The involvement of T lymphocytes in the pathogenesis of endometriotic tissues overgrowth in women with endometriosis

BACKGROUND: Endometriosis, uncontrolled proliferation of ectopic and eutopic endometriotic tissues, is common in women at reproductive age, and may affect fertility. The role of macrophages in the pathogenesis is well proved, but engagement of T cells in the pathogenesis of endometriosis is a matter of controversy. AIMS: T-cell involvement in the pathogenesis of endometriosis was the objective of our study performed on women aged 24-46 years with diagnosed endometriosis. All the patients that were studied underwent diagnostic laparoscopy. METHODS: We evaluated the distribution of T-lymphocyte subpopulations in peripheral blood (PB), peritoneal fluid (PF) and in endometriotic tissues (ET), as well as cytokines [interleukin (IL)-2, IL-4, IL-10, IL-12, interferon (IFN)-gamma] production by peripheral blood lymphocytes. IFN-gamma, tumor necrosis factor (TNF)-alpha, IL-4 and IL-6 were investigated for their intracellular presence. The experiments were carried out before and after 6 months treatment with the GnRH-Analogous Goserelin (Zeneca Pharmaceuticals). The number of performed investigations is presented. Statistical analysis was performed using Statistica/Win 5.0 software and Student''s t-test, the paired Student t-test and Fisher''s exact test when appropriate. RESULTS: We have compared the lymphocyte subset re-distribution with regard to the American Fertility Society (AFS) stages and scores, but no differences were observed. The significant increase in CD4:CD8 ratio, the decrease in the number of natural killer (NK) cells in PB and the decrease in CD4:CD8 ratio in PF and ET of women with endometriosis was noted. The diminished IFN-gamma secretion by phytohemagglutinim (PHA)-stimulated lymphocytes in vitro derived from women with endometriosis and increased IL-4 production may be responsible for defective immunosurveillance against overgrowth of endometriotic tissues. The diminished NK cells number in PB of women with endometriosis argues for such a hypothesis. The increased deposits of proinflammatory IL-6 and TNF-alpha in the T lymphocytes of women with endometriosis may be related to T-regulatory lymphocyte function and their inability to suppress cell proliferation in endometriosis. GnRH-Analogous Goserelin treatment normalises cytokine production and induces patient recovery. CONCLUSIONS: The significant functional and phenotypic differences between the lymphocytes from healthy women and women with endometriosis were noted. The diminished IFN-gamma production in relation to decreased NK cells number and the increased IL-4 production before the treatment and normalisation after the treatment suggest the involvement of the deregulated T-cell system in the growth stimulation and recruitment of endometriotic cells. The increased CD4:CD8 ratio, IL-6, TNF-alpha deposits and diminished anti-inflammatory IL-10 production by lymphocytes may participate in the pathogenesis of endometriosis, and may secondarily affect the monocyte/macrophage function.     

Direct stimulation of cytokines (IL-1 beta, TNF-alpha, IL-6, IL-2, IFN-gamma and GM-CSF) in whole blood. I. Comparison with isolated PBMC stimulation.

Production of interleukin 1 beta (IL-1 beta), interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-alpha), interleukin 2 (IL-2), interferon gamma (IFN-gamma) and granulocyte-macrophage colony-stimulating factor (GM-CSF) after stimulation by lipopolysaccharide (LPS) and phytohemagglutinin (PHA) was studied in 1/10 diluted whole blood (WB) culture and in peripheral blood mononuclear cell (PBMC) culture. Cytokines IL-1 beta, TNF-alpha and IL-6 are preferentially stimulated by LPS whereas IL-2, IFN-gamma and GM-CSF are stimulated by PHA. Combination of 5 micrograms/ml PHA and 25 micrograms/ml LPS gave the most reliable production of the six cytokines studied. IL-1 beta, TNF-alpha and IL-6 represent a homogeneous group of early-produced cytokines positively correlated among themselves and with the number of monocytes in the culture (LeuM3). Furthermore, IL-1 beta was negatively correlated with the number of T8 lymphocytes. IL-2, IFN-gamma and GM-CSF represent a group of late-produced cytokines. Kinetics and production levels of IL-6 and GM-CSF are similar in WB and PBMC cultures. In contrast, production levels of TNF-alpha and IFN-gamma are higher in WB than in PBMC whereas production levels of IL-6 and IL-2 are lower in WB than in PBMC. Individual variation in responses to PHA + LPS was always higher in PBMC cultures than in WB cultures. The capacity of cytokine production in relation to the number of mononuclear cells is higher in WB, or in PBMC having the same mononuclear cell concentration as WB, than in conventional cultures of concentrated PBMC (10(6)/ml). Because it mimics the natural environment, diluted WB culture may be the most appropriate milieu in which to study cytokine production in vitro.     

Interleukin-18 enhances the production of interferon-gamma (IFN-gamma) by allergen-specific and unspecific stimulated cord blood mononuclear cells

BACKGROUND: IL-18 is a pleiotropic cytokine involved in the polarisation of T-cell response. This study was performed to determine whether or not IL-18 is detectable in phytohemagglutinin (PHA) or betalactoglobulin (BLG) stimulated supernatants of cord blood mononuclear cells (CBMC) and to study the in vitro effect of IL-18 on the interferon (IFN)-gaamma and IL-13 release of CBMC of healthy neonates. METHODS: CBMC of neonates were isolated by Ficoll density centrifugation. The cytokines IFN-gamma, IL-13 and IL-18 in the cell culture supernatants were measured using the ELISA technique following stimulation with a unspecific (PHA 20 microg/ml) and an allergen-specific stimulus (BLG 25 microg/ml). In order to study the in vitro effect of IL-18, CBMC were stimulated either with medium alone or with IL-18, IL-18 + PHA and IL-18 + BLG. RESULTS: IL-18 levels in supernatants of CBMC were low and did not vary significantly between unstimulated and PHA or BLG stimulated cell cultures (median 21.4; 23.5 and 15.5 pg/ml, respectively). IFN-gamma and IL-13 levels were significantly higher in response to PHA and BLG (PHA: IFN-gamma, 6154; IL-13, 4357; BLG: IFN-gamma, 801; IL-13, 249 pg/ml) compared to unstimulated cell cultures. The addition of IL-18 to PHA or BLG stimulated CBMC significantly enhanced the IFN-gamma release (PHA: 6154; PHA + IL-18: 13474, p = 0.0001; BLG: 801; BLG + IL-18: 1077, p = 0.008). In comparison to incubation without IL-18, the release of IL-13 was invariable or even reduced, when CBMC were stimulated with PHA + IL-18 (4026, p = 0.16) or BLG + IL-18 (124, p = 0.0001) compared to stimulation of CBMC with PHA (4357 pg/ml) or BLG (249 pg/ml) alone. CONCLUSIONS: IL-18 is detectable in supernatants of CBMC. We observed a significant effect of IL-18 + PHA as well as IL-18 + BLG on IFN-gamma release in vitro. Based on our findings we conclude that IL-18 could act as a strong TH1-inducing factor on stimulated CBMC also in vivo.     

Antiproliferative effect of IFN-gamma in immune regulation. III. Differential selection of TH1 and TH2 murine helper T lymphocyte clones using recombinant IL-2 and recombinant IFN-gamma

Supernatants collected after primary or secondary stimulation of spleen cells contain different arrays of lymphokines. Primary supernatants from spleen cells stimulated with Con A or allogeneic spleen cells (MLC-SF) contain IL-2 but little IL-4 or IGN-gamma; in contrast, secondary MLC-SF contains IL-2 as well as substantial IL-4 and IFN-gamma. Our laboratory previously had always used secondary MLC-SF for cloning T cells, and had routinely obtained TH1 helper T lymphocyte clones. In the present study, when primary Con A-SF was used as source of growth factors, TH2 and not TH1 clones were preferentially derived. Considering the possibility that IFN-gamma may be one important factor in determining whether TH1 or TH2 clones are preferentially obtained, clone derivation was then performed either in the presence of rIL-2 or rIL-2 plus rIFN-gamma. The majority of clones derived using rIL-2 alone were TH2 cells, whereas the majority of clones derived using rIL-2 plus rIFN-gamma were TH1 cells. Using either procedure, some clones were obtained that produced IL-2, IL-4, and IFN-gamma. These data are consistent with our previous observations that IFN-gamma inhibits the proliferation of TH2 but not TH1 clones, and suggest that the presence of IFN-gamma during an immune response would result in the preferential expansion of helper T lymphocytes of the TH1 phenotype. Our procedure for the differential selection of TH1 and TH2 clones reactive with the same Ag should be useful for designing in vitro systems for studying the function of these cell subsets in specific immune responses.     

Influences of orally administered lactoferrin on IFN-gamma and IL-10 production by intestinal intraepithelial lymphocytes and mesenteric lymph-node cells.

Intestinal mucosal immunity plays an important role in mucosal and systemic immune responses. We investigated the influences of orally administered bovine lactoferrin (LF) on cytokine production by intestinal intraepithelial lymphocytes (IEL) and mesenteric lymph-node (MLN) cells, especially T cells. Bovine LF or bovine serum albumin (control) was administered to mice once daily for 3 d. After 24 h from the last administration, IEL of the jejunum and ileum and MLN cells were isolated. These cells were cultured with and without the anti-T-cell-receptor antibody, and then the culture supernatants were assayed for cytokines with ELISA. Oral LF did not affect the ratio of T-cell subpopulations in IEL and MLN; however, LF enhanced both interferon (IFN)-gamma and interleukin (IL)-10 production by unstimulated IEL and by IEL stimulated with the alphabeta T-cell receptor but not with the gammadelta T-cell receptor. LF also enhanced both IFN-gamma and IL-10 production by stimulated and unstimulated MLN cells. The production level of IFN-gamma by MLN cells was correlated with that of IL-10. These results suggest that oral LF enhances the production of both Th1-type and Th2/Tr-type cytokines in the small intestine of healthy animals.     

Cytokine secretion by decidual lymphocytes in transient hypertension of pregnancy and pre-eclampsia

BACKGROUND: Transient hypertension (TH) and preeclampsia (PE) are believed to have different pathophysiology. However, 15-25% of pregnant women initially diagnosed as having TH develop PE. To clarify the immuno-pathogenetical connections between the two syndromes, we studied the pattern of T helper cell (Th)1/Th2 cytokine balance disturbances existing inside maternal decidua in normal pregnancy (NP) and pregnancies complicated with TH and PE. METHODS: Third-trimester decidual tissue was obtained by curettage of uterine cavity during elective caesarean sections in NP (n = 11), TH (n = 17) and PE (n = 21) patients. Cell suspensions were prepared by an electromechanical dispersal method and centrifugated using a standard gradient sedimentation technique. Isolated lymphocytes were placed in medium (RPMI 1640, 10% fetal calf serum, L-glutamine, penicillin, streptomycin) and cultured for 72 h with or without mitogen phytohaemaglutinine (PHA). The enzyme-linked immunosorbent assay method was used for estimation of interleukin (IL)-2, IL-4, IL-6, IL-10, IL-12 and interferon-gamma (IFN-gamma) in culture supernatant. STATISTICAL ANALYSIS: The Kruskal-Wallis and the Mann-Whitney U tests were used (p < 0.05). RESULTS: Both spontaneous and PHA-stimulated secretion of Th2-type cytokines IL-6 and IL-10 was decreased in PE patients compared with TH and NP patients. The concentration of Th1-type cytokine IFN-gamma was increased in patients suffering both from TH and PE. CONCLUSION: On the base of decidual cytokine secretion, both PE and TH are syndromes of local Th1/Th2 cytokine balance disturbances as compared with NP, and TH seems to be an intermediate step to PE.     

Antiretroviral treatment induces a shift to type-2 cytokine responses in HIV-1 infected pregnant women

We report on a cross-sectional study on proliferation and cytokine production (IFN-gamma, IL-12, IL-5 and TNF-alpha) by peripheral blood mononuclear cells (PBMC), activated or not with phytohemagglutinin (PHA) in HIV-1-infected pregnant women, untreated or treated with zidovudine. We compared the results with healthy women, either pregnant or not, and with HIV-1-infected, non-pregnant women. The most significant results indicate that basal IL-5 production in HIV-1-infected pregnant women was higher than in the rest of the groups, being even higher in the zidovudine-treated than in the untreated group. IL-5 and TNF-alpha production by PHA-activated PBMC was also higher in HIV-1 pregnant women than in controls and infected non-pregnant women. IFN-gamma production was much higher in healthy women than in the other groups. Finally, the IFN-gamma/IL-5 (Th1-type/Th2-type-cytokine) ratio was lower in HIV-infected than in uninfected groups. Zidovudine treatment reduced basal IL-12 and increased PHA-stimulated IL-5 production. Our results indicate that both HIV-1 infection and pregnancy favored a Th2-type response by T cells. Interestingly, zidovudine-treated pregnant women had a significantly higher Th2-type response than untreated ones.     

Hemorrhage produces abnormalities in lymphocyte function and lymphokine generation

Hemorrhage has been shown to produce abnormalities in lymphocyte function, particularly in the proliferative response to mitogens such as PHA and Con A. In order to better examine the hemorrhage-induced alterations in immune function, we determined the effects of blood loss in mice without any surgical manipulation on lymphocyte populations and subpopulations, cellular activation, and lymphokine production. Hemorrhage induced no changes in cell numbers in the spleen, thymus, lymph nodes, and bone marrow. No alterations in the relative percentages of B (B220+, mu+) and T (Lyt-1+, Lyt-2+, T3+, L3T4+) cell subpopulations were found in any organ after blood loss. Significant decreases in splenocyte proliferation in response to Con A, IL-2R expression and blast formation occurred after hemorrhage. IFN-gamma production increased 24 and 48 h post hemorrhage. Decreases in IL-2, IL-3, and IL-5 generation were present 2 h after blood loss. IL-2 production remained significantly decreased for 48 h posthemorrhage, then increased to more than twice normal levels 72 h posthemorrhage, and subsequently returned to prehemorrhage values. These results demonstrate that hemorrhage produces widespread alterations in immune function without affecting lymphocyte population and subpopulation numbers.     

Competition of IL-1 and IL-1ra determines lymphocyte response to delayed stimulation with PHA.

BACKGROUND: Human peripheral blood mononuclear cells (PBMC) left in microcultures for 24h without mitogen do not respond to subsequent stimulation with PHA. They regain reactivity if the native culture medium is absorbed with other party lymphocytes or partially replaced with the medium from a PHA-stimulated culture. The observations suggest that, during the incubation, some inhibitory agent had accumulated in the culture medium. AIM: The study was performed to determine the nature of the observed phenomenon in respect of the possible role of monocytes and their products IL-1 and IL-1 receptor antagonist (IL-1ra), and to test for immunodiagnostic purposes the significance of quantifying the lymphocyte response to delayed stimulation with PHA in patients suffering from inflammatory prosesses. METHODS: Lymphocyte response to delayed stimulation with PHA, calculated as the lymphocyte-monokine interaction (LM) index, was determined in the microcultures of PBMC isolated from the blood of healthy donors or of patients with acute tonsilitis. The values of LM indices were compared with the ratios of IL-1ra/IL-1beta concentration estimated by enzyme-linked immunosorbent assay method in the culture supernatants. The influences of exogenous IL-1beta, IL-1ra, anti-IL1ra antibodies and antibiotic cefaclor on the monokine concentrations and on the values of LM index were tested. RESULTS AND CONCLUSIONS: The results show that the level of lymphocyte response to delayed stimulation with PHA (LM index) is inversely proportional to the ratio of IL-1ra/IL-1beta concentration in the culture. The low LM values at high IL-1ra/IL-1beta ratios in PBMC cultures from healthy donors, reversed proportions found in patients'' PBMC (acute tonsilitis), and the cefaclor-induced reduction of LM value with correlated increase of the IL-1ra/IL-1beta ratio suggest that the LM assay may prove to be useful for immunodiagnostic purposes.     

Reduction in the number of UCHL-1+ cells and IL-2 production in the peripheral blood of patients with visceral leishmaniasis.

PBMC from patients with visceral leishmaniasis (VL), before and after successful antimony therapy, were analyzed for their phenotypes and for their ability to produce IL-2 and IFN-gamma and to proliferate against PHA and leishmanial Ag. In agreement with results of earlier studies, PBMC from active VL patients showed a markedly reduced proliferative response and IL-2 and IFN-gamma production, compared with those of healthy controls. The levels of CD4+ and CD8+ T cells were within the normal range, but there was a significant decrease in UCHL-1+ cells (helper-inducer), compared with healthy individuals. The inhibited cellular responses, and lymphokine secretion and decreased level of UCHL-1+ cells in the PBMC of the VL patients returned to the normal range after successful chemotherapy. PBMC from active VL patients were fractionated into adherent cells and nonadherent cells, and the non-adherent were further fractionated into UCHL-1+ and UCHL-1- subpopulations. Results from cell depletion and reconstitution experiments suggest that the IL-2 production by nonadherent cells stimulated with PHA was inhibited by adherent cells, but the IL-2 production by nonadherent cells in response to specific Ag was not. In contrast, UCHL-1- cells seem to mediate the inhibition of Ag-driven IL-2 production by nonadherent cells but not mitogen-stimulated IL-2 secretion by nonadherent cells. Ag-specific IL-2 production principally involves UCHL-1+ cells.     

Decreased response to IL-12 and IL-18 of peripheral blood cells in rheumatoid arthritis

Inflamed synovium of rheumatoid arthritis (RA) has been associated with a T helper (Th)1 cytokine profile but the blood situation remains to be clarified. We studied the differential IFN-gamma producing activity of peripheral blood mononuclear cells (PBMCs) from RA patients (RA-PBMCs) and from healthy controls (H-PBMCs) in response to IL-12 and IL-18. RA-PBMCs had a decreased IFN-gamma production in response to IL-12 and IL-18 when compared with H-PBMCs. RA-PBMCs activated with phytohemagglutinin and phorbol 12-myristate 13-acetate showed an increased sensitivity to IL-12 and IL-18, but still the RA-PBMC response was lower. IL-18 increased IL-12-stimulated IFN-gamma production from RA synovium cells obtained after collagenase digestion more effectively than that of RA- or H-PBMCs. A specific inhibitor of IL-18 bioactivity, IL-18-binding protein (IL-18BP), down-regulated IL-12-induced IFN-gamma production by RA- or H-PBMCs and had a remarkable effect on RA synovium cells. In conclusion, RA disease combines a polarized immune response with an active Th1 in inflamed joints and a reduced Th1 pattern in peripheral circulation.     

Stimulation of AIDS lymphocytes with calcium ionophore (A23187) and phorbol ester (PMA): studies of cytoplasmic free Ca, IL-2 receptor expression, IL-2 production, and proliferation

We have studied whether the decreased lymphocyte proliferative responses of AIDS lymphocytes to stimulation by mitogens and antigens may be overcome when challenged with a combination of calcium ionophore A23187 and phorbol ester PMA. Comparison of the proliferative response of lymphocytes from nine patients with AIDS with the response of lymphocytes from nine control subjects showed that the response of AIDS lymphocytes was severely decreased when stimulated with PHA and no further response could be achieved by stimulation with A23187/PMA. On the other hand, no significant difference between the PHA-induced rise of cytoplasmic free calcium concentration ([Ca2+]1) in normal and AIDS lymphocytes was observed. The percentage of cells expressing IL-2 receptors (CD25) was also normal both after addition of PHA and after addition of A23187/PMA and the expression was normal on both CD4 and CD8 cells. The production of IL-2 in normal lymphocytes stimulated with A23187/PMA was 33 times higher than that after stimulation with PHA. In AIDS lymphocytes the production of IL-2 induced by all activators was severely decreased compared to control subjects, although the production of IL-2 after stimulation with A23187/PMA was higher than that in control lymphocytes after stimulation with PHA. The present study shows that a direct activation of protein kinase C combined with mobilization of cytoplasmic calcium does not overcome the lymphocyte proliferative deficiency of AIDS lymphocytes.     

Suppression of T lymphocyte function by measles virus is due to cell cycle arrest in G1

Measles virus suppresses T lymphocyte functions in vitro. When measles virus-infected T lymphocytes are stimulated with PHA or 12-O-tetradecanoylphorbol-13-acetate, plus calcium ionophore, the cells secrete IL-2 and express the IL-2R or Tac Ag to a similar extent as uninfected cells, yet proliferation is reduced by 50 to 90%. Stimulated infected T cells also express the cell surface activation Ag 4F2, transferrin R, and HLA-DR. The secretion of IFN-gamma by infected T cells in response to PHA is not suppressed at 24 to 72 h after stimulation. Total RNA synthesis at 48 and 72 h after stimulation is reduced in infected T lymphocytes. Infectious measles virus progeny are produced during this interval. Thus infected T lymphocytes can become activated in response to mitogenic stimuli and the cells support efficient viral replication before the block in cell proliferation.     

Cytokine Quantification in the Supernatant of Mononuclear Cell Cultures and in Blood Serum from Patients with Jorge Lobo's Disease

Few studies are available about the participation of the immune response in the control or the development of Jorge Lobo's disease. Thus, the objective of the present study was to quantify macrophage and lymphocyte cytokines in the supernatant of cell cultures and in blood serum from patients with this disease. The study was conducted on 15 patients with the mycosis and on 15 healthy adult individuals (control group). Blood samples were collected in order to obtain serum and mononuclear cells. Monocytes were cultured for 24 h in the presence or absence of LPS and L. loboi, and lymphocytes were cultured for 48 h in the presence or absence of PHA and L. loboi. Cytokines IL-1beta, TNF-alpha and IL-6 were quantified by ELISA in the supernatants of monocyte cultures and in serum. Cytokines IL-2, IFN-gamma, IL-4 and IL-10 were quantified by FLISA in the supernatants of lymphocyte cultures and in serum. The quantification of the cytokines in the culture supernatant revealed a greater IL-4 and IL-6 production and lower IL-2 levels in patients compared to control. The production of IL-1beta, TNF-alpha, IL-10 and INF-gamma was similar in patients and controls. The mononuclear cells from patients with the non-localized form of the disease produced higher INF-gamma levels than those of patients with the localized form. The results suggest that patients with Jorge Lobo's disease show altered cytokine profiles represented by a predominance of the Th2 profile. However, further studies are needed to assess the participation of cytokines in the cell-fungus interaction in situ.     

IFN-beta inhibits the ability of T lymphocytes to induce TNF-alpha and IL-1beta production in monocytes upon direct cell-cell contact.

Tumour necrosis factor (TNF)-alpha and interleukin (IL-)1beta, essential players in the pathogenesis of immuno-inflammatory diseases, are strongly induced in monocytes by direct contact with stimulated T lymphocytes. The present study shows that the latter mechanism is inhibited by interferon (IFN)-beta. In co-cultures of autologous T lymphocytes and monocytes stimulated by phytohaemagglutinin (PHA), IFN-beta inhibited the production of TNF-alpha and IL-1beta by 88 and 98%, respectively, whereas the simultaneous production of IL-1 receptor antagonist (IL-1Ra), was enhanced two-fold. The latter effects of IFN-beta were independent of modulations in IFN-gamma, IL-4 and IL-10 production. When monocytes were activated by plasma membranes of stimulated T cells, IFN-beta slightly inhibited the production of TNF-alpha and IL-1beta, while enhancing 1.5-fold that of IL-1Ra. The latter effect correlated with the persistence of high steady-state levels of IL-1Ra mRNA after 24 h of activation. Membranes isolated from T lymphocytes that had been stimulated in the presence of IFN-beta displayed a 80% decrease in their capacity to induce the production of IL-1beta and TNF-alpha in monocytes, whereas IL-1Ra induction was decreased by only 32%. These results demonstrate that IFN-beta modulates contact-mediated activation of monocytes by acting on both T lymphocytes and monocytes, decreasing the ability of T lymphocytes to induce TNF-alpha and IL-1beta production in monocytes and directly enhancing the production of IL-1Ra in the latter cells.     

