Phagocytic Function Of Macrophages Research Articles

A Non-invasive Technique to Measure Lipopolysaccharide (LPS)-Stimulated Macrophage Phagocytic Function

Introduction: Sepsis is the leading cause of death in critically ill patients in the United States. Clinical diagnosis of sepsis relies heavily on bacterial cultures and the manifestation of clinical signs. However, underlying biological changes of sepsis may occur hours to days before the clinical presentation of symptoms, therefore early detection of biological perturbations may provide crucial opportunities for early diagnosis and treatment of sepsis. Macrophages play a pivotal role in the early systemic response to infection by phagocytosis of microbes and augmentation of the host immune response, in liver and elsewhere.

Experiments on Antitumor Activity and Immunological Mechanisms of Scutellaria Barbata Polysaccharides

Abstract This research aimed at studying the antitumor activity and immunological mechanisms of Scutellaria barbata polysaccharides (SBPS). Hepatocarcinoma H22-bearing mice were randomly divided into negative control group, SPS group, and polyporus polysaccharide group. After the drug administration for 10 consecutive days, the inhibitory rate of tumors, thymus index, and spleen index, and the phagocytic function of macrophages were observed. ELISA method was used in the determination of the serum level of IL-2. The comparison was made among the groups. The results showed that SPS can effectively inhibit the growth of HepA. The inhibitory rate of tumors was 34.35%. The weight of immune organs was also increased among HepA-bearing mice. The serum level of IL-2 and the phagocytic function of macrophages were also increased. Thus, it can be concluded that SPS has obvious antitumor activity. The mechanism is due to the enhancement of the immune function.

Influence of joint exposure to diazinon, propoxur and bisphenol A on phagocytosis of RAW264.7 cell

To explore the toxicity of joint exposure to diazinon, propoxur and bisphenol A on phagocytosis. Flow cytometer was employed to detect the influence of diazinon and bisphenol A, propoxur and bisphenol A in mixture (mixed according to ratio of IC(50)) on mouse macrophage RAW264.7 cells' function to phagocyte fluorescent microspheres, adopting the percentage of phagocytic cells (PP) and the phagocytic index (PI) as measurement indicators. The final concentrations of mixture of diazinon and bisphenol A were (0.4 + 0.1), (3.6 + 0.7), (36.2 + 7.2), (43.4 + 8.7), (52.1 + 10.4), (62.5 + 12.5), (75.0 + 15.0) µg/ml; while those of mixture of propoxur and bisphenol A were (0.2 + 2.0 × 10(-2)), (2.4 + 0.2), (23.7 + 2.0), (35.6 + 3.0), (53.3 + 4.4), (80.0 + 6.7), (120.0 + 10.0) µg/ml. Then based on the dose-response relationship, a 2 × 2 factorial design was then carried out among different doses of mixture with statistical significance to statistically evaluate the interaction between diazinon and bisphenol A, propoxur and bisphenol A. After the joint exposure, compared to the control group (PP = (23.6 ± 2.2)%; PI = 0.36 ± 0.03), any dose of the mixture of diazinon and bisphenol A ((52.1 + 10.4), (62.5 + 12.5), (75.0 + 15.0) µg/ml) could significantly increase the levels of PP ((29.0 ± 1.4)%, t = 3.89, P < 0.05; (30.2 ± 2.3)%, t = 4.74, P < 0.05; (35.0 ± 3.4)%, t = 8.21, P < 0.05) and PI (0.43 ± 0.03, t = 3.86, P < 0.05; 0.41 ± 0.02, t = 2.95, P < 0.05; 0.46 ± 0.03, t = 5.34, P < 0.05); while that of propoxur and bisphenol A ((35.6 + 3.0), (53.3 + 4.4), (80.0 + 6.7), (120.0 + 10.0) µg/ml) reduced the levels of PP ((20.6 ± 1.1)%, t = -3.00, P < 0.05; (20.2 ± 1.0)%, t = -3.42, P < 0.05; (19.4 ± 1.3)%, t = -4.23, P < 0.05; (18.8 ± 2.1)%, t = -4.81, P < 0.05) and PI (0.31 ± 0.01, t = -4.75, P < 0.05; 0.31 ± 0.01, t = -4.58, P < 0.05; 0.30 ± 0.01, t = -4.92, P < 0.05; 0.27 ± 0.02, t = -7.80, P < 0.05) on the contrary. The 2 × 2 factorial design was carried out between the mixture of diazinon (60.0 µg/ml; PP = (28.5 ± 3.4)%; PI = 0.49 ± 0.07) and bisphenol A (12.0 µg/ml; PP = (35.7 ± 2.7)%; PI = 0.67 ± 0.07), and the mixture of propoxur (48.0 µg/ml ; PP = (28.1 ± 2.2)%; PI = 0.48 ± 0.04) and bisphenol A (4.0 µg/ml; PP = (34.4 ± 2.7)%; PI = 0.59 ± 0.07). The mixture of diazinon and bisphenol A (PP = (30.4 ± 1.4)%, F(interaction) = 6.22, P < 0.05; PI = 0.53 ± 0.03, F(interaction) = 7.35, P < 0.05) and the mixture of propoxur and bisphenol A (PP = (27.5 ± 4.1)%, F(interaction) = 4.56, P < 0.05; PI = 0.46 ± 0.08, F(interaction) = 11.13, P < 0.05) both showed a significant antagonistic interaction on phagocytosis of RAW264.7 cell. It is suggested that the interactions between diazinon & bisphenol A and propoxur & bisphenol A both played the antagonistic role on phagocytic function of macrophages in vitro.

