Soluble MHC class II-driven therapy for a systemic lupus erythematosus murine experimental in vitro and in vivo model

Taking into consideration the multiparametric nature of systemic lupus erythematosus (SLE), the severity and variability of symptoms and the lack of effective therapeutic approaches, this study took advantage of the recently described role of soluble major histocompatibility complex class II (sMHCII) molecules in maintaining tolerance to the organism and attempted to apply sMHCII proteins as a treatment to murine SLE experimental models in vitro as well as in vivo. After breaking tolerance to DNA in vitro, which was accompanied by development of specific anti-dsDNA antibodies, syngeneic or allogeneic sMHCII molecules, purified from healthy mouse serum, could significantly reduce the specific antibody levels and drive the system towards immunosuppression, as assessed by specific marker analysis on T cells and cytokine production by flow cytometry and ELISA, respectively. The in vivo experimental model consisted of pristane-induced SLE symptoms to BALB/c mice, which developed maximal levels of anti-dsDNA 2 months after pristane inoculation. Syngeneic or allogeneic sMHCII administration could alleviate pristane-induced symptoms, significantly decrease specific anti-dsDNA antibody production and develop immunosuppression to the host, as manifested by increase of CD4 + CTLA-4 +  and CD4 + CD25 +  cell populations in the spleen. Thus, the results presented in this study introduced the ability of sMHCII proteins to suppress specific autoantigen response, opening new areas of research and offering novel therapeutic approaches to SLE with expanding features to other autoimmune diseases.

Laser fabricated discontinuous anisotropic microconical substrates as a new model scaffold to control the directionality of neuronal network outgrowth

Patterning of neuronal outgrowth in vitro is important in tissue engineering as well as for the development of neuronal interfaces with desirable characteristics. To date, this has been achieved with the aid of micro- and nanofabrication techniques giving rise to various anisotropic topographies, either in the form of continuous or discontinuous structures. In this study we propose a currently unexplored geometry of a 3D culture substrate for neuronal cell growth comprising discontinuous subcellular microstructures with anisotropic geometrical cross-section. Specifically, using laser precision 3D micro/nano fabrication techniques, silicon substrates comprising arrays of parallel oriented elliptical microcones (MCs) were fabricated to investigate whether a discontinuous geometry comprising anisotropic features at the subcellular level could influence the alignment of peripheral nervous system cell populations. It was shown that both Schwann cells and axons of sympathetic neurons were parallel oriented onto the MCs of elliptical shape, while they exhibited a random orientation onto the MCs of arbitrary shape. Notably, this topography-induced guidance effect was also observed in more complex cell culture systems, such as the organotypic culture whole dorsal root ganglia (DRG) explants. Our results suggest that a discontinuous topographical pattern could promote Schwann cell and axonal alignment, provided that it hosts anisotropic geometrical features, even though the sizes of those range at the subcellular lengthscale. The laser-patterned arrays of MCs presented here could potentially be a useful platform for patterning neurons into artificial networks, allowing the study of neuronal cells interactions under 3D ex-vivo conditions.

Third Harmonic Generation microscopy as a reliable diagnostic tool for evaluating lipid body modification during cell activation: the example of BV-2 microglia cells

Nonlinear optical processes have found widespread applications in fields ranging from fundamental physics to biomedicine. In this study, we attempted to evaluate cell activation by using the Third Harmonic Generation (THG) imaging microscopy as a new diagnostic tool. The BV-2 microglia cell line with or without activation by lipopolysaccharide was chosen as a representative biological model. The results showed that THG imaging could discriminate between the control versus activated state of BV-2 cells not only as to THG signal intensity but also as to THG signal area, while verifying once more that the majority of the intracellular detected signal corresponds to lipid bodies. Since THG imaging is a real time, non-destructive modality and does not require any prior cell processing and staining, the results presented here provide an important tool for normal versus activated cell discrimination, which could be proved very useful in the study of inflammation.

Microconical silicon structures influence NGF-induced PC12 cell morphology

Micro-and nanofabrication techniques provide the opportunity to develop new types of cell culture platform, where the effect of various topographical cues on cellular functions such as proliferation and differentiation can be studied. In this study, PC12 cells were cultured on patterned silicon (Si) surfaces comprising arrays of microcones (MCs) exhibiting different geometrical characteristics and surface chemistries. It was illustrated that, in the absence of nerve growth factor (NGF), PC12 cells increased proliferation on all types of patterned surface, as compared to flat Si surfaces. However, in the presence of NGF, PC12 cells showed different responses, depending on the plating surface. Unlike low and intermediate rough MC surfaces, highly rough ones exhibiting large distances between MCs did not support PC12 cell differentiation, independently of the MCs' chemical coatings. These results suggest that the geometrical characteristics of MCs alone can influence specific cellular functions. Tailoring of the physical properties of arrays of Si MCs in order to identify which combinations of MC topologies and spatially defined chemistries are capable of driving specific cellular responses is envisaged.

Do maternity hospital practices support Greek mothers' decision to breastfeed?

AIM

Previous studies have shown that the conditions in Greek maternity hospitals do not support the right of mothers and their children to breastfeed. The aim of the present report was to investigate the degree that Greek maternity hospitals have adopted the 'Ten Steps to Successful Breastfeeding'.

METHODS

The study sample comprised 140 mothers living in Athens who had recently given birth and volunteered to fill in specific questionnaires.

RESULTS

40.5% of the mothers did not know what the first meal of their baby was. Regarding hospitals' practices, 68.3% of the mothers mentioned that artificial milk was brought in every meal of the neonate, while 63.6% believed that artificial milk was given to their child without their knowledge, despite the fact that they had already decided to breastfeed. Ninety percent of the mothers giving birth in public maternity hospitals and 60% delivering in private clinics mentioned that health professionals supported breastfeeding (p < 0.05).

CONCLUSIONS

It seems that in daily practice, Greece has not yet created an appropriate well informed and supportive environment in regard to breastfeeding.

