Molecular Human Reproduction, Vol. 7, No. 3, 265-270,
March 2001
© 2001 European Society of Human Reproduction and Embryology
Uterine physiology |
Effects of interleukin-4 on the in-vitro production of cytokines by human endometrial stromal cells
Department of Obstetrics and Gynecology, Oita Medical University, Hasama-machi, Oita 879-5593, Japan
Abstract
A T helper (Th)1/Th2 model has been applied to as a system regulating the cytokine network during pregnancy. To evaluate the effects of interleukin (IL)-4, a Th2 cytokine, on the cytokine production by endometrial stromal cells (ESC), an enzyme-linked immunosorbent assay was used to measure the concentrations of IL-6, IL-8, monocyte chemoattractant protein-1 (MCP-1), and macrophage colony-stimulating factor (M-CSF) in the culture media of ESC and of an endometrial stromal sarcoma cell line, MaMi, following the addition of recombinant human IL-4. The expression of mRNAs for IL-6 and IL-8 in ESC after stimulation with IL-4 was also evaluated by Northern blot analysis. Increases in the concentrations of IL-6, IL-8, MCP-1, and M-CSF in the culture media of ESC and MaMi cells were observed on the addition of increasing amounts of IL-4. This cytokine also stimulated the transcription of IL-6 and IL-8 in ESC in a dose-dependent manner. It is suggested that IL-4 secreted by the maternal decidual tissue as well as by the developing embryo may stimulate the production of IL-6, IL-8, MCP-1, and M-CSF by ESC. The increased concentration of these cytokines in the local environment may contribute to the maintenance of early pregnancy by modulating the immune reaction at the feto–maternal interface.
cytokines/endometrial stromal cell/interleukin-4/interleukin-6/interleukin-8
Introduction
Human endometrial stromal cells (ESC) produce and secrete a variety of cytokines, including interleukin (IL)-6 (Nasu et al., 1998a
,b), IL-8 (Arici et al., 1993; Nasu et al., 1998a,b), macrophage colony-stimulating factor (M-CSF) (Hatayama et al., 1994; Nasu et al., 1998b) and macrophage chemoattractant protein-1 (MCP-1) (Arici et al., 1995; Nasu et al., 1998a,b). Human trophoblast in the feto–maternal interface has been shown to produce such cytokines as IL-1 (Haynes et al., 1993), IL-2 (Boehm et al., 1989), IL-4 (Haynes et al., 1993; Jones et al., 1995; De Moraes-Pinto et al., 1997), tumour necrosis factor (TNF)-
(Haynes et al., 1993) and interferon-
(IFN-) (Haynes et al., 1993). The expression of these cytokines and growth factors is thought to be important in implantation and in the maintenance of early pregnancy (Tabibzadeh, 1994; Chard, 1995).
The response of T helper (Th) cells upon activation is characterized functionally according to the cytokines produced, and these are roughly divided into two subsets: type 1 cells (Th1) and type 2 cells (Th2) (Mosmann et al., 1986; Mosmann and Sad, 1996). Normal pregnancy has been suggested to resemble a Th2-dominant situation, which is characterized by a lack of strong maternal cell-mediated anti-fetal immunity with the humoral immune response being dominant (Wegmann et al., 1993; Raghupathy, 1997). A Th2 bias in normal pregnancy has been demonstrated by showing that mouse feto–placental tissues spontaneously secrete the Th2-type cytokines IL-4, IL-5 and IL-10 (Wegmann et al., 1993). The number of IL-4and IL-10-secreting peripheral blood mononuclear cells is significantly increased during normal pregnancy (Marzi et al., 1996; Matthiesen et al., 1998). Recently, the production of leukaemia inhibitory factor (LIF), IL-4 and IL-10 by decidual T cells of women with unexplained recurrent abortions was found to be decreased in comparison with that of women with normal gestation (Piccinni et al., 1998).