HIV-1 transgene expression in rats induces differential expression of tumor necrosis factor alpha and zinc transporters in the liver and the lung

BackgroundHighly effective antiviral treatment can suppress HIV-1 infection, but the chronic effects of HIV-1-related viral proteins, including gp120 and Tat, on organs such as the lungs can be damaging. HIV-1 transgenic rodent models are useful for studying the systemic effects of these proteins independently of viral infection. We have previously shown that HIV-1 transgene expression (and therefore, HIV-1-related protein expression) in rats decreases alveolar macrophage zinc levels and phagocytic capacity by unknown mechanisms. We hypothesized that HIV-1 transgene expression induces chronic inflammation and zinc sequestration within the liver and thereby decreases zinc bioavailability in the lung. We examined the expression of the pro-inflammatory cytokine, tumor necrosis factor alpha (TNFα), the zinc storage protein, metallothionein (MT1), and the zinc exporter, ZNT1 in the livers and the lungs of wild type and HIV-1 transgenic rats ± dietary zinc supplementation. In addition, we measured zinc levels, the zinc importing protein ZIP1, and the phagocytic capacity in the alveolar macrophages.ResultsHIV-1 transgene expression increased the liver-specific expression of TNFα, suggesting a chronic inflammatory response within the liver in response to HIV-1-related protein expression. In parallel, HIV-1 transgene expression significantly increased MT1 and ZNT1 expression in the liver as compared to the lung, a pattern that is consistent with zinc sequestration in the liver as occurs during systemic inflammation. Further, HIV-1 transgene expression decreased intracellular zinc levels and increased expression of ZIP1 in the alveolar macrophages, a pattern consistent with zinc deficiency, and decreased their bacterial phagocytic capacity. Interestingly, dietary zinc supplementation in HIV-1 transgenic rats decreased gene expression of TNFα, MT1, and ZNT1 in the liver while simultaneously increasing their expression in the lung. In parallel, zinc supplementation increased alveolar macrophage intracellular zinc levels and bacterial phagocytic capacity in HIV-1 transgenic rats.ConclusionTaken together, these findings suggest that chronic HIV-1-related protein expression causes liver inflammation and zinc sequestration, which in turn limits zinc bioavailability in the lung and thereby impairs alveolar macrophage phagocytic function. Importantly, dietary zinc supplementation decreases liver inflammation and zinc sequestration and restores alveolar macrophage phagocytic function in HIV-1 transgenic rats, a result with potential clinical implications for improving lung health in HIV-1-infected individuals.

