Search

Decidual tissue, which includes typical (stromal type) decidual cells as well as infiltrating leukocytes, appears to play a local immunoregulatory role in the maintenance of pregnancy in nature. The present study evaluated the contribution of numerous leukocyte subsets characterized on the basis of morphology combined with cell surface markers to the development of murine decidua during syngeneic (CBA female X CBA male) and allogeneic (CBA female X C57BL/6 male) pregnancy. Collagenase dispersed decidua were subjected to total and differential counts and cell surface labeling for a radioautographic identification of various markers: S-IgM on B cells, Thy-1 on T cells, neither marker on null lymphocytes, Lyt- (1 or 2 or 1,2) antigens on T cell subsets, Mac-1 and I-A on macrophages, using 125I-labeled monoclonal antibodies or a sandwich labeling with 125I-protein A. The total cellularity of decidua basalis showed a biphasic rise in both pregnancies, with peaks on day 11 and days 15 and 16, but the allopregnant decidua showed a higher accumulation of all cell types indicating that an allogeneic conceptus causes an augmented deciduogenesis. The number of decidual cells, the most frequent cell class, rose to a peak on day 11 followed by a decline possibly due to cell death. The number of lymphocytes, the next frequent cell class, showed a parallel pattern initially, followed by a sharp secondary rise on day 16. This rise may be due to a withdrawal of progesterone, an antiinflammatory hormone. Null cells predominated amongst decidual lymphocytes (45-80%), as well as in the progestational endometrium (53%), indicating a hormonal control of their accumulation. The frequency of B cells was low (10-13%) and T cells (25-45%) comparable to that in the blood, with Lyt-1 only class being the most common T cell subset. Allopregnant decidua also showed a late rise in the total number of Lyt-2 only cells which may have a suppressor function. Macrophages, the next common leukocyte class, all expressed Mac-1. Their number rose to a plateau by day 12, but at a higher level in allopregnancy. I-A (needed for antigen presentation) was expressed by an increasing proportion (5-60%) of macrophages with advancing gestation. These findings provide a basis for further functional studies.

In previous studies we have shown that the ability of murine tumor cells to metastasize in situ is directly linked to expression of -GlcNAc beta 1-6Man alpha 1-6Man beta 1-branched complex-type Asn-linked oligosaccharides in tumor-cell glycoproteins. Here we demonstrate that cell-surface expression of beta 1-6 branched oligosaccharides in metastatic tumor cells is specifically associated with increased invasion of human amnion basement membranes in vitro. Compared to nonmetastatic SP1 murine mammary carcinoma cells, 2 metastatic sublines expressed higher levels of beta 1-6 branched oligosaccharides and were found to be invasive but poorly adhesive on the amnion basement membrane. Swainsonine, a non-toxic inhibitor of Asn-linked oligosaccharide processing which blocks the pathway prior to initiation of the beta 1-6 linked antenna, blocked metastatic tumor-cell invasion and increased adhesiveness. Swainsonine and the metalloprotease inhibitor O-phenanthroline inhibited invasion, apparently via independent mechanisms. O-phenanthroline did not affect tumor-cell adhesion to the amnion basement membrane and swainsonine did not block secretion of metalloproteases, beta-hexosaminadase or tissue plasminogen activator activity by the tumor cells. These results suggest that tumor-cell invasion of basement membranes requires both secretion of hydrolase activities and expression of beta 1-6 branched complex-type oligosaccharides at the tumor cell surface, such oligosaccharides being associated with reduced tumor-cell adhesion to extracellular matrix.