IL-4, which belongs to a Th2 cytokine family, is a pleiotropic cytokine with multiple immune response-modulating functions. In the human placenta obtained in the first trimester, IL-4 mRNA and protein are localized to the syncytiotrophoblasts, cytotrophoblasts and the mesenchymal cells in the villus core (Haynes et al., 1993; De Moraes-Pinto et al., 1997). Decidual macrophages and vascular endothelial cells also express IL-4 (De Moraes-Pinto et al., 1997). We have previously reported that IFN-, a Th1-type cytokine, up-regulates the production of IL-6, MCP-1 and M-CSF by ESC (Nasu et al., 1998b), whereas the production of IL-8 by ESC was inhibited by IFN-. The present study investigated whether IL-4 would regulate the production of IL-6, IL-8, MCP-1 and M-CSF by normal ESC as well as an endometrial stromal sarcoma-derived cell line, MaMi (Nasu et al., 1998a,b). We also consider the role of IL-4 in the cytokine network at the feto–maternal interface during early pregnancy.
Materials and methods
Cell culture conditions
Normal specimens of endometrium were obtained with informed consent from seven premenopausal Japanese women who had undergone a hysterectomy for an intramural leiomyoma. All specimens were verified to be from the late proliferative stage (days 11–13 of the menstrual cycle) based on standard histological criteria. Normal ESC were separated from the epithelial glands by digesting the tissue fragments with collagenase as previously described (Arici et al., 1993; Nasu et al., 1998a,b). Briefly, endometrial tissue was cut into 2–3 mm pieces and incubated with collagenase (200 IU/ml) (Gibco-BRL, Gaithersburg, MD, USA) in Roswell Park Memorial Institute (RPMI) 1640 medium (Gibco-BRL) with stirring for 2 h at 37°C. The suspension was then filtered through a 150 µm wire sieve to remove mucus and undigested tissue. The filtrate was passed through a 80 µm wire sieve, which allowed the passage of stromal cells, while retaining the intact glands. After being washed three times with serum-free RPMI 1640, the cells (106 cells/ml) were transferred to culture flasks (Corning, New York, NY, USA) that contained RPMI 1640 supplemented with 10% heat-inactivated fetal bovine serum (FBS; Gibco-BRL), streptomycin (100 IU/ml) (Gibco BRL), and penicillin (100 IU/ml) (Gibco-BRL). The culture medium was replaced every 4 days. These experiments used cells that were obtained after three passages (15–20 days after isolation) using standard methods of trypsinization. These cells were >98% pure, as confirmed by immunocytochemical staining with antibodies to vimentin (V9; Dako, Glostrup, Denmark), keratin (Dako), factor VIII (Dako) and leukocyte common antigen (2B11+PD7/26, Dako). These cells also maintained the ability to decidualize when induced by medroxyprogesterone acetate.
The endometrial stromal sarcoma cell line, MaMi, that constitutively produces IL-6, IL-8, MCP-1 and M-CSF, was previously established (Nasu et al., 1998a,b). MaMi cells were maintained under the conditions described above. Cultures were incubated at 37°C in an atmosphere of 5% CO2 in air at 100% humidity.
Detection of IL-6, IL-8, MCP-1, and M-CSF by enzyme-linked immunosorbent assay (ELISA)
To study the production of IL-6, IL-8, MCP-1 and M-CSF by ESC and MaMi cells, 1x106 cells were plated on 6-well culture plates (Corning) in 1 ml of culture medium with 10% heat-inactivated FBS and cultured until fully confluent. The supernatant was replaced with fresh culture medium that contained various amounts of recombinant human IL-4 (0.0001–100 ng/ml) (R&D Systems, Minneapolis, MN, USA). Under these conditions, the supernatant was collected 24 h after stimulation and stored at –70°C until assayed. Cells that were isolated from one patient were used for each experiment at a time. For confirmation, four experiments were performed and each experiment was performed in triplicate. All experiments were done in the presence of 10% heat-inactivated FBS.