Endometriosis and infertility: a multi-cytokine imbalance versus ovulation, fertilization and early embryo development

Endometriosis is tightly linked to infertility which is manifested at very early or more advanced stages of the gestational cycle. Alteration on the production of a great number of cytokines/growth factors can be accused for problems on ovum maturation, fertilization or implantation. Yet, macroscopically these stages are characterized by the inability of conception. A closer look of the cytokinic profile during the conceptional and early gestational cycle could, however, localize the problem and allow a therapeutic approach. In this commentary, going through the cytokine requirement during ovulation, fertilization and the early stages of pregnancy, it became possible to specifically define the harmful endometriosis-induced cytokines for each of the conceptional and early gestational stages. Thus, regulating the levels of interferon-γ and tumor necrosis-α will facilitate ovulation and fertilization, whereas adjusting the levels of interleukin-1β and colony stimulating gactor-1 will facilitate implantation.

Constitutive or induced elevated levels of l-carnitine correlate with the cytokine and cellular profile of endometriosis

During the past decade, accumulated evidence indicates an association between endometriosis and an alteration of humoral and cell-mediated immunity. While the role of L-carnitine in the regulation of energy metabolism is well established, it is only recently that L-carnitine has been recognized to modify the immune response in mice after in vitro or in vivo treatment. The present study has examined whether administration of L-carnitine to young female mice alters the percentage of immune cells in peritoneal exudates and the uterus as well as the levels of IFN-gamma, TNF-alpha, IL-2, IL-4, IL-6, VEGF, GM-CSF and IGF-I in blood serum, peritoneal fluid and supernatants of uterine cultured cells as tested by immunofluorescence or ELISA techniques, respectively, leading to a pathological disorder resembling human endometriosis. The results showed that, except from infertility, L-carnitine treatment resulted in a significant increase of macrophages and to a lesser degree an increase of T-cells, while elevated levels of IFN-gamma and TNF-alpha were detected in both serum and peritoneal fluid compared to controls. Although levels of L-carnitine measured in mouse serum samples using a radioisotopic method showed an increase as compared to controls, levels of acyl-L-carnitine measured in the murine peritoneal fluid samples showed a decrease similar to that measured in peritoneal fluid samples from patients with endometriosis in stage IV of the disease. These results indicate that L-carnitine administration to female mice alters the cellular and growth factor profile in the uterus and peritoneum towards a phenotypical pathology similar to that of clinical endometriosis.

The role of L-carnitine on a restricted number of myeloid leukemia progenitor cells: generation of atypical cell types

AIM

Since cellular maturation largely depends on lipid metabolism, we examined whether L-carnitine (L-C), a substance involved in these biochemical pathways, is able to promote differentiation of the promyelocytic cell line HL-60.

METHODS

Differentiation was assessed by marker analysis, morphology, immunohistochemistry, proliferation and cellular activity assays.

RESULTS

L-C increases HLA-DR and CD14 surface antigens, while morphologic and marker analysis of the treated cells reveals the presence of monocytes, neutrophiles and few dendritic cells. What is important, however, is the induction of cells that have an atypical to this pathway allure staining positive for the neurofilament 3A10 monoclonal antibody, specific for nerve cells and the anti-p75 (Nerve Growth Factor Receptor) monoclonal antibody. The events described concern active and, at the same time, not proliferative senescent cells.

CONCLUSIONS

L-C exerts its differentiation action on a certain fraction of the leukemic population yielding a non-negligible number of atypical for the myeloid lineage cells. These findings complement earlier and recent reports that describe the generation of cells of a different lineage irrelevant to their parent line of differentiation indicating that the hemopoietic pool appears to be the source of any kind of cell types according to the stimulus provided. Thus, in the context of the plasticity theory it appears that the HL-60 cell line also possess the potential to differentiate towards unexpected pathways.

Serum concentrations of growth factors in women with and without endometriosis: the action of anti-endometriosis medicines

Endometriosis is a common gynecologic syndrome of unknown etiology and pathogenesis. Growth factors and inflammatory mediators produced by peritoneal leukocytes have recently been postulated to participate in the pathogenesis of endometriosis. Angiogenic factors released from peritoneal macrophages may also play a role in the development of this disease. In the present study, we investigate the soluble levels of vascular endothelial growth factor (VEGF), epidermal growth factor-receptor (EGF-R), granulocyte/macrophage-colony stimulating factor (GM-CSF), Insulin-like growth factor-1 (IGF-1) and interferon-gamma (IFN-gamma) in the serum of 28 women with and 20 without endometriosis. We also compared these levels before, during and after treatment with danazol and leuprorelin acetate depot, the two therapeutic regiments of choice concerning this disease. We found that only sVEGF levels were higher in women with endometriosis in comparison to controls (P < 0.001) while sEGF-R is not present. GM-CSF, IGF-1 and IFN-gamma soluble levels are not affected in either healthy or endometriotic subjects. The 6-month treatment with danazol decreased sVEGF levels (P < 0.02) and increased sEGF-R levels (P < 0.001). These observations support the view that VEGF may be associated with the disease process and that danazol may bring sVEGF levels to a normal threshold. However, future studies will be focused on the anti-angiogenic control of the action of VEGF in patients with endometriosis.

T-regulatory cells: are we re-discovering T suppressors?

Regulatory T cells are shown to originate form the thymus and their role is to maintain self-tolerance to intra-thymic as well as extra-thymic self-antigens. Their mode of action, using in vivo and in vitro systems, has led to different conclusions as to the need of cell-cell interactions or regulation upon suppressive cytokines. The more we study regulatory T cells the more we find similarities to the old notion of the suppressor T cell network. The limited knowledge in molecular technology in the early 70s and 80s discouraged investigators to further scrutinize the issue and the terms T suppressors and contra-suppressors that were coined back then have been forgotten over the years. It is now time to remember the work of these investigators and attempt to explain their findings using the current knowledge and technology.

