Astasian: A new stimulator of peritoneal macrophages

Immunological properties of astasin, a novel substance isolated from Astasia longa was studied. 3-4 days after intraperitoneal administration of astasin in a dose of 1000 micrograms per a mouse (50 mg/kg) in the form of suspension in physiological solution or gel in dimethylsulfoxide there was observed maximum increase in the number of the Fc-receptor cells of the macrophage plasmatic membranes and intensity of sheep red blood cell phagocytosis (3.6-4 and 3.2-4-fold, respectively). Dimethylsulfoxide solution of astasin increased migration of the cells into the abdominal cavity by 5.8 times. The respective figure for the astasin suspension was 28. times. Therefore, differences in the nature of the effect and quantitative indices after the exposure to astasin in the above two forms were observed. Sodium chloride isotonic solution of astasin had a retarded but more prolonged effect on the macrophages which was probably due to gradual digestion of the polysaccharide phagocyted granules by the macrophages.     

HDL-associated PAF-AH reduces endothelial adhesiveness in apoE-/- mice.

Macrophage infiltration into the subendothelial space at lesion prone sites is the primary event in atherogenesis. Inhibition of macrophage homing might therefore prevent atherosclerosis. Since HDL levels are inversely correlated with cardiovascular risk, their effect on macrophage homing was assessed in apoE-deficient (apoE-/-) mice. Overexpression of human apolipoprotein AI in apoE-/- mice increased HDL levels 3-fold and reduced macrophage accumulation in an established assay of leukocyte homing to aortic root endothelium 3.2-fold (P<0.005). This was due to reduced in vivo betaVLDL oxidation, reduced betaVLDL triggered endothelial cytosolic Ca2+ signaling through PAF-like bioactivity, lower ICAM-1 and VCAM-1 expression, and diminished ex vivo leukocyte adhesion. Adenoviral gene transfer of human PAF-acetylhydrolase (PAF-AH) in apoE-/- mice increased PAF-AH activity 1.5-fold (P<0.001), reduced betaVLDL-induced ex vivo macrophage adhesion 3.5-fold (P<0.01), and reduced in vivo macrophage homing 2.6-fold (P<0.02). These inhibitory effects were observed in the absence of increased HDL cholesterol levels. In conclusion, HDL reduces macrophage homing to endothelium by reducing oxidative stress via its associated PAF-AH activity. This protective mechanism is independent of the function of HDL as cholesterol acceptor. Modulation of lipoprotein oxidation by PAF-AH may prevent leukocyte recruitment to the vessel wall, a key feature in atherogenesis.     

Effects of deletion of macrophage ABCA7 on lipid metabolism and the development of atherosclerosis in the presence and absence of ABCA1

ABCA7, a close relative of ABCA1 which facilitates cholesterol efflux to lipid-poor apoproteins, has been implicated in macrophage lipid efflux and clearance of apoptotic cells in in vitro studies. In the current study, we investigated the in vivo effects of macrophage ABCA7 deficiency on lipid metabolism and atherosclerosis. Chimeras with dysfunctional ABCA7 in macrophages and other blood cells were generated by transplantation of bone marrow from ABCA7 knockout (KO) mice into irradiated low-density lipoprotein receptor (LDLr) KO mice. Unexpectedly, macrophage ABCA7 deficiency did not significantly affect atherosclerosis susceptibility of LDLr KO mice after 10 weeks Western-type diet feeding. However, ABCA7 deficiency was associated with 2-fold (p<0.05) higher macrophage ABCA1 mRNA expression levels. Combined disruption of ABCA1 and ABCA7 in bone-marrow-derived cells increased atherosclerotic lesion development (1.5-fold (p>0.05) as compared to wild type transplanted mice. However, single deletion of ABCA1 had a similar effect (1.8-fold, p<0.05). Macrophage foam cell accumulation in the peritoneal cavity was reduced in ABCA1/ABCA7 dKO transplanted animals as compared to single ABCA1 KO transplanted mice, which was associated with increased ABCG1 expression. Interestingly, spleens of ABCA1/ABCA7 double KO transplanted mice were significantly larger as compared to the other 3 groups and showed massive macrophage lipid accumulation, a reduction in CD3+ T-cells, and increased expression of key regulators of erythropoiesis. In conclusion, deletion of ABCA7 in bone marrow-derived cells does not affect atherogenesis in the arterial wall neither in the absence or presence of ABCA1. Interestingly, combined deletion of bone marrow ABCA1 and ABCA7 causes severe splenomegaly associated with cellular lipid accumulation, a reduction in splenic CD3+ T cells, and induced markers of erythropoeisis. Our data indicate that ABCA7 may play a role in T cell proliferation and erythropoeisis in spleen.     

