Study on nonspecific immunity in pregnant women: II. Effect of hormones on chemiluminescence response of peripheral blood phagocytes

Sex-dependent dysregulation of human neutrophil responses by bisphenol A

BACKGROUND

In the present study, we aimed to investigate selected functions of human neutrophils exposed to bisphenol A (BPA) under in vitro conditions. As BPA is classified among xenoestrogens, we compared its action and effects with those of 17β-estradiol (E2).

METHODS

Chemotaxis of neutrophils was examined using the Boyden chamber. Their phagocytosis and nicotinamide adenine dinucleotide phosphate hydrogen (NADPH) oxidase activity were assessed via Park's method with latex beads and Park's test with nitroblue tetrazolium. To assess the total concentration of nitric oxide (NO), the Griess reaction was utilized. Flow cytometry was used to assess the expression of cluster of differentiation (CD) antigens. The formation of neutrophil extracellular traps (NETs) was analyzed using a microscope (IN Cell Analyzer 2200 system). Expression of the investigated proteins was determined using Western blot.

RESULTS

The analysis of results obtained for both sexes demonstrated that after exposure to BPA, the chemotactic capacity of neutrophils was reduced. In the presence of BPA, the phagocytic activity was found to be elevated in the cells obtained from women and reduced in the cells from men. Following exposure to BPA, the percentage of neutrophils with CD14 and CD284 (TLR4) expression, as well as the percentage of cells forming NETs, was increased in the cells from both sexes. The stimulatory role of BPA and E2 in the activation of NADPH oxidase was observed only in female cells. On the other hand, no influence of E2 on the expression of CD14 and CD284, chemotaxis, phagocytosis, and the amount of NET-positive neutrophils was found for both sexes. The study further showed that BPA intensified NO production and iNOS expression in the cells of both sexes. In addition, intensified expression of all tested PI3K-Akt pathway proteins was observed in male neutrophils.

CONCLUSIONS

The study demonstrated the influence of BPA on neutrophil functions associated with locomotion and pathogen elimination, which in turn may disturb the immune response of these cells in both women and men. Analysis of the obtained data showed that the effect of this xenoestrogen on the human neutrophils was more pronounced than E2.

Neutrophils life under estrogenic and xenoestrogenic control

Over 100 years ago, scientists had identified cells that represent the most abundant population of peripheral blood leukocytes; they called this population neutrophils. Day by day, the knowledge specific to neutrophils is augmented with new and often surprising aspects and facts about neutrophils' life or death. Estrogens (estrone, estriol, and estradiol) are relevant for the regulation of immune responses that are related with neutrophils. An understanding of the molecular mechanism of the action of endogenous hormones allows us to predict the effects of the substances that commonly occur in an environment with estrogen-like properties (xenoestrogens (e.g., bisphenol A, DDT, tributyltin, polychlorinated biphenyls, nonylphenol and octylphenol)). Therefore, we summarize current literature on the impact of estrogens and xenoestrogens, on each aspect of neutrophil life, as well as describe its mechanism of actions in neutrophils.

Human chorionic gonadotrophin (hCG) enhances immunity against L. tropica by stimulating human macrophage functions

During pregnancy, there are important changes in hormone levels such as the huge production of human chorionic gonadotropin (hCG), which is supposed to influence the immune system. The aim of this study was to investigate the effect of hCG on immune response against Leishmania, through the evaluation of the functions of human macrophages infected with L. tropica. This study demonstrated that hCG significantly increased the NO production by rHu-IFNγ-primed macrophages then infected with L. tropica, which was correlated with decrease in the number of infected macrophages as well as the number of amastigotes per macrophage in a dose-dependent manner; however, the greatest effect was shown with the 250 U/mL concentration. The addition of the same concentration of hCG to rHu-IFNγ-primed macrophages caused also a major increase in both IL-6 and IL-12p40 production. In conclusion, hCG enhances different macrophage functions involved in immunity against L. tropica.

