Regeneration and tolerance factor of the human placenta induces IL-10 production.

Regeneration and tolerance factor (RTF) was originally identified in the placenta of mice and the isolated protein shown to have suppressive effects. In these studies, the gene cloned from thymus tissue was mapped to human chromosome 12. The role of recombinant RTF on cytokines was examined. In addition, we examined the human placenta by immunohistochemistry for RTF expression. RTF was expressed at the peripheral layer of cytotrophoblast in 7-9-week-old placentas. Using the RTF gene sequence, a recombinant protein was prepared and shown to induce IL-10 production. These data indicate that RTF is expressed by the tissues most intimately involved at the maternal-fetal interface, and its biological activity is capable of producing the necessary immune response for initiating and maintaining the maternal-fetal relationship.

Membrane phenotype and expression of perforin and serine esterases by CD3- peripheral blood and decidual granular lymphocyte-derived clones.

PROBLEM: Human first-trimester pregnancy decidua were found to contain large numbers of perforin (P)-containing cells, which varied in their membrane antigen phenotype. In this study results obtained by analyzing CD3- clones derived from human early pregnancy decidua and peripheral blood are reported. METHOD OF STUDY: Decidual tissue was obtained from vaginal termination of first trimester normal human pregnancies. CD3- clones were generated by limiting dilution cloning after the depletion of CD3+ lymphocytes. The cell membrane phenotype was determine by flow cytometry. Perforin was detected by fluorescence-activated cell sorter (FACS) analysis of permeabilised cells. Serine esterases (SE) were identified by histochemical staining for BLT-esterase. RESULTS: Cloned decidual cell populations retained the overall antigenic phenotype of freshly isolated decidual natural killer (NK)-like cells. All CD3- clones, either derived from decidua or from peripheral blood contained perforin. Serine esterases were present in every decidual clone analyzed. CONCLUSIONS: Limiting dilution cloning allows the clear-cut analysis of homogenous subsets of decidua-derived NK-like clones. The presence of large amounts of perforin in all of the CD3- clones underlines the extensive transcription of the perforin gene by NK-like lymphocytes.

Perforin-expressing lymphocytes in peripheral blood and decidua of human first-trimester pathological pregnancies.

PROBLEM: We have shown previously that the decidua of first-trimester human pregnancy is heavily infiltrated with perforin-positive cells. The aim was to detect expression of perforin in both decidual lymphocytes (DL) and peripheral blood lymphocytes (PBL) in the first trimester of pathological pregnancies: Anembryonic pregnancy and missed abortion. METHOD: Decidual tissue from a normal pregnancy group and from pathological pregnancies was obtained by vaginal curettage. Perforin (an intracellular antigen) and the cell surface antigens CD3, CD4, CD8, CD16, CD56, CD11c, and CD45RA were quantified simultaneously by flow cytometric analysis. RESULTS: In the missed abortion group, we found: 1) a relative decrease in the frequency of both CD4+P+ cells and CD56+P+ cells as well as the mean fluorescence intensity for perforin; 2) a relative increase of CD16+P+ PBL cells; and 3) a relative increase of CD4+ cells in PBL compared with anembryonic pregnancy and normal pregnancy. There was also a significant relative decrease in the proportion of CD4+ and CD8+ cells among perforin-positive PBL in both anembryonic pregnancy and missed abortion. CONCLUSION: Our results show that significant decreases in the prevalence of perforin-positive lymphoid cells, their subpopulations, and mean fluorescence intensity for perforin are associated with pregnancy failure.

Expression of functional molecules by human CD3- decidual granular leucocyte clones.

Cell surface and cytoplasmic antigen expression by 35 CD3- decidual granular leucocyte (DGL) clones, derived from human endometrial tissue in the first trimester of pregnancy, has been compared with both that of fresh CD3- decidual leucocytes and that of CD3- peripheral blood natural killer (PBNK) cell clones (n = 12). The majority of DGL clones retained the antigenic phenotype of fresh cells, although CD103 (HML-1) was expressed on 50% of DGL clones but only 17% of fresh DGL. Both cytoplasmic CD3 zeta and CD3 epsilon chains were detected in > 90% of DGL clones in the absence of cell surface CD3. Cytoplasmic CD3 zeta was present in almost all fresh CD3- DGL, whereas CD3 epsilon was not. Most DGL clones did not express surface Fc gamma receptors I-III (CD64, -32 and -16, respectively) and complement receptors (CR) types 1 and 2 (CD35 and 21, respectively), but 43% expressed CR3 (CD11b/18); in contrast, all PBNK clones were CR3+. The NK cell-associated molecules Kp43 (CD94) and the p58 molecule recognized by the HP3E4 monoclonal antibody were both present on a higher proportion of CD3- PBNK (91% and 50%, respectively) than DGL clones (31% and 14%, respectively), despite expression of CD94 by > 90% of fresh CD56+ decidual leucocytes. Five of 35 CD3- DGL clones expressed cytoplasmic CD3 zeta in the absence of expression of CD2, CD16 or the p58 molecule recognized by HP3E4. These variations between CD3- DGL and PBNK cell clones in expression of functional molecules may be related to previously reported differences in major histocompatibility complex-non-restricted cytotoxic activities between these two cell types.