The concentrations of IL-6, IL-8, MCP-1 and M-CSF in the supernatants were determined with commercially available ELISAs (R&D systems). The sensitivity of each assay was as follows: 0.70 pg/ml for IL-6, 4.4 pg/ml for IL-8, 5.0 pg/ml for MCP-1, 8.0 pg/ml for M-CSF. The number of cultured cells was quantified by the Methylene Blue method (Nasu et al., 1995) to evaluate the effect of IL-4 on the cell growth. Briefly, after collecting the supernatant and washing once with phosphate-buffered saline (PBS), the cells were fixed with 3% paraformaldehyde. The cells were then rinsed with 0.1 mol/l borate buffer (pH 8.5), followed by staining with 1% Methylene Blue. After washing four times with 0.1 mol/l borate buffer, the stained cells were lysed with 1 N HCl, and subjected to photocytometry analysis at an absorbance at 595 nm.
Northern blot analysis for IL-6 and IL-8 mRNA
To study the expression of IL-6 and IL-8 mRNA in ESC, 1x106 cells were plated on 75 cm2 culture flasks (Corning) in 15 ml of culture medium with 10% FBS and cultured until fully confluent. The supernatant was replaced with fresh culture medium that contained various amounts of IL-4 (0.001–10 ng/ml), and the cells were further cultured for 4 h. Total RNA was extracted as previously described (Nasu et al., 1999a,b). Briefly, the cells were disrupted with 2 ml of Isogen solution (Nippon Gene, Tokyo, Japan), stored at room temperature for 5 min, and shaken vigorously for 15 s after the addition of 0.2 ml of chloroform. The homogenates were centrifuged at 12 000 g at 4°C for 15 min, followed by the addition of 0.5 ml of isopropanol to the aqueous phase. Each aliquot was stored at room temperature for 10 min and centrifuged at 12 000 g at 4°C for 10 min. A volume of 75% ethanol (Wako, Osaka, Japan) was added to the precipitate. The aliquot was shaken vigorously and centrifuged at 12 000 g at 4°C for 15 min. The precipitate was then dried briefly and dissolved in water. Northern blotting was performed as described previously (Nasu et al., 1999a). Briefly, human IL-6 and IL-8 cDNA were labelled with [-32P]-dCTP using a random-primed DNA labelling kit (Amersham Life Science, Buckinghamshire, UK). The labelled probe was purified on a Sepharose-G50 column (Pharmacia, Piscataway, NJ, USA). Total RNA (20 µg) was subjected to electrophoresis in agarose/formaldehyde gels and transferred to nylon membranes (Hybond N, Amersham Life Science). The membranes were hybridized to a [32P]-radiolabelled probe for IL-6 or IL-8. Following hybridization, the membranes were washed and exposed at –70°C to Kodak XRP-5 film (Eastman Kodak Company, Rochester, New York) with intensifying screens (Eastman Kodak Company). We evaluated the expression of mRNA for ß-actin as an internal control. The relative levels of IL-6 and IL-8 mRNA were determined by image analysis of the autoradiograms using the public domain NIH image program 1.61 (developed at the US National Institutes of Health). The results were expressed as the ratio of IL-6 and IL-8 mRNA signals to the corresponding ß-actin mRNA signals. The same experiments of Northern blot were repeated three times. We did not perform Northern blot analysis for MCP-1 and M-CSF, because cDNAs for these cytokines were unavailable.
Statistical analysis
Data are presented as mean ± SD of triplicate samples from four separate representative experiments and were analysed using Bonferroni/Dunn test with StatView 4.5 (Abacus Concepts, Berkeley, CA, USA). P < 0.05 was considered to be statistically significant.
Results
Cytokine concentrations in the culture media of ESC and MaMi cells
Concentrations of IL-6, IL-8, MCP-1 and M-CSF in the cell-free culture media were all below the limit of detection. As shown in Figure 1, small amounts of IL-6, IL-8, MCP-1 and M-CSF were detected in the culture medium of non-stimulated ESC incubated for 24 h. The concentrations of IL-6, IL-8, MCP-1 and M-CSF increased with the addition of increasing amounts of recombinant human IL-4. There was no effect on the production of IL-6 and MCP-1 at a concentration of 0.001 ng/ml IL-4, but at that concentration, there was a weak stimulated production of IL-8 and M-CSF. IL-4 had a strong effect on the secretion of IL-6 (25-fold increase) and of MCP-1 (12-fold increase) at higher concentrations. In contrast, the stimulatory effects on IL-8 and M-CSF were both relatively weak: 2.5-fold increase for IL-8 and 2-fold increase for M-CSF.
|
As shown in Figure 2
, small amounts of IL-6, IL-8, MCP-1 and M-CSF were also detected in the supernatant of non-stimulated MaMi cells after incubation for 24 h. The concentrations of IL-6, IL-8, MCP-1 and M-CSF increased with the addition of increasing amounts of recombinant human IL-4. A concentration of 0.001 ng/ml IL-4 showed a weak effect on IL-6, IL-8, MCP-1 and M-CSF production, but exerted a strong effect on the secretion of both IL-6 (7-fold increase) and IL-8 (7-fold increase) at higher concentrations. Its stimulatory effects on MCP-1 and M-CSF were relatively weak (2.5-fold increase in MCP-1 and 2.5-fold increase in M-CSF). While the detailed results differed between the ESC and MaMi cells, the effects of IL-4 on their production of cytokines were almost identical. IL-4 did not affect the cell number in these experiments.
|
mRNA expression for IL-6 and IL-8 by ESC
Only a weak expression of IL-6 and IL-8 mRNA was detected in non-stimulated ESC. In response to IL-4, a dose-dependent increase in the expression of mRNA for IL-6 and IL-8 was observed (Figure 3
).
|
Discussion
The present study is the first to demonstrate that IL-4 enhances the production of IL-6, IL-8, MCP-1 and M-CSF by cultured ESC. We did not evaluate the expression of IL-4 receptor in ESC and the mechanism of transcriptional regulation of these cytokines by IL-4 is still unknown. However, these observations indicate that the ESC could be a cellular target for IL-4. Although IL-4 itself is not a chemoattractant for immunocompetent cells, the IL-4-induced release of IL-6, IL-8 and MCP-1 by ESC could lead to the accumulation of neutrophils, lymphocytes and monocytes in the endometrium.
IL-4 has been reported to modulate the production of other cytokines (Brantschen et al., 1989; Henschler et al., 1990; Standiford et al., 1990) and the modulatory effect has been suggested to be celland stimulus-specific; IL-4 down-regulates the production of IL-6 by human peripheral blood mononuclear cells (Te Velde et al., 1990) and by macrophages (Yanagawa et al., 1991); the production of IL-8 by neutrophils (Wertheim et al., 1993), monocytes (Standiford et al., 1990) and endothelial cells (Chen and Manning, 1996), and the production of M-CSF by monocytes (Gruber et al., 1994). In contrast, IL-4 has been shown to enhance the production of IL-6 by resting human B lymphocytes (Smeland et al., 1989), keratinocytes (Kupper et al., 1989), bronchial epithelial cells (Striz et al., 1999a), endothelial cells (Colotta et al., 1992; Chen and Manning, 1996) and skin fibroblasts (Feghali et al., 1992); the production of IL-8 by mast cells (Buckley et al., 1995) and bronchial epithelial cells (Striz et al., 1999b); the production of MCP-1 by endothelial cells (Colotta et al., 1992), and the production of M-CSF by embryonic lung fibroblasts and bone marrow fibroblasts (Henschler et al., 1990). We recently demonstrated that IL-4 inhibited, whereas IFN- enhanced, the TNF--stimulated production of RANTES (regulated upon activation, normal T cell expressed and secreted), a CC chemokine, by ESC (Arima et al., 2000). IFN-, an immunomodulatory Th1-type of cytokine, has recently been reported to stimulate the expression by ESC of IL-6, MCP-1 and M-CSF, but inhibits their expression of IL-8 (Nasu et al., 1998b). Our results suggest that IL-4 and IFN- have similar effects on the production of some cytokines by ESC. Thus, at least in our model system, the Th1/Th2 concept is probably too simplistic to explain some of the clinical and local processes.
