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At least 379 records · Page 21Linked to original sources
PubMed1987

Histochemical evaluation of glycoconjugates in the male reproductive tract with lectin-horseradish peroxidase conjugates: II. Staining of ciliated cells, basal cells, flask cells, and clear cells in the mouse.

Efferent reproductive ducts of male mice, including ductuli efferentes, epididymis, and vas deferens, were fixed and embedded in paraffin, and sections were stained with a battery of lectin-horseradish peroxidase conjugates to localize specific sugars or sugar sequences in glycoconjugates. Cilia and the apical surfaces of ciliated cells in the ductuli efferentes stained intensely with lectin specific for sialic acid and terminal alpha-N-acetyl-D-galactosamine. Flask cells and clear cells in the epididymis reacted positively and similarly with most lectins used, providing evidence that these cell types are related. In contrast, disparities in lectin staining suggest that flask cells and clear cells are a cell type distinct from principal cells. Basal cells were not present in the ductuli efferentes but formed a continuous layer in the epididymis and vas deferens. Basal cells contained oligosaccharides terminated by sialic acid and alpha-D-galactose and varying amounts of terminal beta-D-galactose and alpha-N-acetyl-D-galactosamine. Basal cells also stained variably with lectins specific for the core region of complex type N-glycosidic side chains. The basal cells varied structurally, having long spinous apical processes approaching or reaching the lumen in region I of the epididymis and being low cuboidal or squamoid and lacking apical processes in epididymal regions II-V and in the vas deferens. The contiguous nature of the basal cells and the presence of glycoconjugates bearing terminal alpha-galactosyl residues in all basal cells suggest a possible role for these cells in a regulatory influence on transepithelial movement of fluid and/or ions in the epididymis and vas deferens.

Animals↗
PubMed1985

HTLV-I infection of T and B cells of a patient with adult T-cell leukemia-lymphoma (ATLL) and transmission of HTLV-I from B cells to normal T cells.

We analysed the DNA of different tissues of a patient (HS) with adult T-cell leukemia/lymphoma virus (HTLV-I). We detected viral sequences in fresh specimens from spleen, thymus, liver, skin and peripheral blood neoplastic lymphocytes. The pattern of HTLV-I integration is identical in the leukemic cells and in all other tissues analysed, but the signal intensity is strongest in the leukemic cells, indicating the source of HTLV-I proviral sequences was the leukemic T-cells which had infiltrated these tissues. In fact, the cultured skin fibroblasts of the patient did not contain HTLV-I sequence. However, cultured lymphocytes of this patient was consistently an immortalized B-cell line containing HTLV-I sequences in a manner indicative of a polyclonal infection. This cell line was also infected with the Epstein-Barr virus (EBV). In order to determine whether HTLV-I alone was sufficient for B-cell immortalization, we obtained single cell clones by limiting dilution. The DNA of all the cell clones that we analysed contained both the HTLV-I and EBV genomes, suggesting that immortalization of the B-cell was more likely due to the EBV rather than HTLV-I. Infectious HTLV-I viruses produced by the B-cell line still had the propensity to infect and transform T-lymphocytes in normal human umbilical cord blood. Unlike the parental B cells, the transformed T lymphocytes were clonally selected. Our results indicate that although the predominant infected cell population of the patient was his leukemic T lymphocytes, some of his EBV-positive B-lymphocytes were also polyclonally infected. The latter had a growth advantage in culture over the T lymphocytes but the virus produced by these immortalized B cells has not been adapted and has maintained its tropism for T cells.

B-Lymphocytes↗
PubMed2001

In vitro co-incubation of pig islet cells with xenogeneic human blood mononuclear cells causes loss of insulin release during perifusion: involvement of non-T-cell- and T-cell-mediated mechanisms.

Because the different steps of the human cellular immune rejection of pig islets are still poorly understood, our previous work concerned the intensity and mechanisms of the proliferation of human peripheral blood mononuclear cells (PBMC) to adult pig islet cells (PIC). As lymphocyte proliferation is not indicative of alteration of PIC, the present in vitro study evaluated cell-mediated immune effectors possibly involved in impairment of adult PIC. A test was thus developed, based on perifusion analysis of the alteration of insulin release from PIC incubated with different human cells. Compared to PIC incubation alone or with autologous pig splenocytes, seven-day co-incubation with whole human peripheral blood mononuclear cells (PBMC) (n = 18) led to almost complete abolition of basal and stimulated insulin releases (p < 0.0001). This effect could not be reversed by extensive sequential washes before perifusion of PIC, and the number of PIC was decreased by 78% after seven-day co-incubation with PBMC. PBMC are a complex mixture of cells involved in different xenogeneic mechanisms, and two components of this PIC impairment were then detected separately. First, the effect of PBMC against PIC was decreased (p < 0.0001) after removal of either MHC class II+ or CD14+ cells from PBMC. On the contrary, decreasing effect (p < 0.001) on insulin secretion was observed when only plastic-adherent or CD14+ cells were co-incubated with PIC. Additionally, alteration of insulin release from PIC cultured with PBMC or plastic-adherent cells was abolished dose-dependently (p < 0.0001 and p < 0.04, respectively) by gadolinium chloride (which inhibits macrophages), but not modified by cyclosporin A or mycophenolate mofetil which did not alter insulin release from PIC but blocked the proliferation of PBMC against PIC. A second mechanism was also detected, since co-incubation of PIC with purified human T cells remixed with antigen-presenting cells led to a decrease (p < 0.0001) of insulin release. This model based on the alteration of dynamic basal and stimulated insulin secretion provides detailed account of in vitro human cell-mediated impairment of PIC. It shows that the xenogeneic effect of whole mononuclear cells was strong and rapid. A crucial role was played by MHC class II+, CD14+, and plastic-adherent cells. Two mechanisms appear to be responsible for the role of these cells: 1) early direct effect, potentially involved in vivo in primary nonfunction of islets aggressed by monocytes/macrophages; and 2) the presentation of PIC xenoantigens leading to impairment by T lymphocytes, which may be involved in in vivo specific cellular rejection.

