Capacity Of Peritoneal Macrophages Research Articles

Role of MP-4 myelopeptide in regulation of antibody production and functional activity of macrophages under stress conditions

Myelopeptides are endogenous low-molecular weight peptides with immunoregulatory activity. Each of these myelopeptides has an individual sequence and plays a role in correction of immune system disorders. In our earlier studies, we have shown immunomodulatory effect of MP-3, MP-5, MP-6 myelopeptides upon functioning of peritoneal macrophages under the conditions of immobilization and cold stresses. The aim of this work was to investigate the effect of MP-4 myelopeptide upon antibody formation, production of reactive oxygen species, and absorptive activity of peritoneal macrophages in mice under the immobilization stress. Materials and methods. The in vivo experiments were carried out in 24 male Swiss mice weighing 17-22 g. Two-or six-hour immobilization stress was produced in the animals. MP-4 was injected intraperitoneally 30 min before the onset of stress, at a dose of 40 μg/kg. The animals were divided into 4 groups: 1, control; 2, stress; 3, stress + MP-4; 4, MP-4 injection. On day +5, cellularity and the number of antibody-forming cells (AOC) in spleen were assessed by the method of local hemolysis in an agarose gel according to Jerne. Production of reactive oxygen species by peritoneal cells was assessed using the luminol-dependent chemiluminescence (LZHL) reaction. The absorption capacity of peritoneal macrophages was assessed using a standard method using a BDFACSCalibur laser flow cytometer. Labeled St. aureus at a final concentration of 108 cells/ml were used as phagocytosis targets. Statistical analysis was performed using the unpaired Student's t-test. Results. It was found that two-hour immobilization stress did not affect the absorption activity of peritoneal leukocytes, whereas six-hour stress suppressed phagocytosis. Injection of MP-4 in stress-exposed animals did not lead to changes in phagocytic activity of peritoneal macrophages. MP-4 did not correct the stress-induced decrease in the number of antibody-forming cells from the spleen during six hours of immobilization, nor stress-induced increase in absolute amounts of AOC under the two-hour immobilization stress. In the group of animals receiving MP-4 and immobilized for two-hours, an increase in the number of nucleated cells was increased, as compared with the control group. Thus, in contrast to the previously studied myelopeptides, MP-4 did not show pronounced immunomodulatory effects upon these parameters.

Supplementation of Black Soldier Fly (Hermetia illucens) on Activity and Capacity Phagocytic Macrophage of Laying Hens

Black Soldier Fly are natural antibiotics. It is expected that the use of BSF larvae in poultry rations as an alternative source of conventional protein will contribute to improving the immune status and maintaining animal health, thereby reducing the use of antibiotic growth promoters (AGPs). This study aimed to evaluate the effect of the best type of BSF protein for determining the health status of laying hens based on the activity and capacity of macrophage phagocytosis on the non-protein A bacterium Staphyllococcus aureus. Results of this study indicated that the BSF extract (P3) has the highest phagocytic capacity value. This result proves that the BSF extract can induce macrophage cells to optimally process bacterial cells or foreign phagocyte particles. The highest average activity value, and phagocytic capacity of peritoneal macrophages was resulted from BSF extract (P3), respectively was 91.34 ± 0.38% and 22.84 macrophage-1 bacteria.

Sulfated Radix Cyathulae officinalis Polysaccharides Act as Adjuvant via Promoting the Dendritic Cell Maturation and Suppressing Treg Frequency

This study was conducted to evaluate the adjuvant potential of sulfated Radix Cyathulae officinalis Kuan polysaccharides (sRCPS) and their effects on specific cellular and humoral immune responses to hepatitis B subunit vaccine in mice. Our data demonstrated that sRCPS significantly promoted the rHBsAg-specific IgG, IgG1, IgG2a, and IgG2b antibody titers, the activities of natural killer cells (NK) and cytotoxic T lymphocytes (CTL), T cells proliferation, and phagocytic capacity of peritoneal macrophages. Furthermore, sRCPS increased the levels of IL-4, IL-2, and IFN-γ in CD4+T cells and the level of IFN-γ in CD8+T cells. In addition, sRCPS enhanced the expression of CD40+, CD80+, CD86+, MHC I and MHC II in dendritic cells (DCs) and upregulated the mRNA levels of MHC I, MHC II. sRCPS downregulated the frequency of CD4+CD25+Foxp3+ Treg cells. sRCPS increased both cellular and humoral immune responses by upregulating DC maturation, and suppressing the frequency of Treg cells.

The synthetic peptide octraphin TPLVTLFK is a selective agonist of nonopioid β-endorphin receptor

The peptide TPLVTLFK (coined by the authors “octarphin”), corresponding to the amino acid sequence of β-endorphin fragment 12–19, and its analogs (LPLVTLFK, TLLVTLFK, TPLVLLFK, TPLVTLLK, TPLVTLFL) were synthesized. The peptide octarphin was labeled with tritium (specific activity, 28 Ci/mol) and its binding to the rat brain cortex membranes and mouse peritoneal macrophages was studied. [3H]Octarphin was found to bind to brain membranes and macrophages with high affinity (Kd = 2.6 ±0.2 and 2.3 +0.2 nM, respectively) and specificity. The specific binding of [3H]octarphin with rat brain membranes and mouse macrophages was inhibited by unlabeled β-endorphin (Ki = 2.4 +0.2 and 2.7 +0.2 nM, respectively) and selective agonist of nonopioid β-endorphin receptor synthetic peptide immunorphin (SLTCLVKGFY) (Ki = 2.9 +0.2 and 2.4 +0.2 nM, respectively) and was not inhibited by unlabeled naloxone, α-endorphin, γ-endorphin and [Met5]enkephalin (Ki > 10 mM). Inhibiting activity of unlabeled analogs of octarphin was more than 100 times lower than that of the unlabeled octarphin. Octarphin was shown to stimulate activity of mouse immunocompetent cells in vitro: at the concentration of 1 nM it enhanced the capacity of peritoneal macrophages to digest bacteria Salmonella typhimurium virulent strain 415 in vitro. Thus, octarphin is a selective agonist of nonopioid (insensitive to the opioid antagonist naloxone) β-endorphin receptor of rat brain cortex membranes and mouse peritoneal macrophages.

Antigen-presenting capacity of macrophages and dendritic cells in the peritoneal cavity of patients treated with peritoneal dialysis.

In this study the antigen-presenting capacity of human peritoneal cells and the influence of continuous ambulant peritoneal dialysis (CAPD) were studied. On average 6% of the peritoneal cells were dendritic cells (DC), with no difference between CAPD and control peritoneal cells. DC were enriched by selecting for non-adherent, Fc receptor-negative, low density cells. A typical spot-like CD68 positivity was seen in DC, in contrast to the pancytoplasmic staining pattern in macrophages. Peritoneal DC morphologically and functionally showed features of cells belonging to the DC lineage. Peritoneal DC were superior antigen-presenting cells for both allo-antigen, and Candida albicans antigen or purified protein derivative. CAPD peritoneal macrophages were two- to three-fold better stimulator cells for allogeneic T cells compared with control macrophages. The level of integrins/adhesins or MHC class I or II, as measured semi-quantitatively on the FACS, could not account for this phenomenon. In addition, a double chamber system showed that dialysate-activated macrophages produced soluble factors that could enhance DC-induced allogeneic T cell proliferation. In conclusion, human peritoneal cells contain a relatively high percentage of classical DC. CAPD treatment does not impair the antigen-presenting capacity of peritoneal cells, but instead upregulates the allo-antigen-presenting capacity of peritoneal macrophages.

Functional competence of peritoneal macrophages in murine Lyme borreliosis

In mice infected with the Lyme disease spirochete, Borrelia burgdorferi, spirochetes can be cultured from the uninflamed peritoneal cavity despite their proximity to resident macrophages. Here we have evaluated the phagocytic and killing capacity of peritoneal macrophages ex vivo from such mice, and compared them to cells from uninfected controls. We noted no significant differences in the numbers of cells recovered from lavage fluid nor in the proportion of lymphocytes in that fluid or their type or state of activation; B cells vs. T cells, CD4 vs. CD8, T cell receptor display (TCRαβ vs. TCRγδ), or B cell activation markers (CD24 vs. CD44). In addition, in studies conducted with coded samples, macrophages from infected animals were similar to controls in their ability (i) to bind and ingest spirochetes as shown by immunofluorescent kinetic studies imaged by confocal microscopy, (ii) to kill spirochetes as detected by acridine orange vital staining in live confocal microscopy, and (iii) to generate H2O2, a measure of their activation. Finally, we observed no difference in the ability of cells isolated from infected mice to kill the parasite, Toxoplasma gondii, a sensitive functional measure of the activation of killing capacity. Thus, despite the failure of immune clearance that results in persistent or chronic disease in vivo, there does not appear to be a global impairment of macrophage function in the infected host. It remains to be determined whether specific sites of inflammation, e.g., skin, joints, heart, are associated with a downregulation of phagocyte function locally.

Intracellular acidification mediates the inhibitory effect of peritoneal dialysate on peritoneal macrophages.

Commercial peritoneal dialysis solution (CDS) is known to have a detrimental effect on the capacity of peritoneal macrophages (PM phi) to kill bacteria and produce acute phase cytokines. This cytotoxic effect is largely caused by the low pH of CDS. Because the cytoplasmic pH (pHi) is an important determinant of cellular function, the effect of CDS on the pHi of PM phi from continuous ambulatory peritoneal dialysis patients was studied. The pHi of PM phi was measured fluorometrically in N-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES)-buffered salt solution (HBSS) or CDS at pH values of 5.3, 6.5, and 7.0, values that represent the pH existing in dialysate during the first 30 min of dwell time. For any given pH of the experimental medium, the pHi was always more acidic in CDS than in HBSS. When PM phi were incubated with a lactate-containing HBSS, a cellular acidification was observed that was similar to that attained by exposure to CDS at the same pH. This supports the hypothesis that the decrease in pHi was due to the influx of lactic acid from the CDS into the PM phi. In order to demonstrate a causal association between the CDS-induced cellular acidification and a defect in phagocytosis and cytokine production, these functions were studied after pHi clamping by means of K+/nigericin. It was found that clamping pHi to values below 6.5 led to a markedly reduced tumor necrosis factor-alpha production and phagocytosis. However, at values of pHi > 6.5, these functions were normal. (ABSTRACT TRUNCATED AT 250 WORDS)

Orally Administered Phospholipids Inhibit Abdominal Rubber-Drain-Induced Bacterial Translocation in the Rat

In order to determine the influence of phospholipid on abdominal biomaterial-induced bacterial translocation (BT), phsophatidylcholine (PC) or phosphatidylinositol (PI) was administered orally or intraperitoneally in rats with intraperitoneal implantation of 7-cm2 rubber drain pieces. Two days after surgery, the incidence of translocation to mesenteric lymph nodes and liver significantly decreased, the adherence of 3H-labeled Escherichia coli to the ileal mucosa was significantly inhibited and the phagocytic and bactericidal capacity of peritoneal macrophages increased in animals with PC or PI administered orally, but not intraperitoneally, as compared with rats without phospholipid administration. Scanning electron microscopy revealed a coating layer on the surface of the intestinal mucosa in phospholipid-gavaged rats. Thus, the results in the present study imply that oral, but not intraperitoneal, PC of PI administration reduces enteric BT induced by intraperitoneal drain implantation.

Effect of leukocyte and other tissue dialysates on NBT reduction and prostaglandin production in mice.

The effects of human leukocyte, porcine spleen and bovine liver dialysate fractions on Listeria resistance were measured by survival studies and by assessing the capacity of peritoneal macrophages to produce superoxide anion (0-2) and prostaglandins. Leukocyte (DLE) and other tissue dialysates were fractionated on a Sephadex G-10 column. Thereafter the significant activities were found in fraction III of DLE, fraction II of porcine spleen and fraction II + III of bovine liver dialysate. The treatment with active porcine spleen dialysate fraction increased the capacity of peritoneal macrophages to generate superoxide anion. On the other hand, this fraction significantly decreased the production of prostaglandin PGE2 and thromboxan B2. These results may indicate that all dialysates can be a source of a non-specifically-acting immunomodulatory preparation and that the infection-resistance-increasing substances seem to operate via the monocyte/macrophage activation.

Effects of chronic ethanol ingestion on arachidonic acid metabolism in rat tissues and in vitro effect of ethanol on camp in platelets

Effects of chronic ethanol ingestion (3 weeks) on the capacity of peritoneal macrophages, lung and heart tissues, to metabolize endogenous arachidonic acid (AA) in rats, and the in vitro effect of ethanol on 3′–5′ cyclic adenosine monophosphate (CAMP) levels in rat platelets were studied. Peritoneal resident macrophages were stimulated by calcium ionophore (A23187) and levels of 5-hydroxyeicosatetraenoic acid (5-HETE), leukotriene B 4 (LTB 4) and PGE 2 were measured by radioimunoassay. There were no differences in levels of the eicosanoids synthesized by macrophages between the ethanol treated and the control group. There were also no differences found in levels of the eicosanoids synthesized by heart or lung homogenate between the two groups. These results suggest that chronic ethanol ingestion does not alter the capacity to synthesize the eicosanoide from the endogenous precursor in tissues studied here. Preincubation of ethanol with platelet rich plasma resulted in a dose dependent increase in cAMP levels. The well documented inhibitory effects of ethanol in vitro on aggregation and AA metabolism in platelets may be due to the enhanced cAMP levels.

Fc- and complement receptor-dependent degradation of soluble immune complexes and stable immunoglobulin aggregates by guinea pig monocytes, peritoneal macrophages, and Kupffer cells.

The degradation of soluble immune complexes (ICx) and stable soluble immunoglobulin aggregates was studied in vitro. To obtain insight into the capacity of phagocytes from different organs to degrade soluble ICx we studied monocytes, peritoneal macrophages, and Kupffer cells. Peritoneal macrophages and Kupffer cells degrade similar amounts of aggregated guinea pig IgG2 (AIgG) and ICx per cell. Monocytes were at least ten times less effective than peritoneal macrophages and Kupffer cells. The presence of normal guinea pig serum as a source of complement enhanced the degradation of ICx and AIgG by peritoneal macrophages and monocytes. There was, however, a diminished degradation of ICx and AIgG by freshly isolated Kupffer cells in the presence of complement. After culturing of the Kupffer cells for 40 hours, there was an increase in the density of C3b receptors and a concomitant reversal of inhibition of AIgG degradation in the presence of complement. It can be concluded from the present experiments that the capacities of peritoneal macrophages and Kupffer cells to degrade soluble ICx and AIgG are comparable and that monocytes are much less active than peritoneal macrophages and Kupffer cells.

Immunomodulation in guinea pigs by porcine spleen cell dialysate.

The effect of porcine spleen dialysate was studied on delayed-type hypersensitivity reactions, as well as on the phagocytic capacity and intracellular prostaglandin levels of peritoneal macrophages. Porcine spleen cell dialysate was fractionated on Sephadex G-10 and these fractions, as well as unfractionated dialysate, were injected intraperitoneally into antigen-primed guinea pigs. The guinea pigs were tested for delayed-type hypersensitivity towards PPD and SK-SD. The results show that unfractionated spleen cell dialysate augmented slightly the delayed-type hypersensitivity reactions, and after fractionation a significant augmentory activity was detected in two adjacent, early eluting fractions. This active elution region corresponds to the elution region where most of the guinea pig DTH augmenting activity of leukocyte dialysate is also detected. Furthermore, these fractions significantly augmented the phagocytic capacity of peritoneal macrophages, and decreased the intracellular levels of prostaglandin PGE2, thromboxan B2 and prostacyclin. These results indicate that porcine spleen cells from non-immunized animals can be used as a source for a non-specifically acting immunomodulatory preparation, which resembles that found in human leukocyte dialysate. These immunomodulatory substance(s) seem to operate via monocyte activation.