The limitation of our study is the exclusion of the effects of ovarian steroid hormones, since ESC undergo morphological and functional changes during decidualization in early pregnancy. We employed ESC decidualized in vitro to evaluate the effects of IL-4 on decidualized ESC, however, decidualization itself markedly induced IL-6, IL-8, MCP-1 and M-CSF production as previously described (Hatayama et al., 1994; Kariya et al., 1994; Arici et al., 1996). We also could not find any significant effects of IL-4 on the production of these cytokines by decidualized ESC (data not shown). In addition, the immune response may be a continuum in which a complicated spectrum of responses and effects exist at the feto–maternal interface. More information is needed on the site, rate, spectrum, and regulation of cytokine production by T-cells and other immunocompetent cells in the mother and fetus to understand more fully the role of cytokines in successful pregnancy.
In summary, we here demonstrate that IL-4 up-regulates the production of IL-6, IL-8, MCP-1, and M-CSF by cultured ESC. It is suggested that the IL-4 produced by both the decidual tissue and the developing embryo may be involved in attracting and activating various immune effector cells in the feto–maternal interface by regulating the production of these cytokines produced by ESC as part of the feto–maternal cytokine network. These observations may provide insights into the mechanism involving the recruitment of inflammatory cells during normal and pathological human reproductive processes.
Acknowledgments
This work was supported in part by the Ministry of Education, Science and Culture of Japan Grant-in-Aid 11770945 (to K.Nasu) and 09671699 (to I.Miyakawa) for Scientific Research.
Notes
1 To whom correspondence should be addressed. E-mail: NASU{at}oita-med.ac.jp 
References
Arici, A., Head, J.R., MacDonald, P.C. et al. (1993) Regulation of interleukin-8 gene expression in human endometrial cells in culture. Mol. Cell. Endocrinol., 94, 195–204.[ISI][Medline]
Arici, A., MacDonald, P.C. and Casey, M.L. (1995) Regulation of monocyte chemotactic protein-1 gene expression in human endometrial stromal cells in cultures. Mol. Cell. Endocrinol., 107, 189–197.[ISI][Medline]
Arici, A., MacDonald, P.C. and Casey, M.L. (1996) Progestin regulation of interleukin-8 mRNA levels and protein synthesis in human endometrial stromal cells. J. Steroid Biochem. Mol. Biol., 58, 71–76.[ISI][Medline]
Arima, K., Nasu, K., Narahara, H. et al. (2000) Effects of lipopolysaccharide and cytokines on production of RANTES by cultured human endometrial stromal cells. Mol. Hum. Reprod., 6, 246–251.
Boehm, K.D., Kelley, M.F., Ilan, J. et al. (1989) The interleukin 2 gene is expressed in the syncytiotrophoblast of the human placenta. Proc. Natl Acad. Sci. USA., 86, 656–660.
Brantschen, S., Gauchat, J.-F., De Weck, A.L. et al. (1989) Regulatory effect of recombinant interleukin (IL)3 and IL4 on cytokine gene expression of bone marrow and peripheral blood mononuclear cells. Eur. J. Immunol., 19, 2017–2023.[ISI][Medline]
Buckley, M.G., Williams, C.M.M., Thompson, J. et al. (1995) IL-4 enhances IL-3 and IL-8 gene expression in a human leukemic mast cell line. Immunology, 84, 410–415.[ISI][Medline]
Chard, T. (1995) Cytokines in implantation. Hum. Reprod. Update, 1, 385–396.
