase is proportional to tumor burden, serum Nagalase activity was used as a prognostic index for time course analysis of GcMAF therapy. After 32-50 weekly administrations of 100 ng GcMAF, all colorectal cancer patients exhibited healthy control levels of the serum Nagalase activity, indicating eradication of metastatic tumor cells. During 7 years after the completion of GcMAF therapy, their serum Nagalase activity did not increase, indicating no recurrence of cancer, which was also supported by the annual CT scans of these patients.

Immunotherapy of metastatic breast cancer patients with vitamin D-binding protein-derived macrophage activating factor (GcMAF)

Serum vitamin D3-binding protein (Gc protein) is the precursor for the principal macrophage activating factor (MAF). The MAF precursor activity of serum Gc protein of breast cancer patients was lost or reduced because Gc protein was deglycosylated by serum alpha-N-acetylgalactosaminidase (Nagalase) secreted from cancerous cells. Patient serum Nagalase activity is proportional to tumor burden. The deglycosylated Gc protein cannot be converted to MAF, resulting in no macrophage activation and immunosuppression. Stepwise incubation of purified Gc protein with immobilized beta-galactosidase and sialidase generated probably the most potent macrophage activating factor (termed GcMAF) ever discovered, which produces no adverse effect in humans. Macrophages treated in vitro with GcMAF (100 pg/ml) are highly tumoricidal to mammary adenocarcinomas. Efficacy of GcMAF for treatment of metastatic breast cancer was investigated with 16 nonanemic patients who received weekly administration of GcMAF (100 ng). As GcMAF therapy progresses, the MAF precursor activity of patient Gc protein increased with a concomitant decrease in serum Nagalase. Because of proportionality of serum Nagalase activity to tumor burden, the time course progress of GcMAF therapy was assessed by serum Nagalase activity as a prognostic index. These patients had the initial Nagalase activities ranging from 2.32 to 6.28 nmole/min/mg protein. After about 16-22 administrations (approximately 3.5-5 months) of GcMAF, these patients had insignificantly low serum enzyme levels equivalent to healthy control enzyme levels, ranging from 0.38 to 0.63 nmole/min/mg protein, indicating eradication of the tumors. This therapeutic procedure resulted in no recurrence for more than 4 years.

A new procedure for experimental autoimmune uveitis with small uveitogenic peptides

PURPOSE

Demonstration of experimental autoimmune uveitis (EAU) with extremely small, fragmented peptides (12-30 amino acid residues) of interphotoreceptor retinoid-binding protein (IRPB).

METHOD

Very small fragmented peptides (no. 854, 888, 907, and 1057) were conjugated to heat-killed Group A Streptococcus cells and administered as a single intravenous injection to Lewis rats. A non-uveitogenic peptide 950 was also conjugated to heat-killed Streptococcus and administered. Administration of a mixture of small peptides and Streptococcus was a control for the peptides conjugated with Streptococcus.

RESULTS

The uveitogenic peptide/Streptococcus conjugates produced uveitis inflammatory responses in the uvea, retina and pineal gland. Administration of mixtures of small peptides and Streptococcus cells, and a non-uveitogenic peptide 950 conjugated with Streptococcus did not produce autoimmune uveitis.

CONCLUSIONS

Since mixtures of small uveitogenic peptides and Streptococcal cells did not develop autoimmune uveitis, conjugated Streptococcal cells provided a vehicle for macrophage phagocytosos of very small uveitogenic IRBP peptides. Subsequent antigen presentation from macrophages to lymphocytes developed autoimmune uveitis. Peptide 888, one of four IRBP peptides that encompass the major uveitogenic domain, proved to be the most effective in development of uveitis.