Lipid signaling in the atherogenesis context

Normally macrophages localized in the arterial vessel wall perform the "reverse transfer" of cholesterol, which includes endocytosis of low density lipoproteins (LDL), cholesterol transfer to newly formed high density lipoprotein particles, and their following elimination by the liver. The homeostatic function of macrophages for cholesterol involves a system of lipid sensors. Oxysterol sensors LXRs, oxysterol and cholesterol sensors INSIG and SCAP acting through controlled transcription factors SREBP, as well as sensors for oxidized fatty acids and their derivatives, PPAR, are the best studied. Activation of LXR and PPAR is also accompanied by inhibition of macrophage functions related to inflammation. Accumulation of oxidized and otherwise modified LDL in the subendothelial space induced by endothelium injury, infection, or other pathogenic factors instead of stimulation of the homeostatic functions of macrophages leads to their weakening with a concurrent increase in the inflammatory potential of these cells. These shifts seem to drive the transformation of macrophages into foam cells, which form the core of sclerotic plaques. The intervention of another lipid sensor, TLR4, can trigger such a radical change in the functional activity of macrophages. The interaction of modified LDL with this signaling receptor results in inhibition of the homeostatic oxysterol signaling, induction of additional LDL transporters, and activation of the phagocytic function of macrophages. The re-establishment of cholesterol homeostasis under these circumstances can be achieved by administration of LXR and PPARgamma agonists. Therefore, it is urgent to design ligands with reduced side effects.

Effects of the Aidi Dripping Pills on Immune Functions of the Tumor-bearing Mouse

To study the effects of Aidi Dripping Pills on immune functions of the tumor-bearing mouse on the basis of the previous experimental studies on its tumor-inhibiting and life-prolonging effects. By using the transplantation tumor mouse models, the effects of Aidi Dripping Pills on the lymphocyte transformation rate and the hemolysin formation in the S180 tumor-bearing mice, and on the phagocytic function of macrophages in the abdominal cavity of H22 tumor-bearing mice were investigated. In the 2.25 g/kg and 1.125 g/kg Aidi Dripping Pills groups, the lymphocyte transformation rates in the S180 tumor-bearing mice were significantly higher than that of the control group (P<0.01). In all the Aidi Dripping Pills groups, HC50 significantly increased (P<0.01 or P<0.05), carbon granular clearance significantly raised, and both the phagocytic index and phagocytic coefficient were significantly higher than those in the control group (P<0.01 or P<0.05). The Aidi Dripping Pills can significantly increase the cellular immune function, the humoral immune function and the phagocytic function of the mononuclear-macrophages, so it may show anti-tumor effects by enhancing the function of the reticuloendothelial system.

Delayed neonatal lung macrophage differentiation in a mouse model of in utero ethanol exposure

We have previously demonstrated that fetal ethanol exposure deranges the function and viability of the neonatal alveolar macrophage. Although altered differentiation of the alveolar macrophage contributes to pulmonary disease states within the adult lung, the effects of fetal ethanol exposure on the normal differentiation of interstitial to alveolar macrophage in the newborn lung are unknown. In the current study, using a mouse model of fetal ethanol exposure, we hypothesized that altered terminal differentiation of the neonatal interstitial to alveolar macrophage contributes to the observed cellular dysfunction in the ethanol-exposed newborn mouse. Control alveolar macrophage differentiation was characterized by increased expression of CD32/CD11b (P < or = 0.05) and increased in vitro phagocytosis of Staphylococcus aureus (P < or = 0.05) compared with interstitial macrophage. After in utero ethanol exposure, both alveolar and interstitial macrophage lacked the acquisition of CD32/CD11b (P < or = 0.05) and displayed impaired in vitro phagocytosis (P < or = 0.05). Ethanol significantly increased transforming growth factor-beta(1) (TGF-beta(1)) in the bronchoalveolar lavage fluid (P < or = 0.05), as well as in both interstitial and alveolar macrophages (P < or = 0.05). Oxidant stress contributed to the ethanol-induced changes on the interstitial and alveolar cells, since maternal supplementation with the glutathione precursor S-adenosylmethionine during ethanol ingestion normalized CD32/CD11b (P < or = 0.05), phagocytosis (P < or = 0.05), and TGF-beta(1) in the bronchoalveolar lavage fluid and macrophages (P < or = 0.05). Contrary to our hypothesis, fetal ethanol exposure did not solely impair interstitial to alveolar macrophage differentiation. Rather, fetal ethanol exposure impaired both neonatal interstitial and alveolar macrophage phagocytic function and differentiation. Increased oxidant stress and elevated TGF-beta(1) contributed to the impaired differentiation of both interstitial and alveolar macrophage.