Chen, C.C. and Manning, A.M. (1996) TGF-ß1, IL-10 and IL-4 differently modulate the cytokine-induced expression of IL-6 and IL-8 in human endothelial cells. Cytokine, 8, 58–65.[ISI][Medline]
Colotta, F., Sironi, M., Borre, A. et al. (1992) Interleukin 4 amplifies monocyte chemotactic protein and interleukin 6 production by endothelial cells. Cytokine, 4, 24–28.[ISI][Medline]
De Moraes-Pinto, M.I., Vince, G.S., Flanagan, B.F. et al. (1997) Localization of IL-4 and IL-4 receptors in the human term placenta, decidua and amniochorionic membranes. Immunology, 90, 87–94.[ISI][Medline]
Feghali, C.A., Bost, K.L., Boulware, D.W. et al. (1992) Human recombinant interleukin-4 induces proliferation and interleukin-6 production by cultured human skin fibroblasts. Clin. Immunol. Immunopathol., 63, 182–187.[ISI][Medline]
Gruber, M.F., Williams, C.C. and Gerrard, T.L. (1994) Macrophage-colony-stimulating factor expression by anti-CD45 stimulated human monocyte is transcriptionally up-regulated by IL-1ß and inhibited by IL-4 and IL-10. J. Immunol., 152, 1354–1361.[Abstract]
Hatayama, H., Kanzaki, H., Iwai, M. et al. (1994) Progesterone enhances macrophage colony-stimulating factor production in human endometrial stromal cells in vitro. Endocrinology, 135, 1921–1927.[Abstract]
Haynes, M.K., Jackson, L.G., Tuan, R.S. et al. (1993) Cytokine production in first trimester chorionic villi: detection of mRNAs and protein products in situ. Cell. Immunol., 151, 300–308.[ISI][Medline]
Henschler, R., Mantovani, L., Oster, W. et al. (1990) Interleukin-4 regulates mRNA accumulation of macrophage-colony stimulating factor by fibroblasts: synergism with interleukin-1ß. Br. J. Haematol., 76, 7–11.[ISI][Medline]
Jones, C.A., Williams, K.A., Finlay-Jones, J.J. et al. (1995) Interleukin 4 production by human amnion epithelial cells and regulation of its activity by glycosaminoglycan binding. Biol. Reprod., 52, 839–847.[Abstract]
Kariya, M., Kanzaki, H., Hanamura, T. et al. (1994) Progesterone-dependent secretion of macrophage colony-stimulating factor by human endometrial stromal cells of nonpregnant uterus in culture. J. Clin. Endocrinol. Metab., 79, 86–90.[Abstract]
Kupper, T.S., Min, K., Sehgal, P. et al. (1989) Production of IL-6 by keratinocytes. Ann. N.Y. Acad. Sci., 557, 454–465.[ISI][Medline]
Marzi, M., Vigano, A., Trabbattoni, D. et al. (1996) Characterization of type 1 and type 2 cytokine production profile in physiologic and pathologic human pregnancy. Clin. Exp. Immunol., 106, 127–133.[ISI][Medline]
Matthiesen, L., Ekerfelt, C., Berg, G. et al. (1998) Increased numbers of circulating interferon--and interleukin-4-secreting cells during normal pregnancy. Am J. Reprod. Immunol., 39, 362–367.
Mosmann, T.R. and Sad, S. (1996) The expanding universe of T-cell subsets: Th1, Th2 and more. Immunol. Today, 17, 138–146.[ISI][Medline]
Mosmann, T.R., Cherwinski, H., Bond, M.W. et al. (1986) Two types of murine helper T cell clone. I. Definition according to profile of lymphokine activities and secreted proteins. J. Immunol., 136, 2348–2357.[Abstract]
Nasu, K., Ishida, T., Setoguchi, M. et al. (1995) Expression of wild-type and mutated rabbit osteopontin in Escherichia coli, and their effects on adhesion and migration of P388D1 cells. Biochem. J., 307, 257–265.
Nasu, K., Matsui, N., Narahara, H. et al. (1998a) MaMi, a human endometrial stromal sarcoma cell line that constitutively produces interleukin (IL)-6, IL-8, and monocyte chemoattractant protein-1. Arch. Pathol. Lab. Med., 122, 836–841.[ISI][Medline]
Nasu, K., Matsui, N., Narahara, H. et al. (1998b) Effects of interferon- on cytokine production by endometrial stromal cells. Hum. Reprod., 13, 2598–2601.