Characteristics of perforin expressing lymphocytes within the first trimester decidua of human pregnancy.

PROBLEM: The number of perforin (P)-positive cells in decidua of pregnancy is larger than that observed in any other pathological condition. The aim was to investigate the distribution and the phenotype of P+ cells. METHOD: Decidual tissue was obtained from the first trimester vaginal termination of pregnancy. Tissue distribution of P+ cells was analyzed by immunohistochemistry. The method for simultaneous measurement of P and cell surface is presented. RESULTS: There is no difference in number and distribution of P+ cells between decidua basalis (DB) and decidua parietalis (DP). The percentage of P+ decidual lymphocytes (DL) is two times higher than in peripheral blood lymphocytes (PBL) (55% vs. 27%), and the prevalent phenotype is CD3- CD4- CD8- CD2+ (95%) CD11c+ (68%) and CD56+ (82%). CD56bright+ DL are also Pbright+ and this is the largest DL subpopulation (42.4% DL). Two different subpopulations of CD8+ DL exist: 1) CD8bright+, which are CD3+ CD56- P- and 2) CD8dim+, which are CD3- CD56+ P+. CONCLUSION: P expressing DL are prevalently nonclassical NK cells (CD16-) with low cytolytic activity but fully equipped with potent cytolytic machinery (Pbright+). There are no classical cytotoxic lymphocytes (CTL) (CD3+ CD8+ P+) in the decidua, and all CD8+ P+ cells are CD3- CD56+. The number of P+ cells is even higher in DP in the vicinity of noninvasive trophoblast, than in DB.

Decidual-trophoblast interactions: decidual lymphoid cell populations in basal and parietal decidua.

Immunohistochemical analysis of tissue specimens from human pregnancy decidua basalis in contact with invasive trophoblast of chorion frondosum and decidua parietalis in contact with non-invasive chorion laeve do not differ in the frequency of lymphoid cells of the following phenotypes (CD2, CD4, CD8, CD14, CD21 and gamma/delta TCR). A practical implication of this observation is that the collection of lymphoid cells from whole decidua by curettage for functional studies is justified.

Decidual-trophoblast interactions: decidual lymphoid cell function in normal, anembryonic, missed abortion and ectopic human pregnancy.

This study was designed to investigate the consequences of decidua-trophoblast interactions on the phenotype, spontaneous and induced proliferation and immunoregulatory potential of decidual leukocytes in normal pregnancies (NP), anembryonic pregnancies (AP), missed abortions (MA) and ectopic pregnancies (EP). Spontaneous proliferation of decidual non-adherent cells (NAD) from pregnancies with viable trophoblast inside the uterus is significantly higher than proliferation of peripheral blood lymphocytes (PBL) from the same groups (P < 0.001 for NP; P < 0.05 for AP). Spontaneous proliferation of decidual NAD cells from NP was higher (P < 0.001) when compared with AP and EP. The induced (PHA and Con A) responses of PBL from women with normal and pathological pregnancies were significantly higher than that of decidual NAD cells (P < 0.001). Higher proliferation of NAD decidual cells was obtained when Con A-stimulated NP were compared with MA and EP (P < 0.01). The interaction of viable trophoblast with intrauterine decidua appears to be a prerequisite for the activation of NAD suppressor cells, since NAD cells from MA produced stimulation instead of suppression, and NAD cells from EP had no suppressive effect. On the contrary, both NAD and adherent (AD) decidual leukocytes from NP and AP produced very strong suppression of PHA or alloantigen-induced PBL proliferation. The contact between trophoblast and AD decidual leukocytes is not necessary for their suppressive function, since even higher suppression is obtained with the cells from ectopic pregnancies.