Membrane-bound complement regulatory proteins as biomarkers and potential therapeutic targets for SLE

For the last two decades, there had been remarkable advancement in understanding the role of complement regulatory proteins in autoimmune disorders and importance of complement inhibitors as therapeutics. Systemic lupus erythematosus is a prototype of systemic autoimmune disorders. The disease, though rare, is potentially fatal and afflicts women at their reproductive age. It is a complex disease with multiorgan involvement, and each patient presents with a different set of symptoms. The diagnosis is often difficult and is based on the diagnostic criteria set by the American Rheumatology Association. Presence of antinuclear antibodies and more specifically antidouble-stranded DNA indicates SLE. Since the disease is multifactorial and its phenotypes are highly heterogeneous, there is a need to identify multiple noninvasive biomarkers for SLE. Lack of validated biomarkers for SLE disease activity or response to treatment is a barrier to the efficient management of the disease, drug discovery, as well as development of new therapeutics. Recent studies with gene knockout mice have suggested that membrane-bound complement regulatory proteins (CRPs) may critically determine the sensitivity of host tissues to complement injury in autoimmune and inflammatory disorders. Case-controlled and followup studies carried out in our laboratory suggest an intimate relation between the level of DAF, MCP, CR1, and CD59 transcripts and the disease activity in SLE. Based on comparative evaluation of our data on these four membrane-bound complement regulatory proteins, we envisaged CR1 and MCP transcripts as putative noninvasive disease activity markers and the respective proteins as therapeutic targets for SLE. Following is a brief appraisal on membrane-bound complement regulatory proteins DAF, MCP, CR1, and CD59 as biomarkers and therapeutic targets for SLE.

Cyclosporin-A augments respiratory burst of whole blood phagocytes in pregnant rats

Both pregnancy and cyclosporin A (CsA) are known to inhibit T-cell mediated immune response and to activate phagocytes against microbial infections as a compensatory mechanism. Pregnant women, either with organ transplantation or suffering from autoimmune diseases, are commonly managed with CsA therapy. This investigation was aimed to study effect of CsA on phagocytic activity of whole blood polymorphonuclear leukocytes (PMNs) in pregnant rats. Both pregnant and non-pregnant Sprague-Dawley rats (4 animals per group) were treated with CsA (40 mg/kg, oral) for 7 days starting from gestation day 7. Respective control groups of non-pregnant and pregnant rats received vehicle only. Luminol-dependent chemiluminescence (CL) was used to measure the generation of reactive oxygen species (ROS) in respiratory burst of whole blood PMNs stimulated by zymosan. The results showed a moderate and insignificant increase in CL response in non-pregnant rats with CsA treatment or pregnant rats without CsA treatment. Whereas the CL response of whole blood PMNs was significantly higher (ANOVA F = 35.66, P < 0.001) in pregnant rats treated with CsA. In conclusion, this preliminary study demonstrates synergistic effects of pregnancy and CsA on activation of PMNs resulting in massive and sustained generation of ROS that could be deleterious to both host and fetus.

Monocyte activation, but not granulocyte activation, is inhibited in the presence of developing ovarian follicles