Nasu, K., Narahara, H., Matsui, N. et al. (1999a) Platelet-activating factor stimulates cytokine production by human endometrial stromal cells. Mol. Hum. Reprod., 5, 548–553.
Nasu, K., Sugano, T., Matsui, N. et al. (1999b) Expression of hepatocyte growth factor in cultured human endometrial stromal cells is induced through a protein kinase C-dependent pathway. Biol. Reprod., 60, 1183–1187.
Piccinni, M.-P., Beloni, L., Livi, C. et al. (1998) Defective production of both leukemia inhibitory factor and type 2 T-helper cytokines by decidual T cells in unexplained recurrent abortions. Nature Med., 4, 1020–1024.[ISI][Medline]
Raghupathy, R. (1997) Th1-type immunity is incompatible with successful pregnancy. Immunol. Today, 18, 478–482.[ISI][Medline]
Smeland, E.B., Blomhoff, H.K., Funderud, S. et al. (1989) Interleukin 4 induces selective production of interleukin 6 from normal human B lymphocytes. J. Exp. Med., 170, 1463–1468.
Standiford, T.J., Strieter, R.M., Chensue, S.W. et al. (1990) IL-4 inhibits the expression of IL-8 from stimulated human monocytes. J. Immunol., 145, 1435–1439.[Abstract]
Striz, I., Mio, T., Adachi, Y. et al. (1999a) IL-4 and IL-13 stimulate human bronchial epithelial cells to release IL-8. Inflammation, 23, 545–555.[ISI][Medline]
Striz, I., Mio, T., Adachi, Y. et al. (1999b) Th2-type cytokines modulate IL-6 release by human bronchial epithelial cells. Immunol. Lett., 70, 83–88.[ISI][Medline]
Tabibzadeh, S. (1994) Cytokines and the hypothalamic–pituitary–ovarian–endometrial axis. Hum. Reprod. Update, 9, 947–967.
Te Velde, A.A., Huijbens, R.J., Heije, K. et al. (1990) Interleukin-4 (IL-4) inhibits secretion of IL-1 beta, tumor necrosis factor alpha, and IL-6 by human monocytes. Blood, 76, 1392–1397.
Wegmann, T.G., Lin, H., Guilbert, L. et al. (1993) Bidirectional cytokine interactions in the maternal–fetal relationship: Is successful pregnancy a Th2 phenomenon? Immunol. Today, 14, 353–356.[ISI][Medline]
Wertheim, W.A., Kunkel, S.L., Standiford, T.J. et al. (1993) Regulation of neutrophil-derived IL-8: the role of prostaglandin E2, dexamethasone, and IL-4. J. Immunol., 151, 2166–2175.[Abstract]
Yanagawa, H., Sone, S., Sugihara, K. et al. (1991) Interleukin-4 downregulates interleukin-6 production by human alveolar macrophages at protein and mRNA levels. Microbiol. Immunol., 35, 879–893.[ISI][Medline]
Submitted on October 2, 2000; accepted on December 21, 2000.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  R. Li, X. Luo, Q. Pan, I. Zineh, D. F. Archer, R.S. Williams, and N. Chegini Doxycycline alters the expression of inflammatory and immune-related cytokines and chemokines in human endometrial cells: implication in irregular uterine bleeding Hum. Reprod., October 1, 2006; 21(10): 2555 - 2563. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. S. Razzaque, B. S. Ahmed, C. S. Foster, and A. R. Ahmed Effects of IL-4 on Conjunctival Fibroblasts: Possible Role in Ocular Cicatricial Pemphigoid Invest. Ophthalmol. Vis. Sci., August 1, 2003; 44(8): 3417 - 3423. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. Sun, K. Nasu, J. Fukuda, S. Mine, M. Nishida, and I. Miyakawa Expression of macrophage inflammatory protein-3{alpha} in an endometrial epithelial cell line, HHUA, and cultured human endometrial stromal cells Mol. Hum. Reprod., October 1, 2002; 8(10): 930 - 933. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||