Mechanisms of action of lysophospholipid analogues against trypanosomatid parasites

Lysophospholipid analogues (LPAs) comprise a class of metabolically stable compounds that have been developed as anticancer agents for over two decades, but which have also potent and selective antiparasitic activity, particularly against trypanosomatid parasites such as Leishmania and Trypanosoma cruzi, both in vitro and in vivo. The in vivo activities of LPAs result from direct effects on their target cells and are not dependent on a functional immune system. Because of their chemical nature, LPAs have a potential for interaction with a variety of subcellular structures and biochemical pathways. However, in mammalian cells LPA-induced growth inhibition and programmed cell death is usually associated with a blockade of phosphatidylcholine (PC) biosynthesis at the level of CTP: phosphocholine citidyltransferase, probably through an increase of cellular ceramide levels due to depressed sphingomyelin synthesis. Although in trypanosomatid parasites much less information is available, inhibition of PC biosynthesis by LPA has also been documented but at the level of phosphatidylethanolamine N-methyl-transferase, as well as LPA-induced classical apoptotic phenomena. The higher activity of LPAs as inhibitors of PC biosynthesis in parasites than in mammalian cells, probably due to different biochemical pathways involved in the two types of cells, could explain their selective antiparasitic action in vivo.

Structurally well-defined macrophage activating factor derived from vitamin D3-binding protein has a potent adjuvant activity for immunization

Freund's adjuvant produced severe inflammation that augments development of antibodies. Thus, mixed administration of antigens with adjuvant was not required as long as inflammation was induced in the hosts. Since macrophage activation for phagocytosis and antigen processing is the first step of antibody development, inflammation-primed macrophage activation plays a major role in immune development. Therefore, macrophage activating factor should act as an adjuvant for immunization. The inflammation-primed macrophage activation process is the major macrophage activating cascade that requires participation of serum vitamin D3-binding protein (DBP; human DBP is known as Gc protein) and glycosidases of B and T lymphocytes. Stepwise incubation of Gc protein with immobilized beta-galactosidase and sialidase efficiently generated the most potent macrophage activating factor (designated GcMAF) we have ever encountered. Administration of GcMAF (20 or 100 pg/mouse) resulted in stimulation of the progenitor cells for extensive mitogenesis and activation of macrophages. Administration of GcMAF (100 pg/mouse) along with immunization of mice with sheep red blood cells (SRBC) produced a large number of anti-SRBC antibody secreting splenic cells in 2-4 days. Thus, GcMAF has a potent adjuvant activity for immunization. Although malignant tumours are poorly immunogenic, 4 days after GcMAF-primed immunization of mice with heat-killed Ehrlich ascites tumour cells, the ascites tumour was no longer transplantable in these mice.

Some biological actions of alkylglycerols from shark liver oil

Shark liver oil has been used for over 40 years as both a therapeutic and preventive agent. The active ingredients in shark liver oil have been found to be a group of ether-linked glycerols known as alkylglycerols. Initial clinical use was for treating leukemias, and later to prevent radiation sickness from cancer x-ray therapy. Studies over the last 30 years have shown that alkylglycerols are multifunctional. The level of natural alkylglycerols rises within tumor cells, apparently in an effort to control cell growth. Recent studies indicate that the activation of protein kinase C, an essential step in cell proliferation, can be inhibited by alkylglycerols. This action suggests a competitive inhibition of 1.2-diacylglycerol by alkylglycerols. Further studies on the immunostimulatory action of alkylglycerols suggest a primary action on the macrophage. The process of macrophage activation has been demonstrated with both synthetic and natural alkylglycerols. While the exact mechanism has not been found, both an autocrine and paracrine system have been suggested. Shark liver is a major natural source of alkylglycerols, which have no known side effects in dosages of 100 mg three times a day. The information presented in this article suggests that alkylglycerols may be used both as an adjunct therapy in the treatment of neoplastic disorders and as an immune booster in infectious diseases.

Structural definition of a potent macrophage activating factor derived from vitamin D3-binding protein with adjuvant activity for antibody production

Incubation of human vitamin D3-binding protein (Gc protein), with a mixture of immobilized beta-galactosidase and sialidase, efficiently generated a potent macrophage activating factor, a protein with N-acetylgalactosamine as the remaining sugar. Stepwise incubation of Gc protein with immobilized beta-galactosidase and sialidase, and isolation of the intermediates with immobilized lectins, revealed that either sequence of hydrolysis of Gc glycoprotein by these glycosidases yields the macrophage-activating factor, implying that Gc protein carries a trisaccharide composed of N-acetylgalactosamine and dibranched galactose and sialic acid termini. A 3 hr incubation of mouse peritoneal macrophages with picomolar amounts of the enzymatically generated macrophage-activating factor (GcMAF) resulted in a greatly enhanced phagocytic activity. Administration of a minute amount (10-50 pg/mouse) of GcMAF resulted in a seven- to nine-fold enhanced phagocytic activity of macrophages. Injection of sheep red blood cells (SRBC) along with GcMAF into mice produced a large number of anti-SRBC antibody secreting splenic cells in 2-4 days.