Serum-soluble human leucocyte antigen class I and class II concentrations as an alternative diagnostic test for determining immune indices required for normal pregnancies

The levels of maternal immunostimulation (required throughout the gestation period) and immunosuppression (needed from the 8th week to labour), as assessed by the mixed lymphocyte reaction (MLR), have been successfully correlated with the outcome of pregnancy. Our laboratory has recently reported that serum-soluble human leucocyte antigen (HLA) class I and II concentrations can be predictive for successful pregnancy outcome. In fact, there is a direct correlation between soluble class II concentrations and maternal immunostimulation because, as expected, these serum HLA concentrations are augmented in the first and second trimester of pregnancy and remain stable thereafter. By the same token, serum HLA class I concentrations are low during the first trimester, correlating with the required absence of immunosuppression, whereas they increase in subsequent trimesters as suppression becomes desirable for counteracting the maternal stimulation, which may otherwise become dangerous to the fetus. In this study, we present biological and statistical evidence that both states of maternal immunostimulation and immunosuppression, reflected by serum soluble HLA class II and class I antigens, do correlate with results obtained by standard MLR and can be predictive of pregnancy failure. The establishment of statistically significant correlations renders the measurement of soluble HLA a reliable test for determining the immunological status of the gestating woman. The unambiguous advantage of such an approach is that soluble HLA testing will no longer require the 1 week delay necessary to obtain MLR results, a period occasionally crucial for applying treatment to women whose immunological indices call for immediate therapeutic intervention.

L-carnitine accelerates the in vitro regeneration of neural network from adult murine brain cells

The development, growth and regeneration of nerve cells remain an unresolved issue. The up-to-date reported brain repair mechanisms are numerous and evidence suggests that, apart from the required trophism, tropism, microenvironment and specificity of the brain, a plethora of chemical, physiological and immunological compounds can contribute to such events. Among these compounds, we concentrated our interest on L-carnitine (L-Cn), which regulates the beta-oxidation of long chain fatty acids necessary for brain development, myelinization and growth. In contrast to fetal brain cells that grow easily in culture, adult brain cells show limited neurogenesis. Here, using adult brain cells from experimental mice, we show that although L-Cn does not improve their proliferative activity in short-term cultures, it accelerates the growth and differentiation of neurons, astrocytes, oligodendrocytes and ependymal cells from neurospheres in long-term cultures. Thus, the formation of a confluent neural network requires a 2-month period in culture. These observations provide new insights for in vivo use of L-Cn to support brain cell development in cases of injury or brain degenerative diseases.

L-carnitine modifies the humoral immune response in mice after in vitro or in vivo treatment

Although the role of L-carnitine (L-Cn) as a cofactor in the oxidation of long-chain fatty acids has been well established, this agent has also been recognized to have an important role in the regulation of carbohydrate metabolism, and consequently, the maintenance of cell membrane structure and cell viability. L-Cn has been reported to reduce the apoptotic levels of CD4+ and CD8+ cells. It has also been demonstrated to interfere with cells of the monocytic lineage by regulating their ability to produce growth factors that ultimately affect both T and B lymphocytic subsets. Therefore, in this study, we examined whether this agent affects the antigenic response of immune cells and determined the relative numbers of immune cells in the murine spleen after in vitro and in vivo treatment. The results showed that L-Cn reduces the relative numbers of CD8+, CD4+ and Ly5+ cells. This observation was consistent in all systems studied including (a) in vitro inoculation of antigen (DNP-HSA) and L-Cn, (b) in vitro priming of spleen cells treated with L-Cn in vivo, and (c) in vivo immunization and L-Cn administration. In all cases, the reduction of T lymphocytes correlated with the decreased production of interleukin-2. L-Cn, however, did not affect the production of specific antibody, which indicates that the observed reduction of Ly5-positive cells is due to cell differentiation of B cells to plasma cells.

Soluble ICAM-1 levels in the serum of endometriotic patients appear to be independent of medical treatment

Adhesion molecules regulate the interaction of cells with the extracellular matrix and/or other cells. The intercellular adhesion molecule-1 (ICAM-1; CD54) is a member of the immunoglobulin superfamily and expressed by several cell types, including leukocytes and endothelial cells. A circulating form of the usually membrane-bound molecule was identified and characterized in normal human serum and in sera from patients with endometriosis. In the present study, we established the serum-soluble ICAM-1 (sICAM-1) levels in patients with endometriosis. We also studied the effect of danazol and leuprorelin acetate depot on the levels of sICAM-1. Thirty-eight women, 18-45 years of age, with regular menses and documented pelvic endometriosis were recruited from a University Hospital setting. Twenty-two women with endometriosis were randomly divided into two groups. Danazol (600 mg) were given every day for 6 months, and 3.75 mg of leuprorelin acetate depot every 28 days for 6 months. Serum sICAM-1 concentrations were measured before, during and after treatment, and its quantitative determination was performed by an ELISA technique using a specific immunoassay. We found that (1) sICAM-1 levels were higher in women with endometriosis in comparison to healthy subjects; (2) the 6 month treatment with danazol or leuprorelin acetate depot increased sICAM-1 levels (P<0.001); (3) 3 months after termination of both treatments, sICAM-1 levels were unchanged. Although the mechanism leading to the increase of sICAM-1 needs to be further clarified, any benefits of medical treatment of endometriosis such as danazol or leuprorelin appear to be independent of changes in ICAM-1 serum levels.

Murine ectoplacental cone-derived trophoblast cells express chemokine receptors

Chemokine receptors (CCRs) have been shown to regulate T cell migration and differentiation as well as the establishment of Th1/Th2 bias. Furthermore, T cells and T cell products are essential to trophoblast development. Thus, postulating that chemokines as well as their receptors may be expressed by trophoblast to move T cells into an interaction with the feto-placental unit, we examined whether CCRs are expressed during the early stages of ectoplacental cone (EPC) formation. For this, murine EPC-derived trophoblast were examined for their ability to express CCRs constitutively or inducible by interferon-gamma (IFN-gamma). Immunofluorescence experiments on EPC-derived trophoblast cells showed that CCR3, CXCR4 and CCR5 are significantly expressed. IFN-gamma accelerated the mobilization of intracellular pools of CCR molecules during early cell culture periods (2-6 h) and, in most cases, increased their expression on EPC-derived trophoblast cells. CCR activity could be detected in the culture supernatants of these cells, inversely proportional to cell surface expression, suggesting the existence of rapid endocytosis and recycling mechanisms. This finding indicates that the level of intracellular CCRs may partly be determined in the extracellular matrix, an event that could play an important role towards neutralization of specific T cell/trophoblast interactions during early stages of pregnancy and protect the fetus against harmful maternal immune responses.

