engleski

Changes in the frequency of dendritic cell subsets in murin placenta

PROBLEM: Dendritic cells (DCs) represent a heterogeneous cell population in the cellular lineage and maturational stage. In both human and mice, different populations of DCs have been identified (myeloid and lymphoid derived). DCs are highly mobile cells and their sequential migration between tissues is accompanied by phenotypic and functional changes. Through the surface molecules and/or cytokines, they balance immune response towards immunity or tolerance. The role of DCs in pregnancy, where the mammalian fetus has been perceived, paradoxically, as a successful allograft, despite of expressing paternal transplant antigens, is still unclear, but they are thought to be involved in the regulatory functions. Thus, tolerance has been suggested to be ″ an active″ process, implying the critical role of DCs. This study analyzed presence, origin and state of maturation of DC subsets in murin placenta. METHODS: Investigations were performed on freshly isolated placental cells of adult (8-12 weeks) C57Bl/6 female mice, mated with syngenic (s) (C57Bl/6) and alogenic (a) (Balb/c) males (C57Bl/6xC57Bl/6 and C57Bl/6xBalb/c). The day of detection of a vaginal plug was designated as the day 1 of pregnancy. Pregnant mice were sacrificed on the 4, 7, 8 and 14 day of gestation (gd). Uteri were excised, cut into fine fragments, proceeded to enzymatic digestion (collagenase type IV) and single cell suspension was obtained. Phenotyping of CD11c positive (CD11c+) DCs was performed by flow cytometry analysis. Immunohistology was performed on the frozen tissue sections of day 7 and 14 pregnant uteri. We have also investigated the frequency of CD11c+ cells in the spleen of pregnant animals. RESULTS: CD11c+ cells, present in pregnant murin uteri, were identified by immunohistochemistry. In both syngenic and alogenic murin pregnancy model, the expression of CD11c was up regulated in the pregnant uteri (7 gd) (s=3.61%&plusmn ; ; 0.37SEM ; a=2.83%&plusmn ; ; 0.08SEM), compared to the virgin ones (1.53%&plusmn ; ; 0.09SEM). The expression of co-stimulatory (CD86) and MHC class II molecules (I-Ab) (s=31.50%&plusmn ; ; 4.63SEM ; a=23.25%&plusmn ; ; 0.75SEM ; virgin=6.89%&plusmn ; ; 1.89SEM) was also up regulated during the first trimester of pregnancy. Investigations have shown that murin DCs do not express CD8 molecule. CONCLUSIONS: Accumulation of CD8 negative dendritic cells (CD11c+CD8-) which express a high amount of co-stimulatory molecules in the first trimester murin placenta, suggests that they could play an important role in modifying the immune response during the post-implantation events. Supported by the Ministry of Science and Technology, Republic of Croatia (Grant No. 0062029).

Dendritic cells; Placenta; Pregnancy

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