Structural modification of serum vitamin D3-binding protein and immunosuppression in AIDS patients

A serum glycoprotein, vitamin D3-binding protein (Gc protein), can be converted by beta-galactosidase of stimulated B lymphocytes and sialidase of T lymphocytes to a potent macrophage-activating factor (MAF), a protein with N-acetylgalactosamine as the remaining sugar moiety. Thus, Gc protein is a precursor for MAF. Treatment of purified Gc protein with immobilized beta-galactosidase and sialidase generates an extremely high-titered MAF (GcMAF). When peripheral blood monocytes/macrophages of 46 HIV-infected patients were treated with GcMAF (100 pg/ml), the monocytes/macrophages of all patients were efficiently activated. However, the MAF precursor activity of plasma Gc protein was low in 16 (35%) of of these patients. Loss of the MAF precursor activity appeared to be due to deglycosylation of plasma Gc protein by alpha-N-acetylgalactosaminidase found in the patient blood stream. Levels of plasma alpha-N-acetylgalactosaminidase activity in individual patients had an inverse correlation with the MAF precursor activity of their plasma Gc protein. Thus, precursor activity of Gc protein and alpha-N-acetylgalactosaminidase activity in patient blood can serve as diagnostic and prognostic indices.

Analogs of alkyllysophospholipids: chemistry, effects on the molecular level and their consequences for normal and malignant cells

In the search for new approaches to cancer therapy, the first alkyllysophospholipid (ALP) analogs were designed and studied about two decades ago, either as potential immunomodulators or as antimetabolites of phospholipid metabolism. In the meantime, it has been demonstrated that they really act in this way. However, their special importance is based on the fact that, in addition, they interfere with key events of signal transduction, such as hormone (or cytokine)-receptor binding or processing, protein kinase C or phospholipase C function and phosphatidylinositol and calcium metabolism. There are no strict structural requirements for their activity. Differences in the cellular uptake or the state of cellular differentiation seem to be mainly responsible for higher or lower sensitivities of cells towards ALP analogs. Consequences of the molecular effects mentioned on the cellular level are cytostasis, induction of differentiation (while in contrast the effects of known inducers of differentiation such as 12-O-tetradecanoylphorbol-13-acetate are inhibited, probably as a consequence of protein kinase C inhibition) and loss of invasive properties. Already in sublytic concentrations, alterations in the membrane structure were observed, and lysis may begin at concentrations not much higher than those causing the other effects described. Few ALP analogs have already entered clinical studies or are in clinical use. ALP analogs are the only antineoplastic agents that do not act directly on the formation and function of the cellular replication machinery. Therefore, their effects are independent of the proliferative state of the target cells. Because of their interference with cellular regulatory events, including those failing in cancer cells, ALP analogs, beyond their clinical importance, are interesting model compounds for the development of new, more selective drugs for cancer therapy.

Roles of beta-galactosidase of B lymphocytes and sialidase of T lymphocytes in inflammation-primed activation of macrophages

The outer surface of mouse B lymphocytes carries constitutive and inducible beta-galactosidase isozymes. A brief (30 min) treatment of B lymphocytes with lysophosphatidylcholine (lyso-Pc) immediately induced an approximate 3-fold higher beta-galactosidase activity than the constitutive isozyme of untreated B lymphocytes. Thus, the lyso-Pc-inducible isozyme is not a de novo enzyme. Outer surface of mouse T lymphocytes carries constitutive (non-Neu-1) and inducible (Neu-1) sialidase isozymes. The lyso-Pc-inducible beta-galactosidase of B lymphocytes and the Neu-1 sialidase of T lymphocytes were required for conversion of vitamin D3-binding protein (Gc protein) to a potent macrophage activating factor. This enzymatic generation of the macrophage activating factor was mediated via enzyme-associated receptors.