Alteration of Toll-like receptor 4 activation by 4-hydroxy-2-nonenal mediated by the suppression of receptor homodimerization

Toll-like receptors (TLRs) detect invading microbial pathogens and initiate immune responses as part of host defense mechanisms. They also respond to host-derived substances released from injured cells and tissues to ensure wound healing and tissue homeostasis. Dysregulation of TLRs increases the risk of chronic inflammatory diseases and immune disorders. Inflammatory events are often accompanied by oxidative stress, which generates lipid peroxidation products such as 4-hydroxy-2-nonenal (4-HNE). Therefore, we investigated if 4-HNE affects TLR activation. We found that 4-HNE blocked LPS (a TLR4 agonist)-induced activation of NFκB and IRF3 as well as expression of IFNβ, IP-10, RANTES, and TNFα. To investigate the mechanism of inhibition by 4-HNE, we examined its effects on TLR4 dimerization, one of the initial steps in TLR4 activation. 4-HNE suppressed both ligand-induced and ligand-independent receptor dimerization. The thiol donors, DTT and NAC, prevented the inhibitory effects of 4-HNE on TLR4 dimerization, and LC–MS/MS analysis showed that 4-HNE formed adducts with cysteine residues of synthetic peptides derived from TLR4. These observations suggest that the reactivity of 4-HNE with sulfhydryl moieties is implicated in the inhibition of TLR4 activation. Furthermore, inhibition of TLR4 activation by 4-HNE resulted in down-regulation of the phagocytic activity of macrophages. Collectively, these results demonstrate that 4-HNE blocks TLR4-mediated macrophage activation, gene expression, and phagocytic functions, at least partly by suppressing receptor dimerization. They further suggest that 4-HNE influences innate immune responses at sites of infection and inflammation by inhibiting TLR4 activation.

Ablation of SP-A has a negative impact on the susceptibility of mice to Klebsiella pneumoniae infection after ozone exposure: sex differences

BackgroundSurfactant protein A (SP-A) enhances phagocytosis of bacteria, including Klebsiella pneumoniae, by alveolar macrophages. Ozone, a major air pollutant, can cause oxidation of surfactant and may influence lung immune function. Immune function may also be affected by sex-specific mechanisms. We hypothesized that ablation of SP-A has a negative impact on the susceptibility of mice to Klebsiella pneumoniae infection after ozone exposure, and that sex differences in the effect of ozone do exist.MethodsMale and female SP-A (-/-) mice on the C57BL/6J background were exposed to ozone or to filtered air (FA) used as a control and then infected intratracheally with K. pneumoniae bacteria. Survival rate was monitored during a 14-day period. In addition, protein oxidation levels and in vivo phagocytosis were checked 1 h after inoculation of PBS used as a sham control and after inoculation of K. pneumoniae bacteria in PBS, respectively.ResultsWe found: 1) ozone exposure followed by K. pneumoniae infection decreases survival and alveolar macrophage phagocytic function of SP-A (-/-) mice compared to filtered air exposure (p < 0.05), and females are more affected than males; 2) SP-A (-/-) mice (exposed either to ozone or FA) are more susceptible to infection with K. pneumoniae than wild type (WT) mice regarding their survival rate and macrophage phagocytic function; the phagocytic function of FA SP-A(-/-) is similar to that of ozone exposed WT. 3) ozone exposure appears to increase infiltration of PMNs, total protein, and SP-A oxidation in WT mice; infiltration of PMNs and total protein oxidation appears to be more pronounced in female mice in response to ozone; 4) ozone exposure increases SP-A oxidation in WT females significantly more than in males.ConclusionAbsence (i.e. ablation of SP-A in SP-A (-/-) mice) or reduction of functional activity of SP-A (i.e. oxidation of SP-A in WT mice) increases the susceptibility of mice to experimental pneumonia after ozone exposure, and in both cases females are more affected by ozone exposure than males.