The possible anti-inflammatory role of circulating human leukocyte antigen levels in women with endometriosis after treatment with danazol and leuprorelin acetate depot

BACKGROUND

Endometriosis is defined as an inflammatory condition of the female reproductive tract, a state often associated with infertility and miscarriage. Many exogenously administered factors (treatments) control the disease via as yet unknown pathways. Possible candidate molecules involved in these mechanisms could be the serum-soluble human leukocyte antigens (sHIA) that have been detected in a variety of human body fluids and that are associated with several diseases.

AIMS

We here examine how danazol and leuprorelin acetate depot treatments exert their anti-inflammatory action. It is plausible that subtle alterations mediated by these treatments and in relation to sHLA may explain the pathophysiology of endometriosis and provide insights towards new therapeutic protocols.

METHODS

Indirect enzyme-linked immunosorbent assay (ELISA), using specific monoclonal antibodies, determined serum-soluble class-I and class-II HLA levels. ELISA readings from treated women were compared with normal healthy subjects.

RESULTS

Serum-soluble class-I and class-II HLA levels are statistically significantly lower (P < 0.001) in women with endometriosis than in the control groups. However, danazol but not leuprorelin acetate depot administration augments soluble HLA class I and class II (P < 0.01 and P < 0.001, respectively) to normal levels during the treatment period, an increase that may account for the anti-inflammatory effect and the remission observed.

CONCLUSIONS

It is shown that one of the underlying causes of endometriosis may be the lack of both circulating class-I and class-II antigen levels. Danazol administration acts via an induced release of these antigens, whose presence correlates with the degree of the inflammatory alleviation obtained. We thus provide evidence that the inflammatory state of the disease appears to be associated with soluble HLA levels because, 3 months after ceasing therapy, the circulating antigens in the serum return to the same levels that correspond to the pathological condition.

Embryonic immune development and risks of HIV infection

The importance of the maternal immune system, during both gestation and breastfeeding, for the health of future generations is discussed.

Nitric oxide production by pre-implantation embryos in response to embryotoxic factors

In this report, we examined whether nitric oxide (NO) is involved in early embryo death. We have chosen various experimentally defined embryotoxic stimuli in mice and determined their ability to induce NO production by 2-cell stage embryos. The embryotoxic factors used were interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), lipopolysaccharide (LPS), 5-Azacytidine (5-AzaC) and the murine embryotoxic antibody DF4. We showed that in all cases the embryotoxic stimuli induced NO production by early stage embryos that correlated with the induction of the inducible and/or endothelial isoforms of NO synthase. This study was also extended to the human system where sera from women who aborted were tested for their ability to act embryotoxically by inducing NO in early mouse embryos and mature murine placenta. The results obtained confirmed the embryotoxic character of NO found in these particular sera leading to the hypothesis that NO plays a potential role in early embryo death.

Interferon-gamma induces differentiation of ectoplacental cone cells to phenotypically distinct trophoblasts

Maturation of the murine ectoplacental cone results in the development of the placental tissue which essentially consists of two trophoblastic zones, the spongiotrophoblast and labyrinthine trophoblast. In this study we attempted to investigate the action of cytokines on ectoplacental cone cell differentiation to mature trophoblast cells. After determining the cellular composition of the ectoplacental cone cell suspensions based on the expression of cytokeratin, vimentin, Mac-1, class I and class II MHC antigens, the cells were exposed to the differentiation-inducing cytokines IL-3, GM-CSF, CSF-1 and IFN-gamma. From the four factors employed, only IFN-gamma increased the levels of cytokeratin-positive cells without inducing Mac-1 expression. IL-3 increased the percentages of cytokeratin as well as Mac-1- and vimentin-positive cells whereas GM-CSF and CSF-1 preferentially promoted an increase of the Mac-1 and vimentin markers. For further analysis, ectoplacental cone cells were negatively selected for Mac-1, class I and class II antigens to exclude non-trophoblastic contaminants and thereafter treated with the same cytokines. We show here that only IFN-gamma leads the sorted ectoplacental cone cells to a pure trophoblastic population composed of 100% cytokeratin-positive cells. The specificity of IFN-gamma on this differentiation pathway is strengthened by the fact that murine maternal serum on the day of EC formation contains high levels of this cytokine, suggesting that its natural presence supports - at least phenotypically - the in vivo differentiation of EC cells to trophoblasts.

IFN-gamma facilitates release of class II-loaded intracellular pools in trophoblast cells: a novel property independent of protein synthesis

Interferon-gamma (IFN-gamma) is an abortion-inducing factor, yet its effects in such a reaction are subject to various levels of regulation. The trophoblast cell line TROPHO-1 can be induced by IFN-gamma to express mRNA and surface class II major histocompatibility complex (MHC) proteins after 8 and 48 h of stimulation, respectively. Untreated cells, however, show an intracellular accumulation of class II antigens earlier (6 h), indicating the existence of MHC pools in the cystosol independent of any induction. On addition of IFN-y, immunofluorescence, subcellular fractionation, and ELISA experiments showed that class II antigen activity detected in the endosomal compartments of the cells could be measured in the culture supernatants. These soluble class II proteins, when isolated and purified using magnetic bead isolation techniques and tested in SDS-PAGE gel and Western blot experiments, had a molecular weight of 70 kDa. Administration of these molecules to pregnant mice as culture supernatants increased the abortion rate and decreased maternal hematocrit levels, effects that could be immunoabsorbed by anti-I-A(d) monoclonal antibodies (mAb). These results indicate that although surface class II molecules are not expressed on trophoblast cells, they accumulate in endosomal compartments and can be released from the cells on addition of IFN-gamma. This new IFN-gamma property, to mobilize intracellular pools of class II MHC antigens in trophoblast cells independent of de novo protein synthesis and induce their release to the extracellular matrix, is a mechanism that appears to be involved in the fetal rejection process, facilitating priming of the maternal organism against the fetal allograft.