Animals↗
PubMed1998

CD34+AC133+ cells isolated from cord blood are highly enriched in long-term culture-initiating cells, NOD/SCID-repopulating cells and dendritic cell progenitors.

The AC133 antigen is a novel antigen selectively expressed on a subset of CD34+ cells in human fetal liver, bone marrow, and blood as demonstrated by flow cytometric analyses. In this study, we have further assessed the expression of AC133 on CD34+ cells in hemopoietic samples and found that there was a highly significant difference between normal bone marrow and cord blood versus aphereses (p <0.0001) but not between bone marrow and cord blood. Most of the clonogenic cells (67%) were contained in the CD34+AC133+ fraction. Compared with cultures of the CD34+AC133- cells, generation of progenitor cells in long-term culture on bone marrow stroma was consistently 10- to 100-fold higher in cultures initiated with CD34+AC133+ cells and was maintained for the 8-10 weeks of culture. Only the CD34+AC133+ cells were capable of repopulating NOD/SCID mice. Human cells were detectable as early as day 20, with increased levels (67%) apparent 40 days post-transplantation. Five thousand CD34+AC133+ cells engrafted about 20% of the mice, while no engraftment was observed in animals transplanted with up to 1.2 x 10(5) CD34+AC133- cells. The CD34+AC133+ population was also enriched (seven-fold) in dendritic cell precursors, and the dendritic cells generated were functionally active in a mixed lymphocyte reaction assay. AC133+ cells should be useful in the study of cellular and molecular mechanisms regulating primitive hemopoietic cells.

AC133 Antigen↗
PubMed1990

Functional human T cell-B cell hybridomas established from fusion of normal T cells and an EBV-transformed B cell line.

Human T cell-B cell hybridomas containing 92 chromosomes were derived by fusing normal stimulated CD-depleted T cells with the EBV-transformed human B cell line 729-HF. These hybridomas coexpressed the T cell surface markers CD3, CD8, and CD2 and the B cell surface antigens CD19, CD20, CD23, DR, and DQ. They weakly and variably expressed surface IgM and TCR. Genomic analysis revealed the presence of rearranged Ig genes as well as beta-T cell receptor genes that could be ascribed to the B and T cell parent, respectively. Analysis of TCR rearrangement suggests that the T-B hybridomas are, in fact, subclones of a single dominant clone. Although the hybrids expressed CD8 and not CD4, following preincubation with PWM, some the of clones induced IgG synthesis from normal B cells while the parent B cell line failed to demonstrate this activity. Stimulation of the hybridomas with PMA down-regulated the T cell lineage-specific antigen display (CD3, CD8, and TCR) and increased IgM production from the hybrids without changing B cell surface antigen display. These hybridomas may be useful to dissect the steps involved in the ultimate commitment of a cell to the B or T cell lineages and will be made available to interested investigators.

Antigens, CD↗
PubMed2000

Cultured human mast cells derived from umbilical cord blood cells in the presence of stem cell factor and interleukin-6 cannot be a model of human skin mast cells: fluorescence microscopic analysis of intracellular calcium ion mobilization.

To know whether cultured human mast cells raised from umbilical cord blood cells in the presence of stem cell factor (SCF) and interleukin-6 (IL-6) can be a model of human skin mast cells, the cells were stimulated, and intracellular calcium ion ([Ca(2+)](i)) mobilization was analyzed by fluorescence microscopic techniques in parallel with a measurement of histamine released from the cells. When IgE-sensitized mast cells were activated by anti-IgE, [Ca(2+)](i) elevation began at the periphery and subsequently proceeded toward the center of the cells. The increase in [Ca(2+)](i) in calcium ionophore A23187-stimulated mast cells began at the center and spread to the periphery of the cells. Significant histamine release was observed by each stimulation. However, either compound 48/80 or substance P failed to increase [Ca(2+)](i) with no appreciable histamine release. This study shows that there is heterogeneity of [Ca(2+)](i) mobilization in the activated human mast cells, and that cultured human mast cells derived from umbilical cord blood cells in the presence of SCF and IL-6 can not be a model of human skin mast cells.