Inhibition of phagocytic function of macrophages in vitro by dimer RNase of Bacillus intermedius

The interactions between rat peritoneal macrophage and Bacillus intermedius dimer RNase cross linked by dimethylsuberimidate was investigated in vitro. It has been found that dimer in the form of RNase at concentrations of 0.5–40μg/ml decreases the phagocytic function of macrophages. This is manifested as an inhibition of phagocytosis and suppression of the fusion of phagosomes with lysosomes in macrophages. Using atomic force microscopy, it is shown that the dimer RNase changes the surface structure of the cytoplasmic membrane more strongly than the monomer. The association between modifications of properties of the membrane and inhibition of the macrophage phagocytic function is discussed.

Azithromycin Improves Macrophage Phagocytic Function and Expression of Mannose Receptor in Chronic Obstructive Pulmonary Disease

Defective efferocytosis (phagocytic clearance of apoptotic cells) in the airway may perpetuate inflammation via secondary necrosis in chronic obstructive pulmonary disease (COPD). We have previously reported that low-dose azithromycin improved alveolar macrophage (AM) phagocytic function in vitro. We investigated collectins (mannose-binding lectin [MBL] and surfactant protein [SP]-D) and mannose receptor (MR) in COPD and their possible role in the azithromycin-mediated improvement in phagocytosis. In vitro effects of azithromycin on AM expression of MR were investigated. MBL, SP-D, and MR were measured in patients with COPD and control subjects. Azithromycin (250 mg orally daily for 5 d then twice weekly for 12 wk) was administered to 11 patients with COPD. Assessments included AM phagocytic ability and expression of MR, MBL, SP-D, bronchial epithelial cell apoptosis, pulmonary function, C-reactive protein, blood/BAL leukocyte counts, cytokine production, and T-cell markers of activation and phenotype. Azithomycin (500 ng/ml) increased MR expression by 50% in vitro. AM MR expression and levels of MBL and SP-D were significantly reduced in patients with COPD compared with control subjects. In patients with COPD, after azithromycin therapy, we observed significantly improved AM phagocytic ability (pre: 9.9%; post: 15.1%), reduced bronchial epithelial cell apoptosis (pre: 30.0%; post: 19.7%), and increased MR and reduced inflammatory markers in the peripheral blood. These findings implicate the MR in the defective phagocytic function of AMs in COPD and as a target for the azithromycin-mediated improvement in phagocytic ability. Our findings indicate a novel approach to supplement existing therapies in COPD.

Stress-Induced Downregulation of Macrophage Phagocytic Function Is Attenuated by Exercise Training in Rats

Background/Aims: Acute restraint stress may induce impaired macrophage phagocytic function. Moderate physical training is associated with beneficial effects on immunological functions. We investigated the effects of moderate physical training on phagocytic function of alveolar macrophages in rats submitted to acute restraint stress. Methods: Thirty male Wistar rats weighing 210–226 g were randomly divided into 4 groups: nontrained rats (n = 7), nontrained rats submitted to stress (n = 8), trained rats (n = 7) and trained rats submitted to stress (n = 8). Trained rats were submitted to a program of moderate running training over a period of 8 weeks. Rats subjected to restraint stress were kept immobilized in glass cylinders (8 cm in diameter and 24 cm long) during 60 min. Phagocytosis capacity of macrophages was evaluated by either Escherichia coli orzymosan stimuli. Results: Restraint stress induced a decrease in phagocytosis of E. coli and zymosan particle stimulation by macrophages. Neither of these alterations was observed in trained animals submitted to acute restraint stress. Conclusions: Our data confirm that acute restraint stress is associated with impaired function of macrophages. Moreover, moderate physical training attenuates the effects of acute stress by a mechanism that involves an increase in tolerance of macrophages.

Norepinephrine suppresses wound macrophage phagocytic efficiency through alpha- and beta-adrenoreceptor dependent pathways

The systemic response to injury is characterized by massive release of norepinephrine (NE) into the circulation as a result of global sympathetic activation. We have recently demonstrated that NE modulates the recruitment of macrophages to the cutaneous wound. We hypothesized that NE suppresses wound macrophage phagocytic function through canonical adrenergic signaling pathways. Murine wound macrophages were harvested at 5 days after injury and treated with physiologic and pharmacologic dose norepinephrine. Phagocytosis of green fluorescent protein-labeled Escherichia coli was assayed by flow cytometry. The signaling pathways mediating NE modulation of wound macrophage phagocytosis were interrogated by pharmacologic manipulation of alpha- and beta-adrenoreceptors (ARs), intracellular cyclic adenosine monophosphate (cAMP), and protein kinase A (PKA). Tissue specificity was determined by comparison of wound macrophages to splenic macrophages. Both physiologic and pharmacologic dose NE suppressed wound macrophage phagocytic efficiency. This effect was mediated by alpha- and beta-ARs in a dose-dependent fashion. Direct stimulation of cAMP-suppressed phagocytic efficiency and blockade of PKA signaling prevented NE-mediated suppression of phagocytic efficiency. Splenic macrophage phagocytic efficiency was less than that of wound macrophages and was not altered by NE. NE has a profound immunosuppressive effect on wound macrophage function that is tissue specific and appears to be mediated through adrenergic receptors and their canonical downstream signaling pathway. Attenuation of post-injury immunosuppression represents another potential mechanism by which beta-AR blockade may reduce morbidity and mortality after severe injury.

Suppression of Phagocytic and Bactericidal Functions of Rat Alveolar Macrophages by the Organic Component of Diesel Exhaust Particles

Exposure to diesel exhaust particles (DEP) was shown to increase the susceptibility of the lung to bacterial infection in rats. In this study, the effects of DEP on alveolar macrophage (AM) phagocytic and bactericidal functions and cytokine secretion by AM and lymphocytes in response to Listeria monocytogenes infection were investigated in vitro and the roles of different DEP components in these processes were compared. Exposure to DEP or the organic extracts of DEP (eDEP) significantly decreased the phagocytosis and killing of L. monocytogenes by AM obtained from normal rats. Washed DEP (wDEP) also decreased AM phagocytosis and bacterial killing to a lesser extent, whereas carbon black (CB) reduced AM phagocytosis but had no significant effect on AM bactericidal activity. DEP or eDEP concentration-dependently suppressed L. monocytogenes-induced secretion of tumor necrosis factor-α, interleukin (IL)-1β, and IL-12 by AM and of IL-2 and interferon-γ by lymphocytes obtained from L. monocytogenes-infected rats, but augmented the AM secretion of IL-10. wDEP or CB, however, exerted little or no effect on these L. monocytogenes-induced cytokines. These results provide direct evidence that DEP, through the actions of organic components, suppresses AM phagocytic and bactericidal functions in vitro. Inhibition of AM phagocytic function and alterations of AM and lymphocyte cytokine secretion by DEP and DEP organic compounds may be implicated in the diminished AM bactericidal activity and the lymphatic arm of the host immune system, thus resulting in an suppressed pulmonary clearance of L. monocytogenes and an increased susceptibility of the lung to bacterial infection.

Novel treatment in peritoneal adhesion prevention: Protection by polypeptides

Objective. To evaluate a novel antiadhesive polypeptide complex containing a combination of poly-L-glutamate and poly-L-lysine in order to study its effectiveness and mechanisms in the prevention of postoperative abdominal adhesions in mice. Material and methods. The length of peritoneal adhesions was measured and expressed in percentage of the wound length in a standardized peritoneal injury model and evaluated 7 days and 4 weeks after adhesion induction. The test compound was administered intraperitoneally following surgery. Peritoneal swabs, including the wound area, were stained in order to determine the peritoneal location and clearance of the polypeptides. Electron microscopy was performed to analyze the wound surface and the ultra-structural changes of the phagocytes in cell culture. Moreover, flow cytometry was used to evaluate the effect on macrophage phagocytic function. Results. The poly-L-lysine and poly-L-glutamate combination significantly decreased peritoneal adhesions both at 7 days’ (p<0.001) and 4 weeks’ (p≤0.001) follow-up. From the first day, the compound was found in the wound, after which this was gradually rebuilt, and covered with mesothelial cells. The macrophages phagocytosed the test compound particles, resulting in significant cell growth, and large phagocytic vacuoles. Conclusions. The intraperitoneal administration of poly-L-lysine and poly-L-glutamate resulted in a significant decrease in experimental postoperative peritoneal adhesions.

Effects of candidate vaginally-applied microbicide compounds on innate immune cells

Ideally, a vaginally-applied microbicide would be effective against a broad range of pathogens but would have minimal effects on the female genital tract. The aim of this study was to determine if representative candidate detergent-type and sulfated/sulfonated polymer-type microbicides altered the composition or function of innate immune cells normally found in the vaginal mucosa. The effect of microbicide on the composition of vaginal leukocytes was tested using a flow cytometric approach. Application of the detergent cholic acid, but not the sulfated polysaccharide lambda carrageenan, resulted in a significant increase in macrophages at the vaginal epithelial surface compared to control treatment (19.3% macrophages compared to 2.8%; p < 0.0004). Phagocytosis of fluorochrome-labeled bacteria by macrophages was inhibited greater than 50% in the presence of 1.0 mg/ml of the sulfonated polymer PRO 2000 but was not inhibited by the same concentration of lambda carrageenan. PRO 2000-pulsed macrophages regained phagocytic function after being washed free of the compound. Culture of macrophages with PRO 2000 also resulted in diminished detection of the surface proteins CD11b and CD18. After treated cells were washed free of PRO 2000, these proteins were detected at levels similar to control treated cells. In conclusion, application of a detergent-type microbicide, but not a sulfated polymer, resulted in the infiltration of inflammatory cells at the vaginal epithelial surface. Phagocytic function of macrophages was lost in the presence of 1 mg/ml PRO 2000 which may have reflected masking of important cell surface proteins by the microbicide; however, there was no evidence of permanent loss of function upon removal of the compound.

Prevention of postoperative peritoneal adhesions: Effects of lysozyme, polylysine and polyglutamate versus hyaluronic acid

Objective. Intraperitoneal adhesions are an important cause of postoperative intestinal obstruction, abdominal discomfort and infertility. In the present study we hypothesized that a combination of polypeptides with different surface properties, resulting in fine disperse low-soluble complexes, could be of benefit in the prevention of abdominal adhesions.Material and methods. Various polypeptides including lysozyme, polyglutamate, polylysine and combinations of all three were evaluated as compared to hyaluronic acid. A standard wound on the parietal peritoneum in mice was used and the evaluated agents were administered immediately postoperatively. The extent of peritoneal adhesions to the injured area was measured and expressed as a percentage of the wound length as evaluated after 7 days. Flow cytometry was performed to evaluate the effect on peritoneal macrophage survival and phagocytic function and the Pick test was used to determine peroxide production in order to estimate toxicity and potential impairment of macrophage function caused by the chemicals.Results. Significant differences were seen among the treatment groups (p<0.001). Both polyglutamate and lysozyme, and polyglutamate together with polylysine significantly decreased adhesion formation as compared to hyaluronic acid. The polylysine–polyglutamate combination was still visible macroscopically on the peritoneal surface after 1 week, though not after 1 month. The polyglutamate–lysozyme mixture was less effective than these individual components alone. The chemicals did not show any toxic effects or altered function in macrophage cell culture.Conclusions. Lysozyme, polyglutamate and, most effectively, a polyglutamate–polylysine combination significantly decreased experimental abdominal adhesion formation. A strong mechanical connection to the wound and prolonged attendance in the surface were noted. Peritoneal phagocyte function did not seem to be influenced by the chemicals.

Influence of dietary vitamin E on phagocytic functions of macrophages in broilers

Vitamin E (VE) is known for its antioxidant properties and has been shown to modulate immune system functions in various species. This study examined the influence of different levels of dietary VE (α-tocopherol acetate) on phagocytic functions of macrophages (abdominal exudate cells) in broiler chickens at 3, 5, and 7 wk. Birds were fed commercial diets containing 16 (control), 110, or 220 mg of VE/kg of feed. Macrophages were elicited into the abdominal cavity by injecting a 3% Sephadex solution prepared in PBS (G50-50, 1 mL/100 g of BW) 42 h prior to harvest. The percentage of phagocytically active macrophages and the number of SRBC phagocytosed per macrophage for unopsonized and antibody-opsonized SRBC were determined. These aspects of macrophage function were assessed based on 900 macrophages per sample. When unopsonized SRBC were used, dietary VE supplementation above control level did not affect phagocytic function of macrophages at wk 3, 5, or 7. With antibody-opsonized SRBC, the percentage of phagocytically active macrophages and the number of SRBC phagocytosed per macrophage were higher (P = 0.08 and P = 0.01, respectively) in 3-wk-old birds fed 110 and 220 mg of VE/kg of feed compared with age-matched controls. This enhancing effect of VE supplementation on macrophage function was not observed in 5- and 7-wk-old broilers. It appears from this study that supplemental VE enhances Fc-receptor-mediated macrophage phagocytic activity at early stages of broiler growth.

Role of macrophages in host resistance to group A streptococci.

Macrophages provide the first line of defense against invading pathogens. The aim of this study was to determine the role of macrophages during infection with group A streptococci (Streptococcus pyogenes) in mice. Here, we report that resident macrophages can efficiently take up and kill S. pyogenes during in vivo infection, as demonstrated by immunofluorescence and electron microscopy, as well as colony counts. To evaluate the contribution of macrophages to the resolution of experimental infection with S. pyogenes, we compared the susceptibility of BALB/c mice rendered macrophage deficient by treatment with carrageenan with that of intact mice. The results show that depletion of macrophages enhanced the susceptibility of BALB/c mice to S. pyogenes infection, as evidenced by 100% mortality of macrophage-depleted mice compared to 90% survival of nondepleted control animals. The in vivo depletion of macrophages strongly enhanced bacterial loads in the blood and systemic organs. Resistance to S. pyogenes can be restored in macrophage-depleted mice by adoptive transfer of purified macrophages. The in vivo blocking of the macrophage phagocytic function by treatment with gadolinium III chloride also resulted in enhanced susceptibility to S. pyogenes. Interestingly, depletion of macrophages prior to or during the first 24 h of infection decreased survival dramatically; in contrast, no mortality was observed in infected nondepleted animals or mice depleted after 48 h of infection. These results emphasize the important contribution of macrophages to the early control of S. pyogenes infection.

A Comparison of the Immune Profile of Commercial Broiler Strains When Raised on Marginal and High Protein Diets

A study was conducted to compare the immunocompetence of four commercial broiler strains (Ross 3F8, Ross x Cobb, Ross 308 and Cobb x Cobb (CC)) that were fed either a marginal protein diet (D1) or a high protein diet (D2) for the starter and finisher diets, respectively. Strain CC showed comparatively higher and more persistent antibody titers against sheep red blood cells (SRBC) (P < 0.0182) as well as higher macrophage phagocytic function for SRBC uptake (P = 0.0118) than the other strains. The Ross 308 strain had significantly greater cell mediated immune response, as measured by T-lymphocyte proliferation response to phytohemagglutinin-P (PHA-P), P < 0.04) and Concanavalin-A (Con-A) (P < 0.0281), as well as for the chemotaxis response to formyl-met-leu-phe (P < 0.0019) than the other strains. The diet effect was variable for monocyte-macrophage functions, but birds on the high protein diets showed higher cell- mediated response than the birds on the low protein diets when measured by Con-A and PHA-P responses. An interaction between strains and diets was seen for antibody response with the Ross 308 showing higher titers on D1 while the CC had greater antibody response when raised on D2. These results suggest that genetic differences exist between various commercial broiler chicken lines for cell mediated, humoral and innate immune responses. Furthermore, dietary protein levels appear to influence the immune response levels of broiler chickens but the response obtained varies by strain. The results of these studies imply that immunocompetence is genetically controlled, and, therefore some measures of immunocompetence could be considered as a selection criterion while selecting for performance traits.