Th1- and Th2-type lymphokine-assisted induction and release of chemokine receptors from primary human trophoblast cells

Chemokine receptors (CCRs) have been demonstrated to facilitate the entry of HIV in different cell types of infected individuals, including CD4(+) T cells and dendritic cells. The natural or inducible expression of CCRs on trophoblast cells could provide a valid mechanism for the in utero transmission of HIV from mother to fetus. Because of the rapid turnover of these receptors, we attempted to define the natural and inducible expression of surface CCR3 and CXCR4 on primary human trophoblasts during short periods of cell culture. In the absence of any external stimulus the expression of CCR3 and CXCR4 varied from 1% to 24%. Kinetic experiments show that the levels of both CCR3 and CXCR4 reach a peak of expression after 6 h of culture, whereas by 24 h they have almost disappeared. In the presence of IFN-gamma, CCR3 is showing an increasing pattern of expression after 4 h of incubation, reaching highest levels after 24 h of culture, whereas CXCR4 is kept at lower levels as compared with nontreated cells. Furthermore, in the presence of IL-4, CCR3 expression declines from 2 to 8 h of culture to increase again at 24 h, where 50% of the cell population is expressing the receptors. Under the IL-4 stimulus, CXCR4 shows a peak of expression at 8 h of culture. An interesting feature of this study is that we were able to detect soluble CCR activity in the culture supernatants of trophoblast cells, which followed an inverse pattern of this of surface expression. Thus, the inability of many laboratories to detect high levels of CCRs in placentae of HIV infected mothers may be due on these fast turnover of these receptors, which by the assaying time have either been released in the culture medium or been internalized to the cell.

Localization of pepstatin's inhibitory action during Fc-mediated antibody internalization: possible implications for antibody-mediated viral transmission

Antibody internalization via Fc receptors is an important cellular mechanism, possibly facilitating the entry of antigenic peptides or viral particles into cells when specific antibodies are present at the periphery. Using an experimental model of trophoblast cells, we have shown that anti-p21(ras) monoclonal antibodies can use IFN-gamma-induced surface Fcgamma receptors to enter the cell. This entry of anti-p21(ras) antibodies ultimately inhibits IFN-gamma-mediated class II antigen induction. Since there may be obvious and inevitable harmful aspects of this mechanism, during which Fc-mediated viral particle or autoantigen transport may occur, we concentrated efforts on defining a potent inhibitor able to eliminate such uptake. The results presented here show that the protease inhibitor pepstatin A efficiently inhibits Fcgamma receptor induction by IFN-gamma and also blocks the endocytic pathway followed by an antibody when it enters the cell at the level of early endosomal compartments. We thus postulate that the use of pepstatin A, because of its inhibition of autoantigen presentation or viral transmission, including that of HIV, may find important applications in therapeutic protocols.

Expression of corticotrophin-releasing hormone in the mouse uterus: participation in embryo implantation

The detection of corticotropin-releasing hormone (CRH) in the pregnant and non-pregnant uterus has driven research to determine the role of this 41 amino acid neuropeptide in the female reproductive system. As concentrations of CRH mRNA and its peptide product are greater in the implantation sites of the early pregnant uterus compared with the regions between implantation sites, CRH has been hypothesised to participate in blastocyst implantation. Using the mouse system as an experimental model, we studied the distribution of CRH in the uterus during the oestrus cycle and early gestational period, and now provide evidence for its involvement in embryo implantation using cell culture techniques. The percentage of CRH-positive uterine cells and the amount of CRH released during anoestrus, pro-oestrus and oestrus were determined by immunofluorescence and ELISA experiments respectively. The highest number of intracellularly CRH-positive cells was obtained during pro-oestrus, whereas the highest CRH concentration in uterine cell culture supernatants was detected during anoestrus. At early stages of gestation, CRH was detected in the endometrium on days 2, 3 and 4 of pregnancy and in the myometrium on days 3 and 4, whereas it was undetectable on day 5. The functional role of CRH during early gestation was evaluated by administering anti-CRH antibody to mice from day 3 to day 8 of pregnancy. This treatment resulted in implantation failure in 60% of the cases, in which implantation sites, although clearly present in the uterus, had failed to host an embryo. These results provide direct evidence about the involvement of CRH in murine embryo implantation and are in agreement with hypotheses postulated in humans.

Inhibition of nitric oxide production rescues LPS-induced fetal abortion in mice

In this report, we examined the involvement of the cytokines tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma, interleukin (IL)-4, and IL-10 as well as nitric oxide (NO) in the lipopolysaccharide (LPS)-induced experimental abortion model in BALB/c mice. Although in vivo administration of LPS in pregnant mice showed a 72% decrease of serum IL-10, no significant difference in serum TNF-alpha, IFN-gamma, and IL-4 levels, compared to controls, could be detected. At the same time, a correlation of fetal abortion and maternal splenomegaly with an important increase of NO synthesis in the serum was obtained. Simultaneous administration of LPS and aminoguanidine (AG; an inhibitor to NO synthase) rescued the LPS-induced fetal abortion, reduced maternal spleen weight to physiological levels, and decreased serum NO concentration to control levels. In vitro experiments showed that LPS directly induced NO production in primary placental cells and the TPOPHO-1 trophoblast cell line by stimulating the inducible isoform of NO synthase, which ultimately could be blocked by the NO synthase inhibitors AG and L-NAME. The results indicate that LPS, despite its beneficial involvement in intracellular infections, participates in inflammatory/autoimmune damage during pregnancy, leading to embryotoxicity, which is closely linked to the NO pathway.

Analysis of the endocytic pathway upon intracellular transport of IgG molecules through Fc receptors

The uniformly distributed Fc receptors (FcRs) on the surface of many cell types are involved in a variety of immune reactions by non-specifically facilitating the entry of antigen-specific IgG molecules to the cell. Such reactions may be beneficial to the organism when foreign antigens are involved, or harmful in cases of self antigens and viruses. In order to avoid the IgG-mediated self antigen presentation or viral infection in autoimmunity and viral attack respectively, we attempt in this study to inhibit the intracellular transport of antibodies. This blockage, however, implies: efficacy of inhibition, inability of de novo exocytosis of the internalised antibody and finally maintenance of normal cell growth and morphology. We thus concentrate our interest on the endocytic pathway followed by a neutralising antibody in murine trophoblast cells where we try to inhibit antibody intracellular transport by various agents according to the criteria set above. In our model-system, IFN-gamma, upon induction of FcRs, facilitates endocytosis of the anti-p21ras antibody which blocks in turn the IFN-gamma-induced surface class II major histocompatibility complex (MHC) expression. Using various intracellular transport inhibitors, we study the required conditions by which these compounds cancel the inhibitory action of anti-p21ras and allow induction of class II MHC molecules by IFN-gamma. The effectiveness of the inhibitors in a ranking order is shown as following: monodansyl cadaverine > didansyl cadaverine > pepstatin A > leupeptin > NH4Cl > brefeldin A > ZPCK > TPCK. From these inhibitors, only brefeldin A, leupeptin, pepstatin and ZPCK do not allow exocytosis of the antibody in the culture medium and only didansyl cadaverine, pepstatin and leupeptin maintain cell viability and morphology. However, by sequential elimination based on this study's established criteria, only pepstatin A and leupeptin are shown to be effective inhibitors to specific antibody intracellular transport, protecting also the cell's viability and physiology.