Tumor necrosis factor release by murine macrophages stimulated by the cytotoxic ether lipid 1-O-hexadecyl-2-O-methyl-SN-glycero-3-phosphorylcholine (ET-18-O-OCH3)

The cytotoxic ether lipid 1-O-hexadecyl-2-O-methyl-SN-glycero-3-phosphorylcholine (ET-18-O-OCH3) is a structural analog of the mediator of inflammation platelet-activating factor (PAF). Recent studies demonstrated that ET-18-O-OCH3 activates human monocytes selectively at non-cytotoxic concentrations. The current studies determined the capacity of ET-18-O-OCH3 to stimulate release of TNF alpha by murine peritoneal macrophages. Macrophage receptors for ET-18-OCH3 and PAF were also assessed. ET-18-O-OCH3 and PAF stimulated TNF alpha release by resident BALB/c macrophages in the presence of LPS but not in the absence of this co-factor. In contrast, both ET-18-O_OCH3 and PAF stimulated TNF alpha release by thioglycollate-elicited macrophages in the absence of LPS although release was greater in the presence of this co-stimulus. Optimal stimulation of TNF alpha release occurred at 10(-14)-10(-11) M ET-18-O-OCH3 and PAF. Elicited macrophages and splenic macrophages from C57Bl/6 mice, unlike those from BALB/c mice, did not respond to 10(-15)-10(-8) M ET-18-O-OCH3 or PAF without or with LPS. Scatchard analysis of [3H]PAF binding to elicited BALB/c macrophages revealed the existence of high affinity receptors for PAF. In contrast, there was no evidence for receptors for ET-18-O-OCH3. ET-18-O-OCH3 did not compete with PAF for binding; macrophage activation by ET-18-O-OCH3 was not stereospecific; and, binding studies using [3H]ET-18-O-OCH3 did not reveal saturable binding characteristic of binding to specific receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Regulation of inflammation-primed activation of macrophages by two serum factors, vitamin D3-binding protein and albumin

A very small amount (0.0005 to 0.001%) of an ammonium sulfate [50% saturated (NH4)2SO4]-precipitable protein fraction of alpha 2-globulin efficiently supported inflammation-primed activation of macrophages. This fraction contains vitamin D3-binding protein essential for macrophage activation. Comparative macrophage activation studies with fetal calf serum, alpha 2-globulin fraction, 50% (NH4)2SO4 precipitate, and purified bovine vitamin D3-binding protein revealed that fetal calf serum and alpha 2-globulin fraction appear to contain an inhibitor for macrophage activation while ammonium sulfate precipitate contains no inhibitor. This inhibitor was found to be serum albumin. When bovine serum albumin (25 micrograms/ml) was added to a medium supplemented with 0.0005 to 0.05% (NH4)2SO4 precipitate or 1 to 10 ng of vitamin D3-binding protein per ml, activation of macrophages was inhibited.

In vivo and in vitro activation of macrophages with a cyanine photosensitizing dye, platonin

A cyanine photosensitizing dye, platonin, is a potent macrophage-activating agent. Four days after the administration to mice of small amounts of platonin (20-40 ng/mouse), peritoneal macrophages exhibited greatly enhanced Fc-receptor-mediated phagocytic and superoxide-generating capacities. Much higher doses (more than 3000 ng/mouse) did not have this effect. Photodynamic experiments for macrophage activation were performed by exposing mouse peritoneal cells (mixture of macrophages and B and T lymphocytes) to white fluorenscent light (3 J m-2s-1) in media containing various low concentrations of platonin. A short exposure to white fluorescent light (5 s, 15 J m-2) of peritoneal cells in a medium containing 3 ng platonin/ml produced a maximal level of phagocytic capacity of macrophages. Although platonin absorbs light poorly at wavelengths longer than 630 nm, the region of the spectrum in which the tissues are transparent allows reasonable penetration of light. Thus, we designed experiments in which peritoneal cells were exposed to a red fluorescent light (0.5 J m-2s-1). In a medium containing 10 ng platonin/ml with 15 J m-2 red light, a markedly enhanced ingestion activity of macrophages was observed. Photodynamic treatment of peritoneal macrophages alone did not activate macrophages. Thus, participation of nonadherent cells is required for photodynamic activation of macrophages, implying that a macrophage-activating factor is generated within the nonadherent cells and transmitted to macrophages.

