An immunoregulatory role of decidua macrophages?

An immunoregulatory role of decidua macrophages?

Abstracts / Journal of Reproductive Immunology 71 (2006) 135–176 inhibit a Th1 profile. Finally, the B7-H1 receptor, PD-1, is expressed preferentiall...

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Abstracts / Journal of Reproductive Immunology 71 (2006) 135–176

inhibit a Th1 profile. Finally, the B7-H1 receptor, PD-1, is expressed preferentially on CD4+ and CD8+ lymphocytes that localize to the decidua as compared to those that are present in the peripheral circulation, suggesting that PD-1-expressing lymphocytes are either routed towards the placenta, or that PD-1 expression is induced on decidual lymphocytes. Given the known role of the B7-H1/PD-1 pathway in regulation of tolerance, autoimmunity, and tumor immunology, our results point to an important role for these proteins in regulation of the maternal immune response towards the fetus. Supported by grant R01HD045611. doi:10.1016/j.jri.2006.08.009 [K9] NK1/NK2/NK3/NKr1 paradigm in normal pregnancy and spontaneous abortion S. Saito a,b, , S. Myojo a , A. Nakashima a , A. Shiozaki a a

Toyama Medical and Pharmaceutical University, Japan; b 21st Century COE, Japan

Current dogma suggests that immunity is controlled by distinct type 1 (Th1) and type 2 (Th2) subpopulations of T cells discriminated on the basis of cytokine production. Recently, additional subtypes of T cells with immunosuppressive function, termed Th3 cells which produce TGF-␤, Tr1 cells which produce IL-10 and CD4+ CD25+ regulatory T (Treg), have been described. Recent data show that the NK1/NK2 paradigm can be also adapted in NK cells. NK cells can be classified as NK1 and NK2 type cells by their cytokine profile, similar to T cells. Our recent data have shown that the NK1/NK2/NK3/NKr1 paradigm can be adapted in peripheral and decidual NK cells. During pregnancy, peripheral blood NKr1 cells and decidual NK3 cells increased, while these NK cell populations significantly decreased in miscarriage cases, compared to those in normal pregnancy subjects. These data suggest that increased NK3 cells and decreased NK1 cells in the decidua play some important roles in the maintenance of pregnancy by regulation of maternal immune function at the feto-maternal interface. But there are no enough evidence that activated maternal immune cells attack the fetus or these cells could induce miscarriage in human. We studied the localization of granzyme B, granulysin and perforin which are expressed in activated NK cells and cytotoxic T cells. The numbers of granulysin positive cells in the decidua basalis of spontaneous abortion cases were significantly higher than that in the early normal pregnancy subjects. But there were no significant differences in

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perforin- and granzyme B- expressed cells between miscarriage cases and control subjects. The expression of granulysin was seen mainly in CD56bright NK cells by double immunostaining method and flow cytometry. We stumbled across a finding that the nucleus of extravillous trophoblast (EVT) cells were stained by granulysin in spontaneous abortion, and these cells were positively stained by TUNEL staining, anti-cleaved cytokeratin 18 staining and anti-cleaved caspase 3 staining suggesting that these cells were dying by apoptosis. Interestingly, EVT cells did not produce granulysin suggesting that granulysin-positive NK cells release granulysin into intracellular space and these intracellular granulysin are mobilized into the nucleus of EVT. To confirm this finding, the 9 kDa granulysin linked to GFP were expressed in EVT cells by the transfection method. Endogeneously expressed GFP-fused granulysin was preferentially localized in the nucleus and induced apoptotic cell death. These results suggest that granulysin in activated maternal NK cells could induce apoptotic cell death of EVT in human spontaneous abortion. Our data suggest that activated NK cells could attack the EVT, therefore, decreased NK1 cells and increased NK3 cells might inhibit the maternal NK cell-attack to the fetus in human. doi:10.1016/j.jri.2006.08.010 [K10] An immunoregulatory role of decidua macrophages? P. Sedlmayr Medical University of Graz, Austria Macrophages are present at high number at both sides of the feto-maternal interface (maternal decidua macrphages and fetal Hofbauer cells in the villous stroma). The former may be involved in modulation of the maternal immune response. The number of decidua macrophages increases after implantation in basal decidua. They are in close contact to the extravillous cytotrophoblast and Nitabuch fibrinoid, express the costimulatory molecule CD86, are positive for MHC II, are phagocytic, produce PGE2 which suppresses macrophage activation and inhibits T cell alloreactivity. They are controlled by progesteron which inhibits expression of iNOS. Classical activation via priming by IFN␥ and triggering by TNF␣ or LPS generates M1-type macrophages. These cells upregulate MHC II, produce proinflammatory cytokines (IL-1, IL-6, TNF), NO and respiratory burst. This leads to support of Th1-driven immune reactions such as killing of intracellular pathogens, tissue