We have earlier shown that first trimester human decidual cells and decidual macrophages suppress T lymphocyte alloreactivity in an MHC-unrestricted manner by secreting PGE2, which blocks the generation of IL-2 receptors (IL-2R) and production of IL-2 by lymphocytes but does not interfere with the interaction between IL-2 and IL-2R or the lytic function of CTL, once generated. The present study examined whether these events constituted a physiological, immunoprotective mechanism in situ against the activation of maternal decidua-infiltrating leukocytes with potential anti-trophoblast cytocidal function. We examined (1) whether there was IL-2R expression, IL-2 production, or anti-trophoblast killer activity in short-term (0-3 day) cultures of collagenase-dispersed first trimester human decidua inclusive of leukocytes; (2) if not, whether any of these parameters could be stimulated in these cultures by blocking PGE2 synthesis with indomethacin, or neutralizing PGE2 with anti-PGE2 antibody; (3) whether exogenously added recombinant IL-2 in the presence or absence of indomethacin stimulated IL-2R expression or anti-trophoblast killer function in these cultures. IL-2R (as defined by Tac antigen) was measured in the whole cell population by a radioimmunoassay and further examined at the cellular level with radioautography. IL-2 production in culture supernatants was measured from the proliferative response (3HTdR uptake) of an IL-2-dependent (CTLL) cell line. Killer activity in fresh or cultured decidua-associated cells as well as PBL of normal or pregnant subjects was measured against 51Cr-labeled targets inclusive of autologous cytotrophoblast cells or long-term human trophoblast cell lines, K562 and Daudi cells. Results revealed a complete absence of IL-2R expression, IL-2 production, or anti-trophoblast killer activity in the untreated cultures of the decidua, but all these parameters were significantly stimulated in the presence of indomethacin or anti-PGE2 antibody. The indomethacin-stimulated killer cells had NK-like activity. Presence of high dose exogenous IL-2 alone in these cultures strongly stimulated IL-2R expression and anti-trophoblast killer function, which were augmented further in the additional presence of indomethacin. The resultant killer cells had LAK cell-like activity. These findings suggest that PGE2 secretion by first trimester human decidual cells blocks activation of maternal leukocytes in the decidua with potential anti-trophoblast killer function, by inhibiting IL-2 receptor generation and IL-2 production in situ.

We have studied the clonal heterogeneity of 2 spontaneously metastasizing mammary carcinomas which recently arose spontaneously in C3H/He female retired breeders. Cells of early (2nd to 5th) transplant generations of these tumors were cloned by a combination of semi-solid agarose colony formation and limiting dilution techniques. Growth characteristics of the various clones in vitro and their tumorigenicity in vivo were evaluated. Subsequently, the role of host immunity and of interclonal interactions in regulating growth of the different clones in vivo were analyzed. We found that, whereas all 16 clones isolated from one tumor (T-58) grew rapidly in vivo and in vitro, 10 clones isolated from the second tumor (MT-2) showed a wide disparity in their growth rates in vivo. Taken together, these clones could generally be divided into 3 categories: (1) rapidly growing lines which grew in vivo at rates similar to or higher than those of the parental line; (2) slow-growing lines which grew more slowly than the parental line; and (3) non-growers which failed to produce tumors in vivo with doses of up to 5 X 10(6) cells injected either s.c. or i.v. but grew in vitro at rates comparable to the parental line. No correlation could be established between the various growth potentials exhibited by these tumor lines and tumor cell morphology in vitro and in vivo, as determined by light and electron microscopy. Sublethal irradiation (550-650 R) of young animals prior to tumor inoculation, or before inoculation of tumor cells into old, low NK syngeneic mice, failed to modify the growth of slow-or non-growing lines in vivo, indicating that host cellular defense mechanisms against the clones, if existent, were not mediated by NK or radiosensitive B or T cells. When clonal interactions were studied by the simultaneous injection of different clones in vivo at different s.c. sites, we found that a slow-growing line failed to modify the growth rate of a rapidly growing line, but accelerated the growth of a second slow-growing line injected simultaneously on the contralateral side, and that this enhancement of tumor growth was radioresistant. A mixture of these 2 lines also grew more rapidly than the individual lines alone. Our findings suggest that phenotypic variations in tumorigenicity can be found in clonal lines derived from spontaneous primary tumors and that these variations are not related to cell cycle properties as measured in vitro.(ABSTRACT TRUNCATED AT 400 WORDS)

Mouse 3T3 cell lines capable of constitutively synthesizing an RNA complementary to the messenger RNA encoding TIMP, tissue inhibitor of metalloproteinases, were constructed by transfection with appropriate plasmid constructs. Many of the lines were down-modulated for TIMP messenger RNA levels and secreted less TIMP into the culture medium. In comparison to noninvasive, nontumorigenic controls, these cells not only were invasive in a human amnion invasion assay, but also were tumorigenic and metastatic in athymic mice. These results indicate that TIMP suppresses oncogenicity, at least in immortal murine 3T3 cells.

Our earlier studies revealed an increase in the level of null (surface IgM-negative, Thy 1-negative) lymphocytes in mice shortly after tumor transplantation and before the clinical appearance of spontaneous mammary tumors. The present study examined the splenic natural killer (NK) cell activity as well as the incidence of NK lineage cells in these hosts, since NK cells are considered to be a subset of null lymphocytes. Splenic NK activity against YAC-1 lymphoma targets was measured with a 4-hr 51Cr-release assay in CBA mice transplanted ip with 10(6) Ehrlich ascites tumor (EAT) cells, in elderly C3H mice prior to and during the growth of spontaneous mammary tumors (SMT) and in young C3H mice transplanted sc with 5 X 10(6) SMT cells or 10(6) cells from two syngeneic mammary tumor lines (T-58 and MT-2) of recent origin. In EAT-transplanted mice total NK activity in the spleen increased rapidly to a peak (11-fold) at 3 days, coincident with the null cell rise, but then declined to subnormal levels by Day 7 when the null cell level was still high. A similar pattern of activity was exhibited by intratumor lymphocytes isolated from the EAT. In SMT-transplanted mice splenic NK activity showed a small rise at Day 3, followed by a drop to below normal at Day 7, subnormal levels lasting for the tumor life span. Similar results were noted in T-58- or MT-2-transplanted mice. Null lymphocytes recovered during the peak NK activity from the spleen of 3-day EAT-bearing mice, when mixed with 10(6) EAT cells at 25:1 E:T ratio and adoptively transferred into fresh mice in a Winn type assay either ip or sc, completely prevented tumor development indicating a high enrichment of NK cells functionally effective in vivo. Elderly clinically tumor-free C3H mice showed measurable NK activity, which dropped after the appearance of spontaneous mammary tumors to very low levels, the magnitude of decline rising with increasing tumor age (1-11 weeks) or size. The incidence of NK lineage cells was measured from the tumor target (YAC-1 lymphoma)-binding ability of the splenic null cells, identified with a radioautographic technique. Null target-binding cells (TBC) were NK-1+ and included both active as well as inactive NK lineage cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Changes in small lymphocyte subsets in the lymphoid organs of young C3H mice were studied following i.m. injection of a carcinogenic dose of 3-methylcholanthrene in trioctanoin oil. Using monoclonal anti-Lyt antibodies and a sandwich radiolabeling method with 125I-labeled rabbit anti-mouse Immunoglobulin, the lymphocyte subpopulations in the thymus, spleen, and draining lymph node were examined by radioautography. During the fifth week following the administration of the carcinogen and prior to the appearance of histologically evident tumor cells, a sharp decrease in the level of Ly-1,2+ small lymphocyte population in the thymus was noted which coincided with a considerable increase (10-fold) in the Ly-2+ and a small increase (1.7-fold) in the Ly-1+ population. During the same period, a similar increase in the Ly-2+ population was also observed in the draining but not in the contralateral lymph node. The high levels of Ly-2+ cells lasted for more than 4 weeks in the thymus while, in the draining node, they lasted for 2 weeks and dropped to normal levels (0 to 2%) simultaneously with the appearance of tumor cells identified in histological preparations. Smaller increases (3-fold) in the Ly-2+ subset were also noted in the spleen and contralateral node, but they were seen later (7 to 8 weeks) and were shorter in duration. These systemic increases coincided with the appearance of macroscopic tumor nodules. The relative incidence of immunoglobulin+ cells did not change significantly in any of the organs tested during the entire tumor induction phase, while the level of null cells underwent a slight increase (approximately 2-fold) in all organs tested immediately prior to and following the appearance of macroscopic tumors. None of these changes was observed in trioctanoin oil-injected control animals. The mixed lymphocyte reaction response of the draining node cells, but not of the spleen, was suppressed during the period of increased level of Ly-2+ cells. Furthermore, during this period, s.c. transplantation of a syngeneic mammary tumor in the same leg resulted in enhanced local growth as well as metastatic spread of the tumor to the lungs in 3-methylcholanthrene-treated mice. These findings suggest that a localized immunosuppression associated with the rise in the Ly-2+ cells may be of functional significance during carcinogen-induced tumor development.

We have previously reported that natural killer (NK) lineage cells are progressively inactivated during tumor development by prostaglandin E2 (PGE2) secreted by host macrophages; that this facilitates spontaneous tumor metastases, which can be prevented by chronic indomethacin therapy (CIT); and that CIT combined with multiple rounds of interleukin 2 (IL-2) can cure experimental metastases and activate all killer lineage cells in situ including NK cells, lymphokine-activated killer (LAK) cells, and tumoricidal macrophages. The present study tested whether PGE2 secreted by tumor-bearing host macrophages exerts pansuppressor effects against the activation of T cells, NK cells, LAK cells, and tumoricidal macrophages from normal splenic cell populations. Macrophages isolated from CBA mice bearing 21-day intraperitoneal Ehrlich ascites tumors (EAT) or C3H/HeJ mice bearing 21-day subcutaneous T58 mammary adenocarcinomas were added (+/- 10(-5) M indomethacin, or a monoclonal anti-PGE2 ab) to syngeneic splenic lymphocytes to examine the effects on 1) polyclonal activation (3-d 3H-thymidine [3H-TdR] uptake) with concanavalin A (Con A); 2) one-way (CBA alpha BALB/C or C3H alpha BALBC) MLR (5-d 3H-TdR uptake) and subsequent CTL generation (tested against 51Cr-labeled Con A blasts of the stimulator phenotype); 3) NK activity (after 24-h co-culture) against YAC-1 targets; 4) generation of LAK cell activity (in the presence of 200 or 2,000 units recombinant IL-2 for 3 or 5 days), tested against NK-sensitive and NK-resistant targets. Similar effects were also noted on the generation of tumoricidal activity in normal splenic macrophages cultured for 3 days in the presence of LPS. Normal splenic macrophages added under the same conditions served as controls. Effects of pure PGE2 or PGF2 alpha (10(-6) M) were also examined on these activation events. Results revealed that tumor-host-derived macrophages (but not normal macrophages) markedly suppressed all these activation events and this suppression was abrogated nearly totally by indomethacin and totally by anti-PGE2 ab, indicating its mediation by PGE2. This finding ran parallel with high levels of PGE2 production by tumor-host-derived but not normal splenic macrophages. Pure PGE2 but not PGF2 alpha mimicked these suppressor effects. While tumoricidal activity was generated in normal macrophages in the presence of LPS, IL-2, or IFN-gamma or their various combinations (which led to further augmentation), these agents required the presence of indomethacin to generate significant killer activity in tumor-host-derived macrophages. macrophages.(ABSTRACT TRUNCATED AT 400 WORDS)

Decidual cells are direct descendants of endometrial stromal cells and the ultimate progeny of bone marrow-derived precursors. In view of their bone marrow genealogy and demonstrated immunoregulatory role during pregnancy, this study attempted to identify a lineage-specific differentiation marker(s) on murine decidual cells with the hope of tracing their developmental pathway and exploring their familial relationship to other lymphomyeloid cells. Two protein A-binding, IgG2b isotype monoclonal antibodies (secreted by clones 16F12 and 2G4F8) were raised by immunizing virgin CBA mice with syngeneic decidual cells. The presence and the density of the antigenic marker(s) recognized by these antibodies were examined by radioautography on various cell types in single cell suspensions of the decidua, placenta, and lymphomyeloid organs after a sandwich labeling with hybridoma supernatants followed by 125I-protein A. Both antibodies appeared to recognize antigen(s) unique for the decidual cell lineage in mice, humans, and rats. The incidence of antigen-bearing decidual cells increased with gestational age in CBA, C3H, and CD1 mice between days 8 and 14, and in humans between 6 and 10.5 wk; in rats, however, some decline was noted between days 8 and 14. The binding was always higher with 16F12 than with 2G4F8 supernatants. No significant binding of either antibody to trophoblast cells of the placenta or leukocytes within the decidua was noted in any of the above mouse strains or species. Little or no labeling of any cell type was seen on lymphomyeloid cells of the virgin or pregnant CBA mice, but a consistent labeling of a rare blast-type cell in the blood was observed with both antibodies, raising the possibility that this cell may represent the circulating precursor of the decidual cell lineage. It remains to be investigated whether these antibodies are recognizing the same or different differentiation antigen(s) on the decidual cells, and whether a conservation of this antigen(s) during speciation signifies its functional importance.

Three methods for producing semiallogeneic (F1----parental) hemopoietic chimeras with retained or regained fertility are detailed here. Prenatal (PN) chimeras were produced by injecting F1 ([BALB/c female x C3H/HeJ male] or [CBA/J female x C57BL/6 male]) fetal liver (days 13-18) or adult bone marrow cells (10(6)-10(7) cells/20 microliters/embryo) into the yolk-sac cavities of days 13-17 gestation BALB/c or CBA/J embryos, respectively, and allowing them to be born naturally. Neonatal (NN) chimeras were made by introducing F1 bone marrow cells (1-2 x 10(7) cells/0.25 ml) into newborn (less than 24 hr old) female mice through the anterior facial vein. Female mice were raised to maturity in both cases. Ovary-transplanted (OT) chimeras were made by first irradiating (9.5 Gy) and repopulating young female adult mice with 10(7) F1 bone marrow cells, followed by bilateral orthotopic transplantation of syngeneic ovarian tissue six weeks later. Females reconstituted with the above three methods were mated with normal syngeneic males and sacrificed at 11-16 days of pregnancy to evaluate hemopoietic chimerism. This was determined in all cases by a radioautographic evaluation of the extent of donor H-2 phenotype marker expression on splenic small lymphocytes, after an indirect labelling of single-cell suspensions with monospecific antibody and [125I]protein-A. Results indicate that hemopoietic chimerism was best in the PN group (0.3-78.1%, mean = 27.1); intermediate in the OT group (5.8-38.2%, mean = 18.1); and low in the NN group (0-14%, with one exception, which was 83.6%). Observed fertility was best for BALB/c host PN chimeras.(ABSTRACT TRUNCATED AT 250 WORDS)

Decidual cells are considered to be the endproduct of a hormonally induced transformation of endometrial stromal cells of the uterus. However, the source of these precursors remains unknown. This study of evaluated the possibility of their bone marrow origin by an examination of the H-2 phenotype of decidual cells in pseudopregnant bone marrow chimeras. These chimeras were produced by repopulating lethally irradiated CBA/J female (H-2k) mice with bone marrow from (CBA/J x C57BL/6J) F1 female (H-2kb) mice. Pseudopregnancy was produced with a hormonal regimen followed by an oil-induced decidual stimulus. Chimerism was evaluated radioautographically by an identification of the donor-specific Kb phenotype on cells with an immunolabeling technique with monospecific anti-H-2 serum followed by radioiodinated protein A. The extent of chimerism as indicated by the degree of Kb labeling on decidual cells as well as macrophages contained within the decidual nodules was quantitatively compared with that seen on splenic lymphocytes. Fair to good chimerism, as reflected by labeling for the donor-specific marker (Kb), was seen on splenic lymphocytes and macrophages within the decidual nodules in 6 out of 11 animals. A similar level of chimerism was detected on decidual cells in all but one of these six, in which case this was low. One animal showed low chimerism in the spleen but good chimerism on the decidual cells. The remaining four mice were nonchimeric for all three cell types. These results indicate that decidual cells and macrophages appearing within the decidual nodules of pseudopregnant mice are ultimate descendants of bone marrow cells.

Decidual cells are a distinctive cell population observed in the mammalian endometrium during pregnancy. Their appearance can also be induced with appropriate stimuli in the hormone-primed pseudopregnant uterus. This review deals with their life history, including the dynamic morphological events during the process of decidualization, cytochemical markers for decidual cell reaction, the surface markers and functions of decidual cells, and, finally, the origin and fate of this cell class. The recent discovery of the bone marrow origin of decidual cell precursors adds a new dimension to decidual cell biology. Future studies of steps in the differentiation of the decidual cell lineage await the identification of unique lineage-specific cell--surface of cytoplasmic marker(s); a precise knowledge of decidual cell functions can only be obtained from a discriminating analysis using purified cell populations.

Our earlier work revealed that PGE-mediated inactivation of NK cells in tumor-bearing mice by host macrophages promoted spontaneous lung metastasis that could be prevented or ameliorated by chronic indomethacin therapy. Since PGE was found to suppress the in vitro development and/or activation of a family of tumoricidal lymphocytes such as CTL, NK, and LAK cells by one or both of two mechanisms, that is to say, a down regulation of IL-2-R and an inhibition of IL-2 production, the present study tested whether a combined therapy with indomethacin and IL-2 was more effective than one with indomethacin or IL-2 alone in ameliorating established experimental lung metastasis. B6 mice injected intravenously with 10(6) highly metastatic B16F10 melanoma cells showed profuse micrometastases in the lungs by day 5, and macrometastases by day 10 which were confluent on day 21. Chronic indomethacin therapy by the oral route (14 micrograms/ml in drinking water) starting on day 0 or day 5, or a single round of IL-2 therapy (25,000 U rIL-2, every 8 h for 5 d on days 10-14) reduced the number of metastatic nodules by two-thirds (from a median of 473 in control mice receiving vehicles alone) by day 21. A single round of IL-2 as above, combined with either protocol of indomethacin therapy, completely or nearly completely irradicated the lung metastases, corroborated by a histological examination. An evaluation of splenic killer cell activity measured with a 4-h 51Cr-release assay against NK-sensitive YAC-1 lymphoma and B16F10 melanoma or NK-resistant thymic lymphoma 9705 targets revealed negligible activity in control tumor-bearing mice, and a good restoration of activity against NK-sensitive targets with either protocols of indomethacin therapy. IL-2 alone or a combination of IL-2 and indomethacin given by either protocol generated strong killer activity against all these targets, most marked with the combination therapy. Splenic killer cell phenotype in normal as well as all treated animals was ASGM1+, Thy-1-, and Lyt-2-. The combination therapy resulted in the strongest mononuclear cell infiltration in the lungs, with areas of young granulation tissue suggestive of repair sites of original metastases.

Hemopoietic status of the host is an important consideration in any cancer chemotherapy protocol. This paper examines several aspects of the response of the host lymphomyeloid system to tumors transplanted elsewhere: (a) characteristics of host leukocytes migrating into the tumor; (b) leukocyte dynamics in the marrow and the spleen; and (c) dynamics of hemopoietic stem cells. Repeated prelabeling of mice with 3HTdR prior to Ehrlich ascites tumor (EAT) transplantation indicated a large-scale, selective migration and/or retention of newly formed lymphocytes and monocytes within the tumor. Similar observations were also made in sc transplants of strain-specific TA-3(St) tumor. Bone marrow was found to be a major source of these mononuclear cells since their accumulation was suppressed by a prior irradiation of host marrow. Labeling with 125I-antimouse IgM, with or without prior incubation of cells with anti-theta serum, revealed that, within the 7-day-old EAT, about a third of the small lymphocytes were maturing B cells having readily detectable surface IgM, about a third were T cells expressing theta antigen, and the rest had neither marker, possible including very immature B cells. A high incidence of last cell category was also found in subcutaneous TA-3(St) tumors. Ip transplantation of 10(6) EAT cells into CBA/HT6 or TA-3(St) cells into A/J mice caused a transient decline in femoral marrow leukocyte level (affecting lymphocytes most) followed by a recovery and an overshoot. In contrast, there was a steady rise in splenic weight or cellularity mostly accountable for by lymphocytes. This was partly due to local lymphoid proliferation and partly due to extraneous migration. Parabiosis of CBA with T6 chromosome-bearing CBA/HT6 mice revealed that a large proportion of cells dividing in the spleen of the CBA host after tumor transplantation had migrated recently from blood. Using partial marrow chimeras (repopulated with T6 chromosome-bearing marrow cells), bone marrow was identified as their major source. Furthermore, host spleens showed an increased incidence of small lymphocytes bearing no detectable surface-IgM nor theta antigen (possibly inclusive of immature B cells), and a low incidence of T cells. Tumor transplantation produced a rapid and substantial decline in the pleuripotent stem cell (CFU-S) content of the femoral marrow followed by a recovery. The converse was true for the CFU content of the spleen, and in addition, there was an initial rise in the blood CFU level, suggesting an early CFU traffic from marrow to spleen. A qualitatively similar pattern was also noted for stem cells committed to granulocyte or macrophage development as evaluated from in vitro colony assays. An early rise in splenic CFU level was also elicited by injecting sonicated tumor cells or their plasma membrane fractions, thus possibly indicating an antigen-driven effect. A high level of colony-stimulating activity (for in vitro colony growth) was found in the tumor fluid...

Stromal type decidual cells recovered from the murine decidua by a mild collagenase dispersion procedure contain immunoregulatory cells whose ultimate precursors may originate from the bone marrow. To explore the familial relationship of these cells with other cells of the immune system, a battery of cell surface markers recognized on lymphomyeloid cells were examined and quantitated at the morphological level on typical stromal type decidual cells of the dispersed CBA mouse decidua at 8-14 days of syngeneic pregnancy, using a sensitive radioautographic technique. Cells were either labeled directly by exposure to 125I-labeled monoclonal antibodies against Thy-1, Mac-1, or Lyt antigens or indirectly by a sequential exposure to monoclonal anti-I-Ak (Ia.17) or monospecific anti-I-JK antibodies and 125I-labeled Protein A. Decidual cells were found to be Thy-1+/- (13-73% positive, the incidence rising with advancing gestation in the decidua basalis), Mac-1+/- (present of 6-11% on day 8 and 17-32% on day 12), I-A-, 1-J-, and Lyt-. Macrophages within the decidua were Thy-1-, Lyt-, Mac-1+, and I-A+/- (present on 5-61% of cells, the incidence rising with advancing gestation).(ABSTRACT TRUNCATED AT 250 WORDS)

The presence of H-2 antigens of the paternal and maternal haplotypes on mouse trophoblast cells was examined at several stages of pregnancy by using a sensitive immunolabeling technique followed by quantitative radioautography. Results revealed the presence of H-2 antigens (determined by the K or D loci) of both parental haplotypes on the F1 trophoblast cells. At 14-16 d of gestation, the antigen density was equivalent to that on adult thymocytes and there was a further 50% increase on day 18. H-2 antigens of both parental haplotypes are also found to be expressed on 11-13 d trophoblast cells.

Cysteine proteinases, particularly cathepsins B and L, have been strongly implicated in fostering metastasis in mice. In this work four different inhibitors of cysteine proteinases have been shown to inhibit the invasion of the human amnion by murine melanoma and mammary carcinoma cells in vitro. Two of the inhibitors are synthetic peptides [ZPhePheCHN2 (benzyloxycarbonyl-L-phenylalanyl-L-phenylalanyldiazomethane) and ZPheAlaCH2F [3-(N-benzyloxycarbonylphenylalanylamido)-DL-1-fluoro-2-butanone]] and two are thiol protease inhibitors (TPIn, TPId) isolated from the skeletal muscle of the hind limbs of normal and dystrophic mice, respectively. The inhibitors (ZPhePheCHN2, TPId), with apparent selectivity for cathepsin L, blocked invasion as effectively as inhibitors (ZPheAlaCH2F, TPIn) effective on both cathepsins. The data reveal that in these cell lines the cysteine proteinases contribute significantly to the invasive capacity of the cells, but to a lesser extent than do the metalloproteinases. We suggest that the cysteine proteinases facilitate the action of metalloproteinases (collagenase, gelatinase, and stromelysin), possibly by activating them, by inactivating the tissue inhibitor of metalloproteinases, and/or by making basement membrane matrix more accessible.