Uterine cytokine production during the menstrual cycle and preimplantation stages in mice

Female reproduction is the only system subjected to well defined periodic changes. The final stage of the menstrual cycle in mammals is the maturation of the ovum and the preparation of the female organism to support fetal development fertilization. Once pregnancy occurs, both maternal and fetal sites emit regulatory signals to ensure embryo development and maternal protection against a graft versus host (GvH) reaction initiated by the semi-allogeneic fetus. We and others have previously shown that each day of fetal development in mice is characterized by different cytokine production, detected not only at the proximity of the feto-placental unit (decidua, uterus), but also in maternal lymphoid organs (spleen), as well as in the serum. In the present study, we concentrated on the menstrual cycle and the preimplantation stages of pregnancy and defined the levels of GM-CSF, IL-10, IL-6, and IL-3 in the murine uterus during anoestrus, proestrus, oestrus, and second and third day of gestation. We show by immunofluorescence and ELISA techniques that GM-CSF is maintained at high levels during anoestrus, proestus, oestrus, and the second day of pregnancy while dropping on the third day. IL-3 levels are found elevated during proestrus, second and third day of gestation, IL-6 increases essentially during proestrus, whereas the production of IL-10 was detected during oestrus and the early stages of pregnancy. Immunoperoxidase staining on frozen sections of uteri during the early gestational period localize GM-CSF and IL-3 production in the endometrium, IL-10 in the endometrium on the second day of pregnancy, and endometrium/myometrium on the third day. Low levels of IL-6 could be detected in the endometrium/epithelium on the second day and endometrium/myometrium on the third day of gestation. The role of IL-3, IL-10, and, to a lesser degree, IL-6 is fortified by the embryo itself, since these cytokines were found to be produced by blastocysts as well. These results demonstrate the existence of a specific distribution of lymphokines within the uterine tissue, the role of which is being discussed.

The destructive action of IL-1alpha and IL-1beta in IDDM is a multistage process: evidence and confirmation by apoptotic studies, induction of intermediates and electron microscopy

Using the rat beta-cell RIN-5AH insulinoma line as a means for studying insulin-dependent diabetes mellitus (IDDM), it is shown that interleukin-1 (IL-1) induces beta-cell damage initiated by early apoptotic signals. This action is demonstrated by DNA fragmentation, as assessed by specific BrdU labeling, surface expression of Fas and nitric oxide (NO) production. In addition, the interplay between NO and Fas is shown, while scanning electron microscopy (SEM) confirms apoptosis by revealing the degree and type of cellular damage which, in the case of IL-1alpha, can be reversed by an inhibitor to NO synthesis. Apoptosis is also reconfirmed by transmission electron microscopy (TEM) by observing condensed nuclear chromatin after IL-1 exposure. Thus, treatment of insulinoma cells with IL-1alpha and IL-1beta seems to initiate a number of signals, including PKC activation as published previously, that ultimately lead to beta-cell destruction. Each IL-1 isoform, however, definitely follows a different pathway of action.

Serum levels of pro- and anti-inflammatory cytokines in non-pregnant women, during pregnancy, labour and abortion

Disturbance of the cytokine equilibrium has been accused for many pathological disorders. Microbial infections, autoimmune diseases, graft rejection have been correlated to over- or under-production of specific cytokines which are produced as responder molecules to the various immune stimuli. The sole naturally occurring immune reaction in the organism is developed during the gestational period where, despite the presence of a semi-allogeneic graft, maternal immunoreactivity is driven to support fetal growth. The successful embryo development has been attributed to the important intervention of cytokines where some have been characterized as indispensable and others deleterious to fetal growth. However, the physiological levels of many factors during the gestational process have not been determined. Thus, in the present study we have measured and established the values of IL-1alpha, IL-2, IL-3, IL-4, IL-6, IL-10, IL-12, GM-CSF, TNF-alpha and IFN-gamma during all phases of human pregnancy (first, second and third trimester of pregnancy, labour, abortions of the first trimester) as well as in the non-pregnant control state. This is an attempt to assess serum protein concentrations and present the physiological levels of these cytokines at certain time intervals providing thus a diagnostic advantage in pregnancy cases where the mother cannot immunologically support the fetus. Exploitation of this knowledge and further research may be useful for therapeutic interventions in the future.

Adsorptive or by pit formation endocytosis of immunoglobulins without loss of function as potential biotherapeutical application

We here describe an alternative way to microinjection by which cellular transport of immunoglobulins through surface membranes can be achieved after binding to specific surface receptors either induced or constutively present, or via Fc receptors (Ig-mediated). In this report, the internalisation of two antibodies in two different cellular systems is analysed: the anti-p21ras monoclonal antibody (MoAb) after surface Ig binding on murine placental cells and anti-cdc2 MoAb that binds directly to its surface receptor expressed on the human promyelocytic leukemia cell line HL-60. In both cases, binding and internalisation is followed by Electron Microscopy (EM) and function is assessed by different assays. The first involves abrogation of class II antigen expression induced by Interferon-gamma (IFN-gamma) and 5-Azacytidine (5-AzaC) known to be mediated by activation of the ras pathway. The second involves growth cessation of HL-60 cells after antibody adsorption when a G1-S-specific culture supernatant containing anti-cdc2 activity is employed, whereas no growth hindrance is observed when a G2-M-specific anti-cdc2 MoAb is used. Thus, the antibodies do not follow the lysosyme pathway and do not lose their functional activity. This method may be applied in the future in order to achieve biological or clinical therapies.