Antibodies, Anti-Idiotypic↗
PubMed2000

Loss of cell-cell contact is induced by integrin-mediated cell-substratum adhesion in highly-motile and highly-metastatic hepatocellular carcinoma cells.

The cadherin-mediated cell-cell adhesion system plays a critical role in normal development and morphogenesis. Inactivation of this system is thought to be responsible for cancer invasion and metastasis. A human hepatocellular carcinoma (HCC) cell line, KYN-2, was observed to have great potential for intrahepatic metastasis when orthotopically implanted into the liver of SCID mice. In vitro cultures of KYN-2 cells showed that they formed trabecular structures in suspension but lost tight cell-cell adhesion and became scattered when attached to a substratum such as collagen or fibronectin. In response to adhesion to the substratum, subcellular colocalization of E-cadherin and actin filaments were shown to be reduced, and a significant amount of alpha-catenin was dissociated from the E-cadherin-catenin complex in KYN-2 cells. These changes of cell-cell adhesion were blocked by inhibitory monoclonal antibodies against beta1 and beta5 integrins. We found that c-Src was coimmunoprecipitated with E-cadherin-catenin complex and was tyrosine-dephosphorylated and activated in the adherent cells. The tyrosine dephosphorylation of c-Src was induced by cell adhesion to the substratum and inhibited by addition of inhibitory monoclonal antibodies against beta1 and beta5 integrins. These findings indicate that integrin-mediated cell-substratum adhesion inhibits cadherin-mediated cell-cell adhesion, possibly through c-Src activation, and suggest that this cross-talk mediates transient inactivation of the cadherin system and plays an important role in intrahepatic metastasis of human HCC. Modulation of this interaction might provide a new approach to prevent metastasis and recurrence of HCC.

CSK Tyrosine-Protein Kinase↗
PubMed2001

Increased levels of immune inhibitory CD34+ progenitor cells in the peripheral blood of patients with node positive head and neck squamous cell carcinomas and the ability of these CD34+ cells to differentiate into immune stimulatory dendritic cells.

OBJECTIVES: This study determined whether mobilization of immune inhibitory CD34+ cells by head and neck squamous cell carcinomas (HNSCC) is most prominent in patients who are node positive and whether these CD34+ cells could differentiate into immune stimulatory dendritic cells. STUDY DESIGN AND SETTING: Peripheral blood from patients with head and neck cancer was used to measure the frequency of CD34+ cells and their capacity to differentiate into immune stimulatory dendritic cells. RESULTS: This study demonstrated that increased CD34+ cell levels were most prominent in patients who were node positive and patients with recurrent disease. These CD34+ cells differentiated into dendritic cells that were able to present tetanus toxoid to autologous T-cells. CONCLUSIONS: Immune suppressive CD34+ cells that are prominent in patients with HNSCC who are node positive are able to develop into immune stimulatory dendritic cells. SIGNIFICANCE: Differentiation of tumor-mobilized CD34+ cells into dendritic cells may be an immunotherapeutic approach to stimulate antitumor reactivity.

Antigen Presentation↗
PubMed1991

Establishment of cell-to-cell contact by adoptively transferred adherent lymphokine-activated killer cells with metastatic murine melanoma cells.

A murine model of pulmonary B16 melanoma was used to study the infiltration into metastases of lymphokine-activated killer (LAK) cells and adherent lymphokine-activated killer (A-LAK) cells and, specifically, to study whether A-LAK cells are able to leave the tumor microcirculation and establish cell-to-cell contact with malignant cells. Fluorescence microscopy demonstrated that A-LAK cells accumulated in metastases twice as efficiently as LAK cells during interleukin-2 stimulation. Electron microscopy of pulmonary metastases 16 hours after administration of 2.5 x 10(7) A-LAK cells revealed A-LAK cells, identified by the presence of typical two-compartment granules, in direct contact with melanoma cells. This finding was confirmed by using A-LAK cells prelabeled with polycationized ferritin. In conclusion, our observations demonstrate unambiguously the ability of adoptively transferred A-LAK cells to establish contact with extravascular metastatic melanoma cells.

Animals↗
PubMed2006

Identification of novel gammadelta T-cell subsets following bacterial infection in the absence of Vgamma1+ T cells: homeostatic control of gammadelta T-cell responses to pathogen infection by Vgamma1+ T cells.

Although gammadelta T cells are a common feature of many pathogen-induced immune responses, the factors that influence, promote, or regulate the response of individual gammadelta T-cell subsets to infection is unknown. Here we show that in the absence of Vgamma1+ T cells, novel subsets of gammadelta T cells, expressing T-cell receptor (TCR)-Vgamma chains that normally define TCRgammadelta+ dendritic epidermal T cells (DETCs) (Vgamma5+), intestinal intraepithelial lymphