Lectin histochemical studies of mouse granulated metrial gland cells

A lectin histochemical study has been carried out on mouse granulated metrial gland cells, the major leucocyte population that differentiates in the uterine wall in pregnancy. The binding characteristics of 26 lectins were examined using light microscopical methods. Fourteen of the lectins, with affinities ranging through N-acetylgalactosamine, galactose, N-acetylglucosamine, mannose and sialic acid residues, bound to the cytoplasmic granules of granulated metrial gland cells, and each appeared to bind to the limiting membrane of the granules. The binding characteristics of three of these lectins (Wheat germ agglutinin, Concanavalin A and Helix pomatia agglutinin) were examined using electron microscopical methods. These showed a different binding pattern to the cytoplasmic granules of granulated metrial gland cells compared with that found using light microscopical methods, as they appeared to bind evenly across the granule's matrix. This binding pattern corresponds to the reactivity of the granule matrix in the periodic acid--Schiff technique. Six lectins bound to the cell membranes of granulated metrial gland cells. These included the E and L isoforms of Phaseolus vulgaris agglutinin, with affinities for complex carbohydrates, whose binding differences were related to the stage of differentiation of the granulated metrial gland cells. The lectin binding described presents additional markers of granulated metrial gland cells and tools for investigating carbohydrate moieties in the functional activities of granulated metrial gland cells This revised version was published online in November 2006 with corrections to the Cover Date.     

Immunosuppressor activity of rat endometrial granulated cells and their differentiation

Natural killer and natural suppressor activities of the rat endometrial granulated cells were assayed on days 13 and 14 of pregnancy or pseudopregnancy. Metrial gland granulated cells were used as endometrial granulated cells. The natural killer activities of metrial gland granulated cells and other cells were determined by means of Hashimoto-Sudo test with K562 cells as targets. The estimation of natural killer activity included removal of the cells sticking to glass from a suspension of material gland granulated cells. Cytochemically, metrial gland granulated cells were identified by the presence of PAS-positive granules in the cytoplasm after treatment of the cells with diastase and identification of a specific antigen with the help of specific antisera. The natural killer activity of metrial gland granulated cells was twice weaker than that of splenocytes from the same pregnant or pseudopregnant females. The level of natural killer activity was proportional to the content of metrial gland granulated cells in a cell system. These data suggest that the natural killer activity of metrial gland granulated cells is realized via their contact with cell targets. Natural killer and suppressor activities were determined simultaneously for metrial gland granulated cells and splenocytes of the same rat with common cell targets. When estimating the natural suppressor activity of metrial gland granulated cells, the splenocytes of the same rat were used as an effector in a natural killer test. Various amounts of metrial gland granulated cells were added to the effector: target system at a ratio of 50 : 1. The natural suppressor activity of metrial gland granulated cells did not depend on the amount of metrial gland granulated cells present in a natural killer system. After fractionation in a Percoll gradient, the highest natural killer activity was recorded in a 60% Percoll fraction. The highest and lowest natural suppressor activities were recorded in 30% and 60% Percoll fractions, respectively. The culture medium was characterized by natural suppressor activity as well. The differences in mean areas of metrial gland granulated cells in 30 and 60% Percoll fractions between the pregnant (144.7 ± 13.4 and 75.0 ± 12.5 µm², respectively) and pseudopregnant (97.5 ± 4.9 and 69.2 ± 3.5 µm², respectively) females were reliable. The natural killer activity was estimated in all studied 23 samples of metrial gland granulated cells, among which 18 (79.6 ± 7.8%) displayed the natural suppressor activity as well. The absence of natural suppressor activity in five samples was combined with the absence of this activity in their culture medium and with a reduction in the mean area of metrial gland granulated cells in 30% Percoll fraction to 109 ± 5 µm². The data obtained confirm the known data on a low killer activity of metrial gland granulated cells and demonstrated for the first time the natural suppressor activity of these cells. It was concluded that the natural suppressor activity of metrial gland granulated cells is due to their differentiation from metrial gland granulated cells with natural killer activity.Translated from Ontogenez, Vol. 36, No. 1, 2005, pp. 26–34.Original Russian Text Copyright © 2005 by Podporina, Mikhailov.     

Fc receptors and human T lymphocytes in frozen-thawed peripheral blood cells

The present study was carried out to investigate the influence of cryopreservation on human T-cell subsets defined by their membrane receptors for Fc IgM (TM) and Fc IgG (TG) and by their membrane antigens. For this purpose isolated T cells, obtained by neuraminidase-treated sheep erythrocyte (E-N) rosetting, and enriched mononuclear cells were cryopreserved using a programmed freezing procedure. A significant decrease of the TM and TG cells was found whereas the proportion of T cells and their subsets determined by monoclonal antibodies seemed not to be influenced. The effectiveness of T-cell separation by E-N rosetting of frozen lymphocytes demonstrated no impairment of the E-receptor binding capacity of T cells. The PHA reactivity of separated T cells was maintained after cryopreservation; however, the spontaneous blastogenesis was reduced significantly. The selective loss of the TM and TG cells seemed to be dependent on the length of the phase transition time; over 90 sec the capacity of the expression of Fc receptors was profoundly affected. Neither an additional 20 hr incubation after hypotonic shock prior to cryopreservation nor incubation after thawing could repair this function of T cells. The data suggest irreversible damage of the Fc receptor expression capacity on the cell membrane as a result of a disturbance of metabolic pathways rather than a preferentially greater sensitivity of these cells to cryopreservation.     

Lectin histochemical studies of mouse granulated metrial gland cells

A lectin histochemical study has been carried out on mouse granulated metrial gland cells, the major leucocyte population that differentiates in the uterine wall in pregnancy. The binding characteristics of 26 lectins were examined using light microscopical methods. Fourteen of the lectins, with affinities ranging through N-acetylgalactosamine, galactose, N-acetylglucosamine, mannose and sialic acid residues, bound to the cytoplasmic granules of granulated metrial gland cells, and each appeared to bind to the limiting membrane of the granules. The binding characteristics of three of these lectins (Wheat germ agglutinin, Concanavalin A and Helix pomatia agglutinin) were examined using electron microscopical methods. These showed a different binding pattern to the cytoplasmic granules of granulated metrial gland cells compared with that found using light microscopical methods, as they appeared to bind evenly across the granule's matrix. This binding pattern corresponds to the reactivity of the granule matrix in the periodic acid--Schiff technique. Six lectins bound to the cell membranes of granulated metrial gland cells. These included the E and L isoforms of Phaseolus vulgaris agglutinin, with affinities for complex carbohydrates, whose binding differences were related to the stage of differentiation of the granulated metrial gland cells. The lectin binding described presents additional markers of granulated metrial gland cells and tools for investigating carbohydrate moieties in the functional activities of granulated metrial gland cells     

Antibody-dependent cellular cytotoxicity effector cells lack Ia antigens.

Surface immunoglobulin (sIg)-positive and sIg-negative subpopulations of macrophage-depleted murine splenic lymphocytes were obtained by Sephadex anti-Fab immunoabsorbent fractionation. These lymphocyte subpopulations were analyzed for the presence of Thy 1 and Ia alloantigens and also for Fc receptors by fluorescence microscopy. Concurrently, these lymphocyte subpopulations were studied for effector cell activity in antibody-dependent cellular cytotoxicity (ADCC). Effector cells mediating ADCC were contained in the sIg-negative lymphocyte subpopulation and sIg-positive lymphocytes did not mediate cytotoxicity. The majority of sIg-positive lymphocytes were found to bear Ia antigens and Fc receptors, and these cell surface structures were associated in that treatment of these cells with anti-Ia sera inhibited binding of complexed immunoglobulin to Fc receptors. In contrast, most sIg-negative, Thy 1-negative lymphocytes lacked Ia Antigens, and the Fc receptors detected on such cells were not blocked by anti-Ia sera. In addition, a small subpopulation of sIg-negative, Ia antigen-positive, Fc receptor-positive lymphocytes was found. Elimination of this subpopulation of Ia antigen-positive cells from sIg-negative lymphocytes, by treatment with anti-Ia serum and complement, did not diminish ADCC effector cell activity in the resultant cell population when compared with untreated sIg-negative lymphocytes. Thus, in murine spleen, nonphagocytic mononuclear cells that lack both sIg and Ia antigens were shown to mediate ADCC.     

Cells of the metrial gland: their relation to trophoblast cells and reproductive characteristics

Data on the origin, morphology and function of metrial gland cells are reviewed. Characteristic features of metrial gland cells are the availability of numerous eosinophilic granules lying near two round or oval nuclei and peripheral zone of the cytoplasm, generally devoid of organelles. This zone can generate pseudopodia-like projections. The notable peculiarity of metrial gland cells involves their ability to penetrate into blood vessels, to migrate towards the embryo, and to achieve the ectoplacental cone. The majority of metrial gland cells is accumulated in the decidua basalis zone where the tertiary trophoblast cells usually migrate. The metrial gland cells seem to constitute a cell population analogous to that of decidual cells. Data on the protective role of metrial gland cells are discussed. The metrial gland cells are proven to be polyploid. Polyploid nuclei are found both in mononucleate and binucleate cells. Acytokinetic mitosis is presumably a way leading to polyploidization of metrial gland cells.     

Immunosuppressor activity of rat endometrial granulated cells and their differentiation

Natural killer and natural suppressor activities of the rat endometrial granulated cells were assayed on day 13 of pregnancy or pseudopregnancy. Metrial gland granulated cells were used as endometrial granulated cells. The natural killer activities of metrial gland granulated cells and other cells were determined by means of Hashimoto-Sudo test with K562 cells as targets. The estimation of natural killer activity included removal of the cells sticking to glass from a suspension of material gland granulated cells. Cytochemically, metrial gland granulated cells were identified by the presence of PAS-positive granules in the cytoplasm after treatment of the cells with diastase and identification of a specific antigen with the help of specific antisera. The natural killer activity of metrial gland granulated cells was twice weaker than that of splenocytes from the same pregnant or pseudopregnant females. The level of natural killer activity was proportional to the content of metrial gland granulated cells in a cell system. These data suggest that the natural killer activity of metrial gland granulated cells is realized via their contact with cell targets. Natural killer and suppressor activities were determined simultaneously for metrial gland granulated cells and splenocytes of the same rat with common cell targets. When estimating the nuclear suppressor activity of metrial gland granulated cells, the splenocytes of the same rat were used as an effector in a natural killer test. Various amounts of metrial gland granulated cells were added to the effector : target system at a ratio of 50:1. The natural suppressor activity of metrial gland granulated cells did not depend on the amount of metrial gland granulated cells present in a natural killer system. After fractionation in a Percoll gradient, the highest natural killer activity was recorded in a 30% Percoll fraction. The highest and lowest natural suppressor activities were recorded in 30% and 60% Percoll fractions, respectively. The culture medium was characterized by natural suppressor activity as well. The differences in mean areas of metrial gland granulated cells in 30 and 60% Percoll fractions between the pregnant (144.7 +/- 13.4 and 75.0 +/- 12.5 microm2, respectively) and pseudopregnant (97.5 +/- 4.9 and 69.2 +/- 3.5 microm2) females were reliable. The natural killer activity was estimated in all studied 23 samples of metrial gland granulated cells, among which 18 (79.6 +/- 7.8%) displayed the natural suppressor activity as well. The absence of natural suppressor activity in five samples was combined with the absence of this activity in their culture medium and with a reduction in the mean area of metrial gland granulated cells in 30% Percoll fraction to 109.1 +/- 5.2 microm2. The data obtained confirm the known data on a low activity of metrial gland granulated cells and demonstrated for the first time the natural suppressor activity of these cells. It was concluded that the natural suppressor activity of metrial gland granulated cells is due to their differentiation from metrial gland granulated cells with natural killer activity.     

Countercurrent distribution of lymphocytes from human peripheral blood in an aqueous two-phase system. I. Separation into subsets of lymphocytes bearing distinctive markers

Lymphocytes from human peripheral blood have been separated by countercurrent distribution in a charged aqueous two-phase system composed of Dextran T 500 and polyethylene glycol 6000 with a cell yield of 59–88% and viability above 90%. A highly reproducible partition pattern was seen with four distinct peaks. Lymphocytes with surface membrane immunoglobulin (SmIg) were located in the first part of the distribution corresponding mainly to peak I. T lymphocytes as detected by E rosetting and α-naphthyl acetate esterase (ANAE) staining showed a broad distribution with a maximum in peaks II and III. ANAE-negative lymphocytes were seen in both extremes of the distribution, corresponding to B cells in the first part and to a population of E^? and SmIg^? lymphocytes in the last part. Monocytes were present in all fractions with some enrichment in peaks II–IV. Lymphocytes with low-affinity Fc receptors were found in B-cell-containing fractions in the first part of the distribution, but also in the last part. Lymphocytes with high-affinity Fc receptors were detected mainly in peak IV. It is thus demonstrated that peripheral blood lymphocytes can be fractionated into subpopulations enriched in cells with characteristic markers.     

An appraisal of Fc receptors on human peripheral blood B and L lymphocytes.

Human circulating lymphocytes with easily detectable surface immunoglobulin have been divided into two populations, B cells and L cells. This second population lacks membrane-incorporated Ig, but has a receptor for membrane-labile cytophilic IgG. In this study purified B and L lymphocytes were examined for Fc receptors that bind aggregated IgG and IgG complexed to erythrocytes. Purified lymphocyte populations were prepared by nylon columns and by negative selection with rosetting techniques. L lymphocytes bound aggregated guinea pig and human IgG, and formed rosettes with human erythrocytes sensitized with Ripley IgG (EA). Treatment of L lymphocytes with trypsin had no effect on the receptors for IgG. B lymphocytes did not bind EA and attachment of aggregated IgG was variable; up to one-third of these cells fixed aggregated human IgG to the cell membrane. Trypsin treatment abolished binding of Agg-IgG to B cells in sharp contrast to its effect on L cells. Furthermore, double-label immunofluorescence studies showed that cells with both membrane-incorporated Ig and receptors for aggregated guinea pig IgG were rare. These studies indicate that human peripheral blood B lymphocytes lack a high affinity, trypsin-resistant Fc receptor that is present on L lymphocytes.     

The structure and differentiation of granulated metrial gland cells of the pregnant mouse uterus

Summary A study was made with the light and electron microscopes of the granulated metrial gland cells of the decidua basalis of the pregnant mouse uterus, up to day 11 of pregnancy. The granulated metrial gland cells are large, up to 50 in diameter, mono- or binucleate and the glycogen rich cytoplasm typically contains many large glycoprotein granules which may be up to 5 in diameter. Morphological evidence is described in support of a lymphocyte-like cell being the precursor to the granulated metrial gland cell. This differentiation sequence is similar to that already proposed in the rat but differences between the ultrastructure of the mature metrial gland cells of rats and mice were noted.     

Measurement of natural killer activity and target cell binding by mouse metrial gland cells isolated by enzymic or mechanical methods

Cells of the metrial glands of mice were isolated by enzymic or mechanical dissociation procedures. Morphological observations indicated that up to half of the enzymically dissociated cells and nearly all of the mechanically dissociated cells were granulated metrial gland cells, but the presence of some fibroblast-like stromal cells among the latter population was not ruled out. Moreover, the granulated metrial gland cells had lost a substantial part of their granule content during isolation. Both cell preparations had little or no natural killer (NK) activity, indicating either that granulated metrial gland cells are not NK-like or that their NK activity was impaired by loss of granule-associated lytic substances or by other factors. Enzymically dissociated metrial gland cells did not bind significantly to the NK target cell YAC-1, nor did they develop granules, NK activity, or the ability to bind YAC-1 cells during culture in vitro, either in normal medium or with the addition of indomethacin or lymphokines. Mechanically dissociated metrial gland cells bound avidly to YAC-1 cells but not to P815 cells or adult thymus cells, which are not NK target cells. Since many if not most of the mechanically dissociated metrial gland cells appeared morphologically to be granulated metrial gland cells, their selective binding to an NK target cell suggests that granulated metrial gland cells may be related in some way to NK cells.     

Studies on the recognition of xenogeneic cells by nonimmune macrophages. I. Destruction of chicken fibroblasts in vitro by murine macrophages.

Human cord blood lymphocytes were compared with adult lymphocytes with regard to proportions of cells with surface markers for surface immunoglobulin (Ig), receptors for C′3 and the Fc-portion of IgG, as well as two types of erythrocyte rosettes (rapid and late E-rosettes). A significant decrease (P < 0.02 ? 0.05) in both early and late E-rosettes was noted when cord cells were compared to adult lymphocytes. After 20 hr of incubation at 37 °C, proportions of cells bearing Fc receptors in cord blood samples showed striking increments (P < 0.001) when compared with adult lymphocytes. T cell enrichment studies and sequential depletion of cells bearing Fc receptors as well as E-rosette forming cells indicated that the precursors of cells generating Fc receptors in vitro did not arise from cells with Fc receptors or T cell markers.     

A novel function of the herpes simplex virus type 1 Fc receptor: participation in bipolar bridging of antiviral immunoglobulin G

We describe a novel function of the Fc receptor of herpes simplex virus type 1 (HSV-1), its ability to participate in antibody bipolar bridging. This refers to the binding of a single immunoglobulin G (IgG) molecule by its Fab end to its antigenic target and by its Fc end to an Fc receptor (FcR). We demonstrate that various immune IgG antibodies, including polyclonal rabbit antibodies to HSV-1 glycoproteins gC1 and gD1 and monoclonal human antibody to gD1 blocked rosetting of IgG-coated erythrocytes at IgG concentrations 100- to 2,000-fold lower than required for rosette inhibition with nonimmune IgG. Steric hindrance did not account for the observed differences between immune and nonimmune IgG since rabbit anti-gC1 F(ab')2 fragments did not block rosetting. Murine anti-gC1 or anti-gD1 IgG, a species of IgG incapable of binding by its Fc end to the HSV-1 FcR, also did not block rosetting. When cells were infected with a gC1-deficient mutant, anti-gC1 IgG inhibited rosetting to the same extent as nonimmune IgG. This indicates that binding by the Fab end of the IgG molecule was required for maximum inhibition of rosetting. Bipolar bridging was shown to occur even when small concentrations of immune IgG were present in physiologic concentrations of nonimmune IgG. The biologic relevance of antibody bipolar bridging was evaluated by comparing antibody- and complement-dependent virus neutralization of an FcR-negative mutant and its parent HSV-1 strain. By engaging the Fc end of antiviral IgG, the parent strain resisted neutralization mediated by the classical complement pathway. These observations provide insight into the role of the HSV-1 FcR in pathogenesis and may help explain the function of FcR detected on other microorganisms.     

Methods for Studying Fc Receptor Expression

In the past two decades, rapid progress has been made in the field of Fc receptors. One of the reasons for this development has been the advances and improvements in the methodologies used to detect and analyze Fc receptors. This review describes the methods used to detect the murine and human Fc receptors of the various immunoglobulin isotypes at the RNA, protein, and functional level. We have given special attention to the binding assays used to detect Fc receptors through immunoglobulins or anti-Fc receptor monoclonal antibodies as probes. The various Fc receptor types exhibit a marked heterogeneity and we present a list of reagents that can differentiate between the different Fc receptor forms. These methods can detect Fc receptors on the cell membrane, as well as the cytoplasmic and secreted forms. Recent advances in the use of PCR and RNA/DNA analyses to study Fc receptor detection, expression, and function are also reviewed. The advantages and drawbacks of the various experimental approaches are presented. In addition, an appendix provides detailed protocols for the detection of Fc receptors by confocal immunofluorescence microscopy, rosetting, cytofluorometry, immunoprecipitation, and PCR     

Separation of human lymphocyte subpopulations by density gradient electrophoresis. I. Different mobilities of T (T mu, T alpha) and B lymphocytes from human tonsils

T and B lymphocytes from human tonsils were separated by density gradient electrophoresis on the basis of their surface charge. The high-mobility cell fractions were found to be highly enriched in T lymphocytes with only very small proportions of B cells. In contrast, the low-mobility fractions were predominantly B lymphocytes, and had only 10 to 30% contamination of T cells. The intermediate-mobility fractions contained both T and B lymphocytes in approximately equal proportions. IgM-bearing lymphocytes, as well as cells with receptors for mouse erythrocytes, the Fc portion of IgG, and complement were found in the intermediate- and low-mobility fractions. T lymphocytes, prepared by E rosetting, were also electrophoresed by this method and found to be of higher mobility as compared with peripheral blood T lymphocytes. T cells with Fc receptors for IgM (Tμ) or IgA (Tα) were found to be considerably heterodisperse with regard to surface charge and were present in all fractions. The separated cell fractions were treated in vitro with various concentrations of concanavalin A and thereafter examined for Tμ, Tγ, and Tα phenotypes. Low concentrations of Con A (2.5 μg/ml) had no effect on cell surface phenotypes. However, higher concentrations of Con A (20μg/ml) significantly reduced the numbers of T cells having IgM receptors (Tμ), but failed to alter the expression of the Tγ phenotype. The latter finding contrasts to that observed with T cells from the peripheral blood where high concentrations of Con A increase the proportions of the Tγ cells. This study demonstrates that density gradient electrophoresis can be used for the separation and study of lymphocyte subpopulations from human tonsils.     

Migration of granulated metrial gland cells from cultured explants of mouse metrial gland tissue

Summary The migration of granulated metrial gland (GMG) cells from cultured explants of metrial gland tissue obtained from mice killed between days 10 and 16 of pregnancy has been studied. GMG cells migrated from all of the explants but more GMG cells were found around explants obtained from mice at day 10 of pregnancy than around explants obtained at later stages of pregnancy. The number of GMG cells found around each explant reached a peak at days 1, 2 or 3 of culture but only a few GMG cells were found around the explants by day 7 of culture.     

The mononuclear cell in human blood which mediates antibody-dependent cellular cytotoxicity to virus-infected target cells. I. Identification of the population of effector cells.

Mononuclear cells (MC) from human blood were fractionated by a variety of physical and immunologic techniques, and the cellular subpopulations generated were assessed for their capacity to lyse herpes simplex virus (HSV)-infected target cells in the presence of IgG antibody to HSV. Latex phagocytosis and surface marker studies were performed in parallel in order to identify the major effector cells by their phagocytic properties and their possession of surface immunoglobulin and receptors for either sheep erythrocytes, C3, or the Fc fragment of IgG. Cytotoxic effector cell activity was unaffected or slightly enhanced after the removal of plastic-adherent or carbonyl iron-adherent MC, indicating that the major effector cell is not a classical monocyte. Similar results were obtained after removal of more than 90% of the T cells by depletion of rosette-forming cells. Likewise, effector cell activity was generally unchanged when more than 95% of the B cells were removed by filtering MC on nylon wool columns. Effector cell function was also found to be normal in three patients with B cell-deficient X-linked agammaglobulinemia. These observations strongly suggest that the effector cells are not T cells or B cells. A 4- to 5-fold enrichment in effector cells, however, was consistently found in a subpopulation, consisting of 5% of the unfractionated MC, that was dramatically enriched both for nonphagocytic cells with only Fc receptor (K cells) and for nonphagocytic cells with no detectable surface markers (null cells). Since, as is demonstrated in the accompanying report, effector surface Fc receptors play a critical role in the mediation of antibody-dependent cellular cytotoxicity directed at HSV-infected target cells, the major mononuclear effector cell in human blood is a K cell.     

Human monocytes, B lymphocytes, and non-B lymphocytes each have structurally unique Fc gamma receptors

Human Fc gamma-binding macromolecules were isolated from subpopulations of mononuclear cells by repetitive affinity chromatography. Mononuclear cells, nylon wool-filtered cells, plastic-nonadherent cells, and plastic-adherent cells from normal donors were radiolabeled by using 125I and lactoperoxidase. Washed cells were solubilized in 1% NP-40 buffer containing proteinase inhibitors at 0 degrees C. Fc gamma receptors were purified on human IgG-Sepharose columns by use of the repetitive affinity chromatography procedure. Analysis by SDS-polyacrylamide gel electrophoresis demonstrated only a 52,000 to 58,000 Mr Fc gamma receptor from nonadherent cell populations. Both rosetting and nonrosetting subpopulations of non-B lymphocytes expressed the 52,000 to 58,000 Mr receptor. The predominant Fc gamma receptor isolated from plastic-adherent cells was a 60,000 to 68,000 Mr macromolecule. Cell preparations enriched in B lymphocytes yielded prominent 43,000 Mr Fc gamma receptors. Thus human monocytes, B lymphocytes, and non-B lymphocytes each appear to have structurally distinct and unique Fc gamma receptors.     

The differentiation of the decidua and the distribution of metrial gland cells in the pregnant mouse uterus

Summary A study was made with the light microscope of the cellular changes involved in the formation of the decidua in the pregnant mouse uterus up to day 11 of pregnancy. The differentiation sequence was similar to that found by previous workers but the morphology and development of the basal zone is described in more detail. In addition, the morphology of glycogen rich cells in an area termed the lateral decidual zone is described. The distribution of granulated metrial gland cells and their precursors is described. These cells are first found in the uterine stroma before the blastocyst has implanted. Later they occur in the decidua and in the circular smooth muscle zone beneath the mesometrial triangle prior to the formation of the metrial gland. Granulated metrial gland cells are also found in the maternal blood spaces of the implantation site.     

Structure and expression of Fc gamma receptors on mouse suppressor T cell hybridomas

Antigen-specific and idiotype-specific mouse suppressor T cell hybridomas were analyzed for the presence and specificity of Fc gamma receptors (Fc gamma R) by EA rosetting and by flow microfluorometry with the use of monoclonal antibodies. We found that four hybridomas expressed Fc gamma R specific for IgG1 and IgG2b, one of which became Fc gamma R- during prolonged culture. Four other hybridomas and the fusion parent, BW5147, consistently lacked Fc gamma R. The 125I-labeled Fc gamma R were isolated from surface radioiodinated hybridoma cells solubilized with 1% Nonidet P-40, were purified by using single or repetitive chromatography on mouse IgG-Sepharose columns, and were analyzed by SDS-PAGE. An 125I-labeled 56,000 to 61,000 Mr macromolecule was isolated from each of the Fc gamma R+ hybridomas, but from none of the Fc gamma R- hybridomas nor from BW5147 cells. This macromolecule rebound to insolubilized mouse IgG1, IgG2b, and human Fc fragments, but not to insolubilized mouse IgG2a, IgG3, or IgA or human F(ab')2 fragments, consistent with the specificity observed for Fc gamma R on intact hybridoma cells. The mouse suppressor T cell Fc gamma R differs in size and specificity from mouse B cell Fc gamma R. A 70,000 Mr protein expressed on all hybridomas and on BW5147 cells was radiolabeled and, despite preclearing with ovalbumin-Sepharose, bound to the mouse IgG-Sepharose columns, presumably due to mouse antibodies to gp-70. This macromolecule was completely and specifically removed by using goat antiserum to gp-70.