Production of embryotoxic IgG antibodies during IFN-gamma treatment of pregnant mice

PROBLEM

Administration of IFN-gamma during pregnancy in mice is deleterious not only to fetal survival but also to maternal physiology. Thus, injection of recombinant IFN-gamma from days 6-11 of gestation results in significant increase of fetal abortion, decrease of fetal weight accompanied by morphological defects of the embryo, and induction of class II MHC antigens on the spongiotrophoblast zone of the placenta. At the maternal level, this treatment causes splenomegaly, decrease of hematocrit levels, and increase of IgG production. In an attempt to dissect out the different phenomena observed, we examined the properties of polyclonal IgG antibodies contained in the animals' serum as to their ability to recognize antigenic determinants on IFN-gamma-induced placentae and isolated trophoblasts.

METHOD

Serum from IFN-gamma-treated pregnant mice was tested in vitro for its ability to recognize specific structures on primary trophoblasts and placental sections induced by IFN-gamma. In vivo this serum was injected in pregnant mice, and the outcome of pregnancy was evaluated. Monoclonal antibodies, resulting from the fusion of spleen cells from IFN-gamma-treated pregnant mice to a myeloma cell line, were used to certify the IgG-dependent embryotoxic effects observed with the polyclonal serum.

RESULTS

It was demonstrated that both the polyclonal serum and the monoclonal antibodies recognize antigenic determinants only on the IFN-gamma-induced trophoblasts, placentae, and embryos, reduce fetal size, and cause splenomegaly in the mother, but do not affect the percentage of abortions as compared to controls.

CONCLUSIONS

IFN-gamma-induces specific protein(s) on trophoblasts, which are responsible for embryotoxic antibody production in the mother. Since human abortion has been correlated with the production of embryotoxic IgG antibodies, this animal model may prove to be a useful tool in the analysis of events leading to pregnancy loss.

Placental tissue from human miscarriages expresses class II HLA-DR antigens

PROBLEM

Class II major histocompatibility antigens occupy a central role in the development of humoral or cellular immunologic responses. Surprisingly, in the maternal-fetal interphase, where two genetically different organisms come in direct contact, these antigens are absent. Based on previous studies in mice we have demonstrated that the absence of class II antigens represents another mechanism of fetal protection from the maternal immune response and, furthermore, that the induction of these antigens in the placenta makes the tissue immunogenic and susceptible to maternal immune attack, leading thus to fetal abortion. In order to test this hypothesis in humans, we analyzed the presence of class II antigens in aborted placentae.

METHOD

Class II expression on aborted placentae was examined by immunoperoxidase staining on frozen sections. We also studied hematologic changes that accompany such events, measuring white and red blood cell counts, hematocrit, hemoglobin, as well as IgG serum levels by standard techniques.

RESULTS

The detection of class II antigens on the aborted tissue indicates that these antigens are indeed major components of a pathway, which leads to a plethora of abnormal phenomena for the maternal organism such as low hematocrit levels, elevated IgG production, and increase of white blood cell numbers.

CONCLUSION

The results presented are consistent with our previous observations in mice and point to novel directions not only to pregnancy failure diagnosis, but also to new therapeutic approaches.

Specific nuclear binding of anti-cdc2 on p34cdc2 positive autonomously grown human leukemia cells induces differentiation

Intracellular p34cdc2 appears to be responsible for excessive cell growth. Therefore, disturbance of this cell cycle kinase by a specific monoclonal IgG1 anti-cdc2 antibody that specifically recognizes the product of the cdc2 gene, p34, was attempted. By using the surface p34 positive and rapidly proliferating HL-60 human promyelocytic leukemia cell line, transmission electron microscopy (TEM) and other standard techniques, it was found that the antibody, after an initial outer membrane attachment at 4 degrees C and entering the cells by raising the temperature to 37 degrees C, is directed and bound specifically on to the cell's nucleolus. This binding does not only demonstrate the intracellular localization of cdc2, but also appears to disturb its function. It thus induces a class II (HLA-DR) enhancement, increases the phagocytic ability of the cells and causes cellular elongation marked by a non-permanent adherence pattern. The results obtained are IgG independent and indicate that disturbance of constitutive cdc2 expression drives the cells to another level of maturation. The mechanisms behind these actions are still unknown. The results, however, may indicate that the regulatory pathways that govern the functioning of cell cycle stages are actively involved in the processes of cell differentiation. Similar findings have also been released where terminal murine erythro-differentiation may be achieved by manipulation of specific cell cycle kinases. On the contrary, normal already differentiated cdc2 negative human blood-derived monocytes remain insensitive to anti-cdc2 treatment, supporting the view that the presence of this kinase may be one of the reasons leading malignant cells to excessive growth, and that laboratory manipulation and reinfusion of these cells to leukemia patients may be a possible regimen for AML.

Effect of IFN-gamma administration in virgin and pregnant mice: distribution of lymphoid and myeloid cells in the spleen

Administration of Interferon-gamma (IFN gamma) is used in the therapeutic approach for mainly cancer treatment and viral infections in vivo. Recently we observed some important pathologic dysfunctions caused by IFN-gamma administration to pregnant mice. This treatment affected not only the growth and development of the feto-placental unit, but also, among other hematologic disorders, caused splenomegaly to the mother. In an effort to explain the observed hypersplenism, we have analysed the behaviour of macrophages, B and T lymphocytes in the spleen of virgin and pregnant mice after intraperitoneal administration of low IFN-gamma doses. Although the percentage of myeloid Mac-1 and F4/80 positive cells in spleen cell suspensions of virgin and pregnant mice do not change with the IFN-gamma treatment, immunoperoxidase staining of frozen spleen sections shows that in pregnant mice the monocytic cells accumulate at the central white pulp area of the organ, whereas in non-pregnant mice these cells are mainly found at the peripheral red pulp area. In contrast, the same treatment was shown to increase the numbers of Ly5 positive B cells in both virgin and pregnant mice, whereas B cells were found to form clusters only in the case of pregnant animals. We also show that IFN-gamma increases the numbers of Tcyt/sup (Ly2 positive cells) and TH (L3T4 positive cells) in the spleen of virgin mice but not in pregnant mice. Both populations display a physiologic distribution in the white pulp of the organ as assessed by immunoperoxidase staining of frozen spleen sections. Interestingly, the distribution pattern of IL-2- and IL-4-producing cells, which reflects the presence of Th1 and Th2 subpopulations was different in pregnant and virgin mice. Gestating females had IL-2 producing cells dispersed in the white pulp area, whereas IL-4 producing cells formed clusters mainly at the periphery of the organ. Virgin females had almost undetectable levels of IL-4 producing cells, whereas IL-2 producing cells were found at the periphery. Our results indicate that IFN-gamma alters the equilibrium between Th1 and Th2 cells, which in turn is responsible for the redistribution of myeloid and lymphoid cells in the spleen of pregnant mice thereby explaining the development of an active immune/inflammatory reaction.