This study was set up to evaluate the influence of ovarian factors on the acute phase of the endotoxin-induced glomerular inflammatory reaction. Six groups of rats with permanent jugular vein cannulas were used. This included three groups with increased progesterone and/or 17beta-oestradiol concentrations (day 14 pregnant rats, pseudopregnant rats and lactating rats), one group with the presence of developing ovarian follicles (cyclic rats), and two groups with both increased sex hormone concentrations and the presence of developing ovarian follicles (day 14 pregnant rats treated with FSH and day 21 pregnant rats). Rats were infused for 1h with either saline or endotoxin (1 microg/kg body weight) and sacrificed 4h after the infusion. Kidney sections were snap-frozen and prepared for immunohistochemistry. Endotoxin-induced glomerular granulocyte infiltration was increased only in the groups of rats with increased progesterone and/or 17beta-oestradiol concentrations. This could be due to endotoxin-induced ICAM-1 and/or VCAM-1 expression, which was observed in all endotoxin-treated groups and in all endotoxin-treated groups with increased sex hormone concentrations, respectively. It could also be due to an effect on granulocytes per se, since the number of endotoxin-induced CD11b-positive cells in the glomeruli was increased only in the groups with increased sex hormone concentrations. Endotoxin-induced glomerular monocyte infiltration, however, was seen only in those groups in which developing ovarian follicles were lacking (i.e. day 14 pregnant, pseudopregnant and lactating rats), suggesting that developing ovarian follicles produce anti-inflammatory factors. These factors did not have an effect on endothelial or leukocyte adhesion molecule expression. We hypothesize that the presence of elevated progesterone concentrations increased the endotoxin-induced glomerular granulocyte infiltration, while endotoxin-induced glomerular monocyte infiltration was inhibited in the presence of developing ovarian follicles.

Gonad development and plasma steroid profiles by HRGC/HRMS during one reproductive cycle in reference and leachate-exposed female perch (Perca fluviatilis)

Endocrine processes were studied in reference female perch (Perca fluviatilis) from Lake Djursjön and in leachate-exposed females from Lake Molnbyggen during one reproductive cycle. A high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) technique enabled the analysis of circulating sex steroids [progesterone (P), 17alpha-hydroxyprogesterone (17alpha-OHP), androstenedione (A), testosterone (T), estrone (E1), and 17beta-estradiol (E2)], the maturation-inducing hormone (MIH) 17alpha,20beta-dihydroxy-4-pregnen-3-one (17alpha,20beta-P), and glucocorticoids [11-deoxycortisol (11-DC) and cortisol]. Body and organ measurements, ratio of sexually mature (SM) females, and frequencies of body lesions, were also recorded. High frequencies of body lesions and a low ratio of SM females were generally found in Molnbyggen. These females also had lower gonadosomatic index (GSI) and liver-somatic index (LSI) in the early stages of vitellogenesis, indicating either a delayed onset of oogenesis or an impaired vitellogenesis. Non-reproducing females from both lakes showed a similar LSI cycle as SM females. Increasing T and A levels in SM females from Djursjön coincided with the GSI peak at the time of spawning. These two androgens were on several occasions lower in SM females from Molnbyggen, possibly the result of a disrupted 17,20-lyase activity of the P450 17alpha enzyme because only minor effects were observed on circulating P and 17alpha-OHP levels. E2 and E1 levels increased during vitellogenesis in females from both lakes, with E1 levels more closely resembling the peaks of A and GSI. Peak levels of 17alpha,20beta-P at the time of spawning confirmed its function as the MIH in perch, while the simultaneous peak of 11-DC suggests that it also may be involved in final maturation of the oocytes.

Sex steroid hormones do not influence the oxidative burst activity of polymorphonuclear leukocytes from ovariectomized cows in vitro

During the periparturient period, dairy cows are subjected to physiological changes that may induce immunosuppression and an increased susceptibility of the animal to bacterial infections such as mastitis. The incidence of clinical environmental mastitis is high during the last period of gestation, at parturition and during the first month of lactation, suggesting a potential influence of sex steroid hormones. Efficient functioning of polymorphonuclear leukocytes (PMN) is necessary during the early phase of infection to clear the mammary gland from invading pathogens. The purpose of this study was to investigate the effect of sex steroid hormones on the oxidative burst activity of isolated PMN from ovariectomized cows. Ovariectomy was performed to minimize the interference of endogenous estrogen and progesterone levels, which are known to vary extensively during the estrus cycle. Isolated PMN were incubated with different concentrations of 17beta-estradiol, estrone or progesterone. A flow cytometric technique was used to quantify the oxidation of intracellular 2',7'-dichlorofluorescin by the oxidative burst system of PMN following stimulation with phorbol myristate acetate. Staurosporine was used as a positive control for our in vitro model. No statistically significant changes in PMN oxidative burst activity were observed at physiological or pharmacological levels of the three sex steroid hormones. A large variation existed in the oxidative burst activity among cows. In an additional experiment, the expression of estrogen receptor alpha and of progesterone receptor in PMN was evaluated immunohistochemically. No specific staining was detected for both receptors in isolated PMN following incubation with different concentrations of sex steroid hormones.