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Abstracts / Journal of Reproductive Immunology 71 (2006) 135–176

damage, cellular immunity and delayed-type hypersensitivity. Classical activation is detrimental for pregnancy, as IFN␥ primes decidua macrophages for NOproduction in response to LPS, inducing early embryo loss in the mouse. However, the pattern of reeactivity of macrophages to various stimuli includes very different responses. IL-4 inhibits macrophages to express proinflammatory cytokines, but this is not mere deactivation as the macrophage mannose receptor (CD206) and MHC II is increased and endocytosis is enhanced, leading to the concept of alternative activation. The stimulating agents, IL4 and IL13, act via a partially identical receptor, eventually leading to suppression of Th1-mediated immune response (via IL-10), stimulation of Th2 and Tc2 responses, humoral immunity, allergic and antiparasitic reactions. The molecular repertoire of alternatively activated (M2) macrophages differs substantially from the classical one in terms of cytokines, chemokines and immune receptors. The terminology, however, is not uniform and so somewhat confusing: Whereas some authors restrict the term “alternative activation” to stimulation by IL-4 or IL-13, others include stimulation by IL-10 and glucocorticoids. Whereas there are some similarities, the latter agents rather lead to actual deactivation of macrophages, inducing downregulation of MHC-II, anti-inflammatory cytokines (IL-10, TGF␣) and production of PGE2 , eventually leading to immunosuppression. The phenotype of decidua macrophages is similar to M2 cells in a few respects: they express stabilin-1 and the macrophage mannose receptor. Further phenotypic and functional data need to be established in order to answer the question of the activation type of decidua macrophages. doi:10.1016/j.jri.2006.08.011 [K11] Interactions between HIV and STIs at a genital tract level R. Kaul University of Toronto and University Health Network, Canada HIV is generally transmitted from the genital secretions of an infected person, across the mucosal epithelium of their uninfected sexual partner. There is considerable evidence that sexually transmitted infections (STIs) independently increase both susceptibility to infection, and the level of HIV shedding. We have examined the impact of several STIs and their prevention on HIV transmission and subsequent host immune control.

HIV-specific cellular immune responses can be found in the blood and cervix of exposed, uninfected sex workers. These responses were transiently impaired by gonorrhea, which was strongly temporally associated with HIV acquisition. However, prevention of bacterial STIs through mass antibiotic treatment had no impact on HIV incidence. Chronic infection by Herpes simplex type 2 (HSV2) was associated with a 6-fold increase in HIV incidence, and with dramatic alterations in the genital mucosal immune milieu of both HIV-infected and uninfected women. In HIV-infected men, levels of HIV in semen correlated with local inflammation and with asymptomatic reactivation of CMV. Genital tract immune factors and the presence of common bacterial and viral co-infections have clear effects on HIV shedding, susceptibility and immune control. A greater understanding of these factors will be critical to the development of HIV vaccines, microbicides and immunotherapeutics. Acknowledgements Canadian Institutes of Health Research; Ontario HIV Treatment Network; Canada Research Chair Programme; Canadian Network for Vaccines and Immunotherapeutics (CANVAC); Rockefeller Foundation; National Institutes of Health; AIDS Research and Reference Reagent Program, NIH. doi:10.1016/j.jri.2006.08.012 [K12] Antiphospholipid antibodies and complement J.E. Salmon Cornell University, USA The antiphospholipid syndrome (APS), characterized by thrombosis and pregnancy loss that occur in the presence of antiphospholipid (aPL) antibodies, is a leading cause of miscarriage and maternal and fetal morbidity. Using a mouse model of APS induced by passive transfer of human aPL antibodies, we have shown that complement activation plays an essential and causative role in pregnancy loss and fetal growth restriction. Passive transfer of IgG from patients with aPL antibodies results in a 40% frequency of fetal resorption compared to <10% in mice treated with IgG from healthy individuals, and a 50% reduction in the average weight of surviving fetuses. In our initial studies, we found that inhibition of the complement cascade in vivo, using the C3 convertase inhibitor Crry-Ig, prevented fetal loss and growth restriction and that mice lacking complement C3 were resistant