Cytokine production in the serum and spleen of mice from day 6 to 14 of gestation: cytokines/placenta/spleen/serum

Pregnancy, like most biologic phenomena, involves the action of cytokines. These proteins have a short half-life and are believed to exert their effect close to their site of production, where diagnostic tests cannot be easily performed. Here we show that the cytokine content in the maternal serum reflects cytokine production and secretion from maternal spleen cells, which also correlates with production from decidual cells. We show that GM-CSF, IL-3, and IL-10 are present in the serum at specific time intervals during the first half of murine pregnancy, which correlates with their production from maternal spleen cells. Purified GM-CSF and IL-3 from spleen-cell-culture supernatants are biologically active molecules, able to stimulate placental-cell proliferation. Furthermore, TNF-alpha, which has been identified in many cases of fetal rejection as well as in labor, is shown to be naturally produced during the second half of pregnancy. Additionally, within the limits of the sensitivity of the technique we have used, the detection of IL-4 and the absence of detectable levels of IL-2 in the maternal serum strongly comforts the hypothesis that pregnancy is a Th2-dependent phenomenon. The results presented in this paper show that the cytokine profile during pregnancy can be monitored by simple blood tests, which may be of relevance both in the followup of a physiological human pregnancy and to the diagnosis of recurrent abortions due to cytokine imbalance.

Interferon-induced class II expression at the spongiotrophoblastic zone of the murine placenta is linked to fetal rejection and developmental abnormalities

Type II interferon is known to induce a plethora of gene expression involved in the humoral and cellular immunity. One of the multiple sites of action of gamma-IFN is the fetoplacental unit, where its role has not yet been clearly defined. We have previously shown in vitro that gamma-IFN may induce expression of class II MHC antigens on the spongiotrophoblast layer of the murine placenta, which under physiological conditions is negative for these antigens. Indeed, the absence of class II antigens from the placenta could be part of a mechanism evoked by fetal tissues to escape a host vs. graft reaction. In the present study we show that intraperitoneal in vivo administration of low doses of recombinant gamma-IFN to pregnant females specifically induces class II antigens on the spongiotrophoblast zone, increases fetal abortion, causes retardation of eye development in the fetuses and decreases fetal weight. This treatment also affects the maternal pathology as we witness a prominent hypersplenism in the mother accompanied by low levels of haematocrit, elevated IgG production and decreased granulocytic and thrombocytic counts. These results are specifically linked to the pregnant state of the mother, since virgin females do not develop any of the above abnormalities. Our results not only point to a new dimension in gamma-IFN's role during pregnancy, but may be of clinical importance for prophylaxis since administration of gamma-IFN to a pregnant female may lead to abortion, fetal abnormalities or cause haematologic disorders to the mother.

Placenta-specific growth factor production by splenic cells during pregnancy

Within the last 5 years strong evidence has correlated the successful outcome of pregnancy with various cytokines, which interfere with sperm mobility, fertilization, implantation, trophoblast outgrowth, as well as maternal immunoregulation. The newly arising antigens on the extra-embryonic membranes initiate many mechanisms protective to the fetus and not harmful to the mother, one of which is novel protein synthesis. These events are apparent in many different sites of the maternal organism including the decidual cap, uterine walls, draining lymph nodes, spleen etc. Working on a murine model, in the present study we concentrated on the growth factor production by spleen cells isolated from syngeneically pregnant mice on the 11th day of gestation. Focusing our interest on the proteins that have a stimulatory effect on placental cells, we fractionated 24 h spleen cell supernatants through a G-25 Sephadex followed by a Heparin-Sepharose affinity column and isolated pregnancy specific growth factors capable of inducing placental cell proliferation. In this study we focused on three growth factors, interleukin-3 (IL-3), granulocyte-macrophage colony stimulating factor (GM-CSF) and colony stimulating factor-1 (CSF-1), which have been previously shown to play an important role in placental growth. CSF-1 and IL-3 were detected in single Heparin-Sepharose fractions, whereas GM-CSF was found dispersed in essentially three fractions. Although we were able to detect these three growth factors in specific affinity column fractions, other proteins, which we have not yet characterized, showed significant biologic activity. Such biologic activity could not be detected from non-pregnant spleen cell supernatants similarly fractionated.(ABSTRACT TRUNCATED AT 250 WORDS)

Two novel colony-stimulating factor 1 (CSF-1) properties: it post-transcriptionally inhibits interferon-specific induction of class II antigens and reduces the risk of fetal abortion

Local production of 250 U/ml of Colony Stimulating Factor 1 (CSF-1) by decidual cells on the 11th day of murine pregnancy prompted us to investigate the role of this mononuclear phagocyte factor during gestation. We show that the presence of CSF-1 accounts for down-regulating induction of class II antigens on the placenta, antigens whose presence leads to fetal death. It is known from previous studies that gamma interferon (IFN-gamma) induces the expression of MHC-Ia antigens on the placenta causing thus fetal rejection due to an immune reaction the mother develops against the fetus. This Ia induction occurs both in vitro and in vivo, however, an extra dose of CSF-1, in addition to the physiological levels already present, overwhelms the ability of IFN-gamma to such induction and the embryos are rescued. Thus, CSF-1 appears to be an inhibitor of IFN-gamma induced class II expression, a property that may permit CSF-1 to be employed during gestation to safeguard the outcome of pregnancy and alleviate, by extrapolation to the human system, the recurrent abortion issue. This action, however, is not unique during gestation only. Other inducible IFN-gamma cells (WEHI-3, HL-60 and HeLa) are also blocked by CSF-1 not to express surface class II antigens, as it has been recently reported on glia cells. At the mRNA level, however, CSF-1 is unable to block class II induction, a finding that suggests a post-transcriptional regulation pattern.