Modulation of IL-4-induced human IgE production in vitro by IFN-gamma and IL-5: the role of soluble CD23 (s-CD23)

IL-4 specifically induced IgE production by peripheral blood lymphocytes or by tonsil or spleen cells from healthy donors. IL-4-induced IgE synthesis was dependent on CD4+ T cells and monocytes and was blocked by IFN-gamma, IFN-alpha, and prostaglandin E-2 (PGE-2). These substances also inhibited IL-4-induced CD23 expression and subsequent release of soluble CD23 (s-CD23). In addition, IgE production was blocked by F(ab')2 fragments of an mAb against CD23. In contrast, IL-5 enhanced IL-4-induced IgE production, provided IL-4 was added at nonsaturating concentrations. This increase in IgE production correlated quantitatively with an enhanced release of s-CD23. Collectively, these results indicate that there is a correlation between s-CD23 release and IgE production. However, s-CD23 fractionated from supernatants of the lymphoblastoid cell line RPMI-8866 was ineffective in inducing IgE production in the absence of IL-4, but acted synergistically with suboptimal concentrations of IL-4. In addition, it is demonstrated that alloreactive T-cell clones produced varying concentrations of IL-4, IL-2, or IFN-gamma upon stimulation. Only supernatants of 2/4 of these T-cell clones induced a low degree of IgE synthesis, but in the presence of anti-IFN-gamma antibodies, all four supernatants induced a strong induction of IgE production. This IgE synthesis was blocked specifically by anti-IL-4 antibodies, indicating that IL-4 is the sole inducer of IgE synthesis. Our findings demonstrate that IL-4-induced IgE production involves complex interactions of T cells, B cells, and monocytes and is positively modulated by IL-5 and s-CD23 but down-regulated by IFN-gamma, IFN-alpha, and PGE-2, respectively.     

Prolactin enhances production of interferon-gamma,interleukin-12, and interleukin-10, but not of tumor necrosis factor-alpha,in a stimulus-specific manner

Prolactin, an anterior pituitary hormone, has been shown to have a role in immunomodulation. Some reports have shown the importance of prolactin in activating lymphocytes and macrophages, while in hyperprolactinemia patients, prolactin was found to decrease lymphocyte activation and natural killer function. In the present work, at physiological (15ng/ml) and stress-induced levels (30ng/ml) of prolactin, interferon-gamma (IFN-gamma) and interleukin (IL)-12 p70 levels, but not of IL-10 and tumor necrosis factor-alpha (TNF-alpha), increased significantly (p<0.05-0.006) in phytohemeagglutinin (PHA)+lipopolysaccharide (LPS)-stimulated whole blood. However, no such effect was observed at high concentrations of prolactin (100-300ng/ml). In addition, 15ng/ml of prolactin reversed hydrocortisone suppressive effect on IFN-gamma, IL-12 p70, and IL-10 production in PHA+LPS-stimulated whole blood. On the other hand, in LPS-stimulated whole blood, prolactin enhanced significantly (p=0.027) the production levels of IL-10, but not of IFN-gamma, IL-12 p70, and TNF-alpha, in non-concentration-dependent manner. These results suggest that prolactin modulates cytokine response during antigenic response, and this modulation is stimulus specific.     

Serum concentrations of androstenediol and androstenediol sulfate, and their relation to cytokine production during and after normal pregnancy

Since it is known that androstenediol (ADIOL) has potent immunoregulatory effects, changes in ADIOL levels during and after pregnancy might affect the maternal immune system. We examined serum concentrations of ADIOL and androstenediol 3-sulfate (ADIOLS) together with IFN-gamma and IL-4 production levels during pregnancy and after delivery up to 10-11 months postpartum. The subjects were 73 normal pregnant, 76 normal postpartum, and 28 normal non-pregnant women. ADIOL and ADIOLS were measured using EIA and GC/MS, respectively. The cytokine levels in the supernatant of whole-blood cultures stimulated with phorbol 12-myristate 13-acetate and ionomycin were measured using ELISA. ADIOL levels significantly decreased compared to non-pregnant levels in the first trimester (P < 0.05) and were reversed in the third trimester (P < 0.05). After pregnancy, ADIOL levels gradually declined, and a significant decrease was observed at 10-11 months postpartum (P < 0.05). ADIOLS levels were significantly lower in the third trimester (P < 0.05) and significantly higher at the first month postpartum (P < 0.001) compared to non-pregnant women. IFN-gamma and IL-4 levels decreased during pregnancy and subsequently increased postpartum. On the other hand, we found significant negative correlations between ADIOL concentrations and production levels of IFN-gamma (P < 0.05) or IL-4 (P < 0.05). These findings suggest that ADIOL may be involved in modifying the maternal immune response during and after pregnancy.