Physiological leukocytosis during pregnancy is associated with changes in glucose transporter expression of maternal peripheral blood granulocytes and monocytes

PROBLEM

The scarce data on glucose transporter expression of leukocytes are contradictory and nothing is known about changes accompanying physiological leukocytosis during pregnancy, which imposes acute metabolic demands on the cells.

METHOD OF STUDY

Cytospin preparations of intravascular leukocytes were searched immunocytochemically for the high affinity glucose transporters GLUT1, 3 and 4. Pregnancy-associated quantitative changes in transporter expression were assessed by flow cytometry.

RESULTS

Granulocytes and monocytes stained for GLUT1, 3 and 4. Major changes in cell surface transporter expression during pregnancy were a 36% (P < 0.05) down-regulation of granulocyte GLUT1 at term, and an increase in monocyte GLUT3 levels to 137% (P < 0.05), paralleled by a 24% (P < 0.05) decrease in GLUT4 content in second trimester. Apart from a minor subpopulation, lymphocytes were negative for these carriers.

CONCLUSION

GLUT1, 3 and 4 are abundantly expressed in granulocytes and monocytes. The particular isoforms are differentially regulated during pregnancy, suggesting an individual functional significance.

Exhalation of H2O2 and thiobarbituric acid reactive substances (TBARs) by healthy subjects

Enhanced exhalation of H2O2 and TBARs have been reported in various inflammatory lung diseases. This may reflect activated phagocytes influx and free radical generation in the airways. However, to apply these compounds as markers of oxidative stress it is necessary to understand factors influencing their exhalation in healthy subjects. We investigated the concentration of H2O2 and TBARs in expired breath condensate (EBC) of 58 healthy volunteers. EBC was collected seven times every 4 h during 24 h and three times every 7 d during 2 consecutive weeks. The H2O2 exhalation revealed diurnal variation with two-peak values 0.45 +/- 0.29 microM and 0.43 +/- 0.22 microM at 12:00 and 24:00 h. The lowest concentrations, 0.26 +/- 0.13 microM and 0.25 +/- 0.26 microM, were found at 20:00 and 8:00 h. Cigarette smokers exhaled about 2.4 times more H(2)O(2) than never smoked subjects. Moreover, in contrast to nonsmokers, cigarette smokers' H2O2 exhalation was stable over 2 week observation. The mean H2O2 concentration estimated over the whole 2 week period was higher in subjects above 40 years regardless of smoking habit, and it positively correlated with age in never smoked subjects (p <.004). Smoking of one cigarette caused 1.8-fold rise in H2O2 exhalation (p <.01). The baseline H2O2 levels correlated with cumulative cigarette consumption (p <.05) and MEF 25% of predicted (p <.05). Neither moderate exercise nor one puff of salbutamol nor ipratropium influenced significantly the concentration of H2O2 and TBARs in EBC. Only 4 of 120 EBC specimens from never smoked subjects revealed detectable levels of TBARs. Cigarette smokers exhaled more TBARs (p <.05) than never smoked volunteers. Our results indicate that healthy never smoked subjects exhale H2O2 with diurnal variation and significant changes over 2 week observation. Cigarette smoking enhanced H2O2 generation in the airways. These results could be useful for planning studies with exhaled H2O2 as a marker of airway inflammation. Occasional detection of TBARs in EBC of never smoked persons may be a result of sufficient antioxidant activity in the airways that protects tissues from peroxidative damage.

Differences in innate immunologic response to group B streptococcus between colonized and noncolonized women

OBJECTIVE

To evaluate the functional capacity of granulocytes and monocytes from pregnant and nonpregnant women in relation to group B streptococcus (GBS) colonization status.

METHODS

Engulfment of fluorescent GBS by peripheral blood phagocytes from GBS-colonized and noncolonized women was measured by flow cytometry. Intracellular superoxiode generated in response to GBS challenge to monocytes and granulocytes enriched from peripheral blood of these women was also measured by flow cytometry, and extracellular superoxide was determined by colorimetric assay.

RESULTS

Monocytes and granulocytes from pregnant, GBS-colonized women engulfed significantly greater numbers of GBS than phagocytes from pregnant, noncolonized women. No difference in intracellular superoxide production was detected between any of the groups of women; however, monocytes from pregnant, colonized women released significantly more superoxide into the extracellular milieu than did granulocytes from the same women. No differences in extracellular release of superoxide were observed among noncolonized women whether they were pregnant or not.

CONCLUSIONS

Monocytes from pregnant, colonized women engulf more GBS and release more of the superoxide into the extracellular environment, where it is unlikely to be an effective defense mechanism against intracellular bacteria. This suggests that components of the innate immune system that should serve in a protective role may function suboptimally, thereby contributing to the colonization process by GBS.

Nonspecific immunity in pregnancy: monocyte surface Fcgamma receptor expression and function

The state of pregnancy is an immunological enigma during which the body must prevent rejection of the antigenically foreign fetus while at the same time maintain sufficient maternal host defense mechanisms to combat infection. Although most studies on the immunology of pregnancy focus on immune suppression, several studies have shown an increase in nonspecific host defense, which is postulated to be a compensatory mechanism for decreased specific immunity during pregnancy. Studies in this laboratory have shown that monocyte surface FcgammaRI (CD64) and FcgammaRII (CD32) expression progressively increase throughout pregnancy, while surface MHC class II expression remains unchanged. Functional studies revealed that the number of phagocytic monocytes which could be isolated from pregnant women was increased. These cells exhibited an increased capacity to ingest IgG-opsonized human erythrocytes. This study shows for the first time that monocyte surface FcgammaR expression and FcgammaR-mediated functions are increased during pregnancy. These results support the hypothesis that nonspecific immunity as represented by FcgammaR expression and function is increased during pregnancy.

Phagocytic and metabolic activities of macrophages from mummichog naturally exposed to pulp mill effluents in the Miramichi River

Chemicals present in bleached kraft pulp mill effluents (BKMES) can modulate the immune response of fish. This work was conducted to determine if mummichogs living downstream from a bleached kraft pulp mill (BKM) had an impaired immune response. Head kidney phagocytes from males and females were tested for their phagocytic and metabolic activities. Mummichogs were captured 4 km (S2) and 39 km (S1) downstream from a BKM in the Miramichi estuary (New Brunswick, Canada) and at two sites located upstream (S3) and 20 km downstream (S4) in a reference estuary, the Bouctouche. Both male and female mummichogs captured at S2 in the Miramichi estuary had a lower phagocytic activity, whereas only females from the same site had a decreased oxidative burst response, indicating a difference between sexes in the susceptibility to pollutants present in the Miramichi. Therefore, the results indicate that mummichogs exposed to BKMES have an impaired immune response and that females are more sensitive than males to the chemicals present in BKMES.

Immune function in healthy adolescents

In the present study, we examine immunological functioning in normal healthy African-American and Latino/Latina adolescents recruited from an inner-city high school and an inner-city clinic. A battery of tests was performed with enumerative and functional measures which encompassed both innate and adaptive immunity. We found immune differences related to age, gender, and race on both the enumerative and the functional immune measures. This data expands the available body of information concerning normal immunity in healthy adolescents.