We have earlier shown that first trimester human decidual cells (typical decidual cells and decidual macrophages) suppress lymphocyte alloreactivity (MLR and CTL generation) in vitro in an MHC-unrestricted manner and that this suppression is mediated by PGE2. The present study explored the mechanisms underlying this suppression by noting the effects of decidual cells (+/- indomethacin or anti-PGE2 antibody) or chemically pure PGE2 on numerous T lymphocyte activation events following allogeneic stimulation in mixed lymphocyte culture (MLC) or polyclonal activation with Con A. The results revealed that this suppression was the net result of an action of PGE2 on at least two events during lymphocyte activation: (i) a down-regulation of IL-2 receptor development on lymphocytes, quantitated with a radioimmunoassay and radioautography; this was noted in MLC or Con A-stimulated lymphocyte cultures in the presence of decidual cells (reversible in the presence of indomethacin or anti-PGE2 antibody), or PGE2, but not PGF2 alpha; (ii) an inhibition of IL-2 production in the MLC, measured with a bioassay using an IL-2-dependent T cell line (CTLL-2) and a recombinant IL-2 standard. These effects blocked cell proliferation and eventual generation of killer cells in the MLC. Decidual cells or PGE2 did not interfere with IL-2-dependent proliferation of CTLL-2 cells, which require an interaction between IL-2 receptors on these cells and IL-2. Finally, neither agent interfered with the lytic function of CTL, once generated. These results indicate that the PGE2-mediated immunosuppressor function of early gestational human decidual cells is accomplished by an afferent blockade of the early events in T lymphocyte activation.

An immune system capable of discriminating between self and nonself evolved in nature long before the appearance of the viviparous mode of pregnancy, which brings maternal cells into a direct physical contact with genetically disparate cells of fetal origin. In the hemochorial type of placentation, the former include cells of the maternal immune system. This article briefly reviews the possible mechanisms that may protect the semiallogeneic conceptus in nature, with special reference to the role of the cells at the fetomaternal interface. We also present some new data on the antigenicity of pre- and postimplantation trophoblast cells and the immunobiology of decidual cells. Systemic changes in the maternal immune system appear to represent homeostatic responses to the presence of a semiallogeneic conceptus, unrelated to its protection; mechanisms for this protection must reside locally at the fetomaternal interface. We find that the lack of immunogenicity of the outer (trophoblast) cells of the preimplantation blastocyst can be explained by a transient disappearance of the major histocompatibility (MHC) antigens on their cell surface. However, following implantation and the formation of the placenta, class 1 MHC antigens reappear on certain classes of trophoblast cells, i.e., labyrinthine and spongiotrophoblast cells of the murine placenta. Similarly, cytotrophoblast cells of the early human placenta exhibit the presence of class 1 MHC antigens. An absence of class 2 MHC antigens despite the presence of class 1 antigens cannot entirely explain the lack of trophoblast immunogenicity. A local immunosuppression mediated by trophoblast cells themselves as well as maternal cells of hemopoietic origin in the decidua remain as a strong possibility. Typical decidual cells appear to play a central role in the maintenance of pregnancy because of their numerous functions: nutritive, endocrine, and immunoregulatory. Our studies reveal that they are descendants of bone-marrow-derived precursors, have unique surface markers recognizable with monoclonal antibodies nonreactive with other hemopoietic cell lineages, and have the ability to abrogate mixed lymphocyte reactions in vitro in a genetically unrestricted manner. Further studies directed at the cells of the fetomaternal interface should provide a better insight into the mode of survival of the nature's most commonplace allograft.