Tumoricidal capacities of macrophages photodynamically activated with hematoporphyrin derivative

Four days after administration to mice of small amounts (30-600 ng/mouse) of hematoporphyrin derivative (HPD), peritoneal macrophages exhibited a greatly enhanced Fc-receptor mediated phagocytic capacity as assayed by ingestion activity of IgG-coated sheep erythrocytes. Much higher doses (greater than 3000 ng/mouse) did not have this effect. The peritoneal macrophages activated by administration of HPD have tumoricidal capacity for IgG-coated retinoblastoma cells. We then studied in vitro photodynamic activation of macrophages by white and red fluorescent light irradiation of mouse peritoneal cells (mixture of macrophages and B and T lymphocytes) in media containing very low concentrations of HPD. A short (5 s) white fluorescent light exposure (1Wm-2) of peritoneal cells in a medium containing 0.03 ng HPD/mL produced the maximal level of ingestion activity of macrophages. A 15 s red fluorescent light exposure (1Wm-2) of peritoneal cells in a medium containing 0.1 ng HPD/mL produced the maximal level of ingestion activity of macrophages. Thus, photodynamic activation of macrophages with white fluorescent light is more efficient than that with red fluorescent light. This can be explained by the fact that HPD has a large absorption peak at about 364 nm which extends into the visible range, and decreasingly smaller absorption bands at 500, 535, 570 and 630 nm. In vitro photodynamically activated macrophages showed efficient tumoricidal activity regardless of the type (white or red) of light used. These results suggest that a low level of HPD promotes therapeutic immunopotentiation.

Anti-neoplastic action of peritoneal macrophages following oral administration of ether analogues of lysophospholipids

Inflamed lesions of normal and cancerous tissues induce activation of phospholipase A in plasma membranes resulting in the release of various decomposed products of membranous lipids. Oral administration in mice of dodecylglycerol (DDG), a synthetic alkyglycerol, and an alkyl ether analogue of lysophospholipids, 1-0-octadecyl-2-0-methyl-rac-glycero-3-phosphocholine (ET-18-OCH3-choline) efficiently activated peritoneal macrophages for enhanced Fc-mediated (fragment crystallisable) ingestion of red blood cells and direct cytotoxic action on retinoblastoma tumour cells. The activated macrophages not only inhibited tumour cell growth, but also markedly induced cytolysis of tumour cells. The antitumour capability of the macrophages was substantiated by luminol-enhanced chemiluminescence. These findings suggest that dodecylglycerol and ET-18-OCH3-choline administered orally retain their ability to induce a high level of macrophage activation and tumour cytotoxicity, just as occurs with intraperitoneal administration. Thus, these compounds have potential practical application in chemotherapy and immunotherapy of the tumour, which could be accomplished by simple oral rather than parenteral administration.

Regulation of neuronal differentiation in neuron-enriched primary cultures from embryonic rat cerebra by platelet activating factor and the structurally related glycerol ether lipid, dodecylglycerol

Primary cultures enriched in neurons dissociated from embryonic rat cerebra were used to demonstrate that platelet activating factor and the structurally related ether glycerolipid, dodecylglycerol, are readily taken up in small amounts by neurons and that they stimulate the differentiation of neurons. The stimulation of neuronal differentiation was observed as a precocious development of axon-like extensions which correlated with a concentration-dependent increase in neuronal-specific enzyme activities. This stimulation of morphological and neurochemical factors by either platelet activating factor or dodecylglycerol was almost completely abolished by triazolam, a known inhibitor of platelet activating factor function. Neither platelet activating factor nor dodecylglycerol at the concentrations used to achieve stimulation of neuronal differentiation compromised the plasma membrane, as indicated by the lack of leakage of cytoplasmic lactic acid dehydrogenase.

Vitamin D3 binding protein (group-specific component) is a precursor for the macrophage-activating signal factor from lysophosphatidylcholine-treated lymphocytes

A brief (30 min) treatment of mouse peritoneal cells (mixture of nonadherent lymphocytes and adherent macrophages) with 1-20 micrograms of lysophosphatidylcholine (lyso-PC) per ml in serum-supplemented RPMI medium 1640, followed by a 3-hr cultivation of the adherent cells alone, results in a greatly enhanced Fc receptor-mediated phagocytic activity of macrophages. This rapid process of macrophage activation was found to require a serum factor, the vitamin D3 binding protein (the human protein is known as group-specific component; Gc). Efficient activation of macrophages was achieved by using medium containing purified human Gc protein. Analysis of intercellular signal transmission among nonadherent (B and T) cells revealed that lyso-PC-treated B cells modify Gc protein to yield a proactivating factor, which can be converted by T cells to the macrophage-activating factor. This rapid generation process of the macrophage-activating factor was also demonstrated by stepwise incubation of Gc protein with lyso-PC-treated B-cell ghosts and untreated T-cell ghosts, suggesting that Gc protein is modified by preexisting membranous enzymes to yield the macrophage-activating factor. Incubation of Gc protein with a mixture of beta-galactosidase and sialidase efficiently generated the macrophage-activating factor. Stepwise incubation of Gc protein with B- or T-cell ghosts and sialidase or beta-galactosidase revealed that Gc protein is modified by beta-galactosidase of B cells and sialidase of T cells to yield the macrophage-activating factor. Administration to mice of a minute amount (4-10 pg per mouse) of in vitro, enzymatically generated macrophage-activating factor resulted in a greatly enhanced (3- to 7-fold) ingestion activity of macrophages.

A serum factor for macrophage activation after in vitro dodecylglycerol treatment of mouse lymphocytes

Alkylglycerols, inflammation products of cancerous tissues, are potent macrophage activating agents. A brief in vitro treatment (30 min) of mouse peritoneal cells with a low concentration (50 ng/mL) of dodecylglycerol (DDG) in 10% foetal calf serum supplemented RPMI-1640 medium (FCS medium) activates macrophages for Fc-receptor mediated ingestion activity. A serum factor(s) was shown to be required for the activation of macrophages. When non-adherent cells were treated with rac-sn-1(3)-dodecylglycerol (DDG) in a serum free-0.1% egg albumin supplemented RPMI medium (EA medium) for 30 min and cultured in FCS medium for 2 h, the resultant conditioned medium contained a signal factor able to activate macrophages (macrophage activating factor). A conditioned medium prepared with electrophoresed serum alpha 2-globulin fraction in EA medium markedly enhanced activation of macrophages. Incubation of DDG-treated non-adherent cell ghosts in EA medium containing alpha 2-globulin also produced the macrophage activating signal factor. Therefore, it is concluded that a serum factor in alpha 2-globulin fraction is processed by pre-existing functions or enzymes of DDG-treated non-adherent cell membrane to yield a macrophage activating signal factor.

Activation process of macrophages after in vitro treatment of mouse lymphocytes with dodecylglycerol

Alkylglycerols, inflammation products of cancerous membrane lipids, efficiently activate macrophages. A brief in vitro treatment (30 min) of peritoneal cells (mixture of non-adherent and adherent cells) with a small amount (50 ng/ml) of synthetic dodecylglycerol (DDG) resulted in greatly enhanced Fc-receptor-mediated ingestion activity of macrophages. However, treatment of adherent cells (macrophages) alone with DDG produced no significant enhancement of macrophage ingestion activity, implying that macrophage activation requires a contribution of non-adherent cells. DDG-treated non-adherent cells were found to generate a macrophage-activating signal factor. Studies with a serum free-0.1% egg albumin-supplemented RPMI 1640 medium revealed that a serum factor is essential for macrophage activation process. Time course analysis of stepwise transfers of conditioned media of DDG-treated or untreated B cells and T cells revealed that DDG-treated B cells rapidly transmit a factor to untreated T cells which yield the ultimate macrophage-activating factor. This signal transmission among these cells for the macrophage activation process is too rapid to allow time for synthesis of inducible gene products. Thus, we hypothesized that a serum factor is modified by the pre-existing function of DDG-treated B cells and further modified by the pre-existing function of untreated T cells to yield macrophage-activating factor. This hypothesis was confirmed by the demonstration that DDG-treated splenic non-adherent cell ghosts modify a serum factor to yield macrophage-activating factor.