Differential secretion of chemokines from peripheral blood in pregnant compared with non-pregnant women

The maintenance of a normal pregnancy is dependent on the delicate interaction between the endocrine and the immune systems. Cytokines are thought to play a key role in pregnancy by way of local modulation of the immune system at the level of peripheral leukocytes. This study examined the potential of peripheral venous blood cultures from pregnant women throughout gestation and from non-pregnant women to produce the chemokines monocyte chemotactic protein-1 (MCP-1), interleukin-8 (IL-8) and RANTES. Significantly (P = < 0.001), higher levels of MCP-1 were released from peripheral blood cultures from pregnant women at term than during the first trimester or from women who were not pregnant. This could not be accounted for by differences in differential blood counts. Significantly higher levels (P = < 0.05) of MCP-1 were released from PBMC preparations from pregnant compared with non-pregnant women. No 'rebound' increase in MCP-1 was observed on withdrawing progesterone support to the PBMC preparations. MCP-1 was secreted predominately from CD14+ cells with those from pregnant women producing more than those from non-pregnant women. There was no statistical difference in release of IL-8 or RANTES from either peripheral blood or PBMC preparations from pregnant or non-pregnant women. IL-8 and RANTES were secreted from CD14+ and CD14- cells, respectively. The hypothesis proposed is that the monocytes are fundamentally different in pregnancy and that measurement of MCP-1 has the potential to act as a marker of pregnancy status.

Steroid sex hormones and macrophage function: regulation of chemiluminescence and phagocytosis

PROBLEM

Female sex hormones modulate a variety of humoral and cell-mediated immunologic functions. In this study, the effects of estrogen, progesterone, and testosterone on the chemiluminescence (CL) response and phagocytic ability of male rat peritoneal macrophages (M luminal diameter) were examined.

METHOD

In M luminal diameter pretreated with 10(-2) ng/ml of 17 beta-estradiol (E2) for 20 hours, the CL generated in response to phorbol myristate acetate (PMA), 1,2-dioctanoyl-rac-glycerol (C8:0), or opsonized zymosan (OZ) was significantly increased by 135%, 140%, and 136% of control values, respectively. In addition, M luminal diameter treated with 10(-5) ng/ml or 10 ng/ml of E2 exhibited a significantly greater PMA- or OZ-stimulated CL response than did untreated controls.

RESULTS

At 10(-2) ng/ml, progesterone enhanced and testosterone reduced the CL response, but these changes were not statistically significant. In time course studies, the PMA-stimulated CL response of M luminal diameter treated with 10(-2) ng/ml of E2 or progesterone for 5 h was significantly less than that of the untreated group. In the presence of endotoxin (12 pg/ml), the CL response in M luminal diameter treated with E2 or testosterone was significantly depressed as compared to untreated controls. Phagocytosis of opsonized sheep erythrocytes also was significantly enhanced (140% to 190% of control) when M luminal diameter were pretreated with 10(-12) M to 10(-8) M of either E2 or progesterone.

CONCLUSIONS

These findings suggest that, at physiological concentrations, E2 is capable of modulating both CL generation and phagocytic uptake by M luminal diameter in a manner not shared by other steroid hormones.

Increased phagocytic activity of polymorphonuclear leukocytes during pregnancy

Many immunological parameters are depressed during pregnancy. For this reason, an evaluation was made of the phagocytic activity, representing non-specific immunity, of polymorphonuclear leukocytes from pregnant women. The cells were isolated from heparinized venous human blood of pregnant women of 10 or more weeks' gestation and non-pregnant women (controls), 20-30 years old. The results indicate that the phagocytosis of inert particles (latex beads) does not significantly change in pregnancy. However, the attachment, ingestion and digestion of Candida albicans significantly increased in pregnancy, with the greatest difference from controls being in the second trimester. These findings suggest that the phagocytic activity in pregnant women is enhanced and that this increased non-specific immunity may compensate in part for weakened specific immunity of the maternal host.