Role of porin of Shigella dysenteriae type 1 in modulation of lipopolysaccharide mediated nitric oxide and interleukin-1 release by murine peritoneal macrophages

The ability of Shigella dysenteriae type 1 porin to induce the release of nitric oxide (NO) and interleukin-1 (IL-1) from peritoneal macrophages of mouse and to regulate lipopolysaccharide (LPS) and gamma interferon (IFN-gamma) mediated release of the two proinflammatory mediators was investigated. Porin released nitrite when added to macrophage cultures. A maximum of 3.2-fold nitrite release by macrophages was observed with 100 ng ml(-1) of porin. The nitrite release of LPS was enhanced significantly by lower concentrations of porin, whereas the effect of IFN-gamma was enhanced by porin at higher concentrations. Polysaccharide (PS) moiety of LPS stimulated the nitrite release of elicited macrophages by 1.6-fold compared to untreated control. It also enhanced the stimulatory effect of 1 and 10 ng ml(-1) of porin by 1.3-fold. Lipid A (LPA) moiety of LPS did not release nitrite, nor did it increase the porin mediated nitrite production. Porin treated 24 h old macrophage culture supernatants were applied for ConA activated thymocyte proliferation as a measure for determination of IL-1 release. Sixty percent depletion of thymocyte proliferation was observed when the porin treated macrophage supernatants were absorbed with anti-IL-1 antibody. A maximum of 5.5-fold increase of thymocyte proliferation over control was found with 1 and 10 ng ml(-1) of porin. One or 10 ng ml(-1) of porin and LPS augmented the thymocyte growth, 1.5-fold beyond that obtained by porin and 1.8-/1. 7-fold more than that obtained by LPS, alone. Similarly, porin and IFN-gamma co-stimulated the cell growth also. PS enhanced the thymocyte proliferation by 5-fold. It also enhanced the thymocyte growth by co-stimulating 1.4-fold the effect observed by 1 or 10 ng ml(-1) of porin alone. LPA could not participate in the cell proliferating activity nor did it enhance the stimulatory effect of porin. Therefore, both nitrite release and thymocyte proliferation by LPS could be substituted by PS only. The tight association of the two bacterial outer membrane components, porin and LPS, could be a necessary co-signal for boosting the release of the two proinflammatory mediators, namely NO and IL-1, which may be associated with the inflammatory response of the colon during Shigella invasion.     

Leishmania panamensis: comparative inhibition of nuclear DNA topoisomerase II enzymes from promastigotes and human macrophages reveals anti-parasite selectivity of fluoroquinolones, flavonoids and pentamidine

Certain model inhibitors exerted selective action against the catalytic activity of nuclear DNA topoisomerase II (TOPII) of Leishmania panamensis promastigotes. The second-generation fluoroquinolones enoxacin and ciprofloxacin exhibited extraordinarily high anti-parasite selectivity displaying 582- and 40-fold greater potencies against L. panamensis TOPII as compared with the human macrophage enzyme. The flavonoids quercetin and ellagic acid showed inverse specificities, the former being 161-fold more potent against L. panamensis TOPII, and the latter 15.7-fold more active against macrophage TOPII. The protoberberine coralyne was a potent inhibitor of both Leishmania and macrophage TOPII. Bis-benzimidazoles and the diamidine diminazene aceturate exhibited uniformly high potencies against parasite and host TOPII, but a second diamidine pentamidine showed 17.6-fold greater specificity for Leishmania TOPII. The antimonial sodium stibogluconate was an ineffective inhibitor of parasite TOPII showing 4.3-fold greater potency against the macrophage enzyme. These findings suggest that the leishmanicidal activities of certain fluoroquinolones and pentamidine may be mediated partly through TOPII inhibition.     

The effect of human recombinant macrophage colony-stimulating factor (CSF-1) on the murine mononuclear phagocyte system in vivo

Human recombinant macrophage CSF (CSF-1) was administered i.v. to mice. After four daily injections there was a dose-dependent increase in the responsiveness of bone marrow cells from the treated animals to CSF-1 in vitro. At the highest dose tested (20,000 U/day) there was a selective 10-fold increase in the circulating population of mature monocytes. CSF-1 treatment also increased the macrophage content of the liver and peritoneal cavity and caused splenomegaly. The macrophages isolated from the peritoneum of CSF-1-treated animals were larger and expressed higher levels of the macrophage-specific F4/80 Ag. These data demonstrate that CSF-1 can act as a circulating regulator of the mononuclear phagocyte system.     

Adipocyte enhancer-binding protein 1 (AEBP1) (a novel macrophage proinflammatory mediator) overexpression promotes and ablation attenuates atherosclerosis in ApoE (-/-) and LDLR (-/-) mice

Atherogenesis is a long-term process that involves inflammatory response coupled with metabolic dysfunction. Foam cell formation and macrophage inflammatory response are two key events in atherogenesis. Adipocyte enhancer-binding protein 1 (AEBP1) has been shown to impede macrophage cholesterol efflux, promoting foam cell formation, via peroxisome proliferator-activated receptor (PPAR)-γ1 and liver X receptor α (LXRα) downregulation. Moreover, AEBP1 has been shown to promote macrophage inflammatory responsiveness by inducing nuclear factor (NF)-κB activity via IκBα downregulation. Lipopolysaccharide (LPS)-induced suppression of pivotal macrophage cholesterol efflux mediators, leading to foam cell formation, has been shown to be mediated by AEBP1. Herein, we showed that AEBP1-transgenic mice (AEBP1(TG)) with macrophage-specific AEBP1 overexpression exhibit hyperlipidemia and develop atherosclerotic lesions in their proximal aortas. Consistently, ablation of AEBP1 results in significant attenuation of atherosclerosis (males: 3.2-fold, P = 0.001 [en face]), 2.7-fold, P = 0.0004 [aortic roots]; females: 2.1-fold, P = 0.0026 [en face], 1.7-fold, P = 0.0126 [aortic roots]) in the AEBP1(-/-)/low-density lipoprotein receptor (LDLR )(-/-) double-knockout (KO) mice. Bone marrow (BM) transplantation experiments further revealed that LDLR (-/-) mice reconstituted with AEBP1(-/-)/LDLR (-/-) BM cells (LDLR (-/-)/KO-BM chimera) display significant reduction of atherosclerosis lesions (en face: 2.0-fold, P = 0.0268; aortic roots: 1.7-fold, P = 0.05) compared with control mice reconstituted with AEBP1(+/+)/LDLR (-/-) BM cells (LDLR (-/-)/WT-BM chimera). Furthermore, transplantation of AEBP1(TG) BM cells with the normal apolipoprotein E (ApoE) gene into ApoE (-/-) mice (ApoE (-/-)/TG-BM chimera) leads to significant development of atherosclerosis (males: 2.5-fold, P = 0.0001 [en face], 4.7-fold, P = 0.0001 [aortic roots]; females: 1.8-fold, P = 0.0001 [en face], 3.0-fold, P = 0.0001 [aortic roots]) despite the restoration of ApoE expression. Macrophages from ApoE (-/-)/TG-BM chimeric mice express reduced levels of PPARγ1, LXRα, ATP-binding cassette A1 (ABCA1) and ATP-binding cassette G1 (ABCG1) and increased levels of the inflammatory mediators interleukin (IL)-6 and tumor necrosis factor (TNF)-α compared with macrophages of control chimeric mice (ApoE (-/-)/NT-BM ) that received AEBP1 nontransgenic (AEBP1(NT) ) BM cells. Our in vivo experimental data strongly suggest that macrophage AEBP1 plays critical regulatory roles in atherogenesis, and it may serve as a potential therapeutic target for the prevention or treatment of atherosclerosis.     

Modulation of the biological activity of bacterial endotoxin by incorporation into liposomes

In an attempt to define the mechanism by which endotoxin induces its biological activity, we studied the effect of the incorporation of lipopolysaccharide and lipid A into phospholipid vesicles (liposomes) on the stimulation of the macrophage cell-line RAW 264.7 and on the coagulation of Limulus amoebocyte lysate. The incorporation of Salmonella minnesota smooth-and rough (Re) lipopolysaccharide or primarily monophosphoryl lipid A into multilamellar and small unilamellar vesicles consisting of phosphatidylcholine, phosphatidylserine and cholesterol (molar ratio 4:1:4) reduced the interleukin 1 inducing potency of these substances about 1000-fold. When corrected for the actual uptake of radiolabeled free and liposome-incorporated lipopolysaccharide by the cells, this difference amounted to 100- to 1000-fold. In addition, liposome-associated Re-lipopolysaccharide was about 1000-fold less potent in stimulating the Fc-receptor mediated uptake of IgG-coated sheep erythrocytes by the cells. The ability of lipopolysaccharide and lipid A to coagulate the Limulus amoebocyte lysate appeared to be at least 100-fold decreased upon incorporation into phospholipid vesicles. Control experiments demonstrated that liposomes prepared without lipopolysaccharide did not reduce the studied activities of free lipopolysaccharide. In conclusion, the incorporation of lipopolysaccharide into the liposomal membrane probably prevents the interaction of the hydrophobic portion of the lipid A component of lipopolysaccharide with the plasma-membrane structures involved in the activation of macrophages and with the proteins of the Limulus amoebocyte lysate. This indicates that the direct interaction of the lipid A moiety of lipopolysaccharide with the macrophage plasma-membrane is required to optimally trigger the studied responses.     

Differential effects of the novel non-peptidic opioid 4-tyrosylamido-6-benzyl-1,2,3,4 tetrahydroquinoline (CGPM-9) on in vitro rat t lymphocyte and macrophage functions

Opioid receptors have been reported on immune cells of several species and shown to subserve effector functions of these cell types. Mu-selective opioid agonists such as morphine are immunosuppressive, whereas certain delta-opioid receptor-selective agonists have been associated with immunopotentiation. We have previously shown that intracerebroventricular administration of the non-peptidic delta-opioid receptor agonists did not alter certain parameters of immunocompetence. In this study, we evaluated the in vitro effects of the novel non-peptidic opioid 4-tyrosylamido-6-benzyl-1,2,3,4 tetrahydroquinoline (CGPM-9) on lymphocyte and macrophage functions. We demonstrated that CGPM-9 enhanced rat thymic lymphocyte proliferative response to concanavalin A (2.85- to 5.5-fold increases), and suppressed LPS-induced nitric oxide (67 to 72 percent reduction) and TNF-alpha production (46 percent reduction) by peritoneal macrophages, compared with untreated control. The mu-opioid receptor selective antagonist CTOP used at equimolar doses, significantly suppressed the effect of CGPM-9 on lymphocyte and macrophage functions (CTOP alone did not show any effect on lymphocyte or macrophage functions). In summary, CGPM-9 activated thymic lymphocyte proliferation and suppressed macrophage functions by acting at mu-opioid receptors. This suggests that opioid receptors on immunocytes may be coupled to different signaling pathways depending on the cell type and effector function being analyzed. The mechanism (s) associated with the differential effect of CGPM-9 on these immune cells remains to be elucidated. The pharmacotherapeutic potential for compounds such as CGPM-9 which potentiate T lymphocyte proliferation and suppress production of macrophage-derived inflammatory cytokines is substantial in research and clinical medicine.     

Helianthus tuberosus agglutinin directly induces neutrophil migration, which can be modulated/inhibited by resident mast cells.

We investigated the effect of Helianthus tuberosus agglutinin (HTA) on neutrophil migration in vivo and in vitro. The role of resident cells in this effect was analyzed. Peritonitis was induced by injecting stimuli into rat (150-200 g) peritoneal cavities, and in vitro neutrophil chemotaxis was performed using a Boyden microchamber. HTA (80, 200, or 500 microg/mL per cavity) induced significant in vivo neutrophil migration (p < 0.05); in vitro assays showed that this lectin also induced neutrophil chemotaxis, an effect inhibited by the incubation of lectin associated with alpha-D(+)-mannose, its specific binding sugar. Depletion of the resident-cell population by peritoneal lavage did not alter HTA-induced neutrophil migration (200 microg/mL per cavity). The opposite strategy, increasing peritoneal macrophages by intraperitoneally injecting rats with thioglycollate, did not enhance the neutrophil migration produced by HTA (200 microg/mL per cavity). In addition, injection of supernatant from HTA-stimulated macrophage culture (300 microg/mL) into rat peritoneal cavities did not induce neutrophil migration. However, reduction of the peritoneal mast-cell population potentiated the neutrophil migration (p < 0.05) induced by HTA (200 microg/mL per cavity). Lectin from H. tuberosus has a direct neutrophil chemotatic effect that is modulated by mast cells.     

Development of haematopoietic colonies on the macrophage layer formed in the peritoneal cavity of S1/S1d mice

The colony-forming ability of haematopoietic cells was examined on the macrophage layer formed in the peritoneal cavity of S1/S1d mice. The bone marrow cells of the congenic +/+ mice formed many macroscopic colonies on the macrophage layer of the S1/S1d mice although they did not form macroscopic colonies in the spleens of the same S1/S1d recipients. The size and the differentiation pattern of colonies on the macrophage layer of the S1/S1d mice were comparable to those of the colonies on the macrophage layer of the +/+ mice. There are two possible explanations for these results: (a) The microenvironmental defect of the S1/S1d mice has a more prominent effect on the development of spleen colonies than that of macrophage-layer colonies because 'Steel' locus may not be expressed significantly in the peritoneal macrophages or (b) because the cells that make colonies on the macrophage layer may be more differentiated cells than the multipotential stem cells that make colonies in the spleen.     

Enhancement of macrophage immune and nonimmune receptor-mediated phagocytosis by a low molecular weight soluble factor from resident thymocytes

Macrophage phagocytic activity is regulated in part by products of activated T lymphocytes. We previously reported that a heat-stable soluble factor derived from resident (nonactivated) thymocytes increases murine peritoneal macrophage Fc-dependent phagocytosis. In the present study, we further investigate the effect of the thymocyte factor on immune and nonimmune receptor-mediated phagocytosis, Fc receptor expression, and its approximate m.w. After 4 days of incubation, cellfree thymocyte supernatant produced a mean (three experiments) 2.10-, 2.08-, and 1.97-fold increase in macrophage phagocytosis of C3-, IgG-, and tannic acid-treated erythrocytes, respectively. Macrophage IL 1 production was not enhanced by a similar concentration of thymocyte supernatant. The thymocyte factor(s) increased the number of IgG2a Fc receptors (FcRI) from 2.4 x 10(5) to 3.8 x 10(5) receptor sites per macrophage. The number of Fc receptors that bind IgG1 and IgG2b (FcRII) was not altered. The soluble factor(s) that increased Fc-mediated phagocytosis passed through both 6000- to 8000-dalton and 2000-dalton cutoff dialysis membranes and eluted from a Sephadex G-25 Fine column over a m.w. range of 200 to 1000 daltons, with a peak activity at 450 daltons. These data suggest that resident thymocytes enhance macrophage phagocytosis of opsonized and nonopsonized particles through the elaboration of a low m.w. substance(s).     

Activation of proteinase-activated receptor-2 in mesothelial cells induces pleural inflammation

Pleural inflammation underlies many pleural diseases, but its pathogenesis remains unclear. Proteinase-activated receptor-2 (PAR(2)) is a novel seven-transmembrane receptor with immunoregulatory roles. We hypothesized that PAR(2) is present on mesothelial cells and can induce pleural inflammation. PAR(2) was detected by immunohistochemistry in all (19 parietal and 11 visceral) human pleural biopsies examined. In cultured murine mesothelial cells, a specific PAR(2)-activating peptide (SLIGRL-NH(2)) at 10, 100, and 1,000 muM stimulated a 3-, 42-, and 1,330-fold increase of macrophage inflammatory protein (MIP)-2 release relative to medium control, respectively (P < 0.05 all) and a 2-, 32-, and 75-fold rise over the control peptide (LSIGRL-NH(2), P < 0.05 all). A similar pattern was seen for TNF-alpha release. Known physiological activators of PAR(2), tryptase, trypsin, and coagulation factor Xa, also stimulated dose-dependent MIP-2 release from mesothelial cells in vitro. Dexamethasone inhibited the PAR(2)-mediated MIP-2 release in a dose-dependent manner. In vivo, pleural fluid MIP-2 levels in C57BL/6 mice injected intrapleurally with SLIGRL-NH(2) (10 mg/kg) were significantly higher than in mice injected with LSIGRL-NH(2) or PBS (2,710 +/- 165 vs. 880 +/- 357 vs. 88 +/- 46 pg/ml, respectively; P < 0.001). Pleural fluid neutrophil counts were higher in SLIGRL-NH(2) group than in the LSIGRL-NH(2) and PBS groups (by 40- and 26-fold, respectively; P < 0.05). This study establishes that activation of mesothelial cell PAR(2) potently induces the release of inflammatory cytokines in vitro and neutrophil recruitment into the pleural cavity in vivo.     

发酵灵芝菌粉抑制小鼠肿瘤及对正常小鼠免疫功能影响的研究

研究了发酵灵芝菌粉对接种S-180瘤细胞后的实验小鼠肿瘤的抑制作用、发酵灵芝菌粉对正常的实验小鼠腹腔巨噬细胞吞噬能力以及脾脏自然杀伤细胞活性的影响,结果表明发酵灵芝菌粉对小鼠移植性肿瘤的生长有明显的抑制作用,但对正常小鼠腹腔巨噬细胞吞噬能力以及脾脏自然杀伤细胞的活性无明显的免疫促进作用。     

The antiinflammatory effects of essential fatty acid deficiency in experimental glomerulonephritis. The modulation of macrophage migration and eicosanoid metabolism

Dietary polyunsaturated fatty acid modulation exerts a beneficial effect in immune-mediated glomerulonephritis. To elucidate the mechanisms underlying this phenomenon, the effects of essential fatty acid (EFA) deficiency on the heterologous phase of nephrotoxic nephritis in rats (induced by the injection of a rabbit antiglomerular basement membrane antibody) were studied. The heterologous phase of nephrotoxic nephritis was characterized by an invasion of leukocytes into the glomerulus. Polymorphonuclear neutrophils predominated early on (3 h), whereas macrophages predominated at 24 and 72 h. EFA deficiency selectively prevented the influx of macrophages into the glomerulus. The invasion of polymorphonuclear neutrophils, in contrast, was unaffected. The influx of leukocytes into the glomerulus during nephritis was accompanied by a marked enhancement (10- to 40-fold) in glomerular thromboxane and leukotriene B4 production. EFA deficiency largely attenuated this change. Renal dysfunction during the heterologous phase of nephritis was manifested as azotemia, polyuria, sodium retention, and proteinuria. With EFA deficiency, polyuria, azotemia, and sodium retention were not seen. Proteinuria was reduced by approximately 85%. To address whether the lack of macrophage migration into the glomerulus in the context of nephritis with EFA deficiency might be due to a functional defect in macrophage migration, the chemotactic responsiveness of EFA-deficient macrophages was examined. EFA-deficient macrophages displayed normal chemotactic migration toward activated C. In sum, EFA deficiency prevents the invasion of macrophages into the glomerulus in nephrotoxic nephritis and attenuates the accompanying metabolic and functional alterations, but does not affect macrophage chemotactic responsiveness. Alterations in macrophage elicitation and lipid mediator generation by inflamed glomeruli thus appear to be central to the salutary effect of dietary polyunsaturated fatty acid modification on glomerulonephritis.     

Pro-inflammatory effect of Arum maculatum lectin and role of resident cells

Arum maculatum agglutinin (AMA) is a monocot lectin isolated from tubers of Arum maculatum L. (Araceae) which exhibits different specificity towards oligo-mannosidic-type and N-acetyllactosaminic-type glycans. We have investigated the effect of this lectin on the cells of the immune system. Models of neutrophil migration in vivo, neutrophil chemotaxis in vitro and macrophage cultures were used to study the lectin inflammatory activity. When administered into rat peritoneal cavities, AMA (80, 200 and 500 microg/mL/cavity) induced significant and dose-dependent neutrophil migration. This effect was inhibited by incubation with alpha-methyl-d-mannoside. A 83% depletion in the number of resident cells following peritoneal lavage did not reduce the AMA-induced neutrophil migration, as compared to sham animals (not washed). However, pre-treatment with 3% thioglycolate which increases the peritoneal macrophage population by 236%, enhanced the neutrophil migration induced by AMA (200 microg/mL/cavity) (119%, p < 0.05). Reduction of peritoneal mast cell population by chronic treatment of cavities with compound 48/80 did not modify AMA-induced neutrophil migration. The neutrophil chemotaxy assay in vitro shows that the lectin (300 microg/mL) induces neutrophil chemotaxy (368% p < 0.05) compared to RPMI. Finally, injection into peritoneal cavities of supernatants from macrophage cultures obtained after stimulation with AMA (300 microg/mL) enhanced neutrophil migration (110% p < 0.05). Summarizing, our data suggest that A. maculatum agglutinin presents pro-inflammatory activity, inducing neutrophil migration by two ways, one which is independent on resident cells and another one dependent on the presence of these cells.     

The effect of inflammation on splenic colony formation after the intraperitoneal administration of bone marrow cells

The number of spleen colonies formed after intraperitoneal injection of bone marrow cells increases approximately 100-fold in mice with inflammation induced by nitrocellulose filters implanted into the intraperitoneal cavity. By transplanting these filters together with cells grown on them into intact animals and replacing them with clean filters we have demonstrated that this effect is associated with inflammation focus in the peritoneal cavity rather than with CFU-S proliferation of the filter surface.     

Enhanced chemotaxis of macrophages by strenuous exercise in trained mice: Thyroid hormones as possible mediators

Exercise modulates the macrophage activity via stress hormones. Three experiments were performed. (1) The effect of strenuous exercise performed by trained mice on macrophage chemotactic capacity was evaluated; (2) peritoneal macrophages from control mice were incubated with plasma from exercised mice or control mice and the differences in chemotaxis were measured; (3) changes in plasma T₃ and T₄ levels after exercise were measured, and the effect of incubation with the post-exercise levels of plasma T₃ and T₄ on chemotaxis was then studied in vitro. A 10⁴-fold higher concentration of each hormone was also evaluated. Exercise provoked an increase in chemotaxis (104 ± 35 vs. 47 ± 11 in controls). Incubation with plasma from exercised mice led to an increased level of chemotaxis. Incubation with concentrations of T₃ and T₄ similar to those observed in post-exercise plasma (T₃, 2.3 nmol l^-1; T₄, 84 nmol l^-1) enhanced chemotaxis with respect to incubation with the basal concentrations of the hormones in control animals. A 10M⁴-fold concentration of T₄ reversed this effect. It is concluded that thyroid hormones stimulate macrophage chemotaxis. Also, these data support the hypotheseis that thyroid hormones may be involved in exercise-induced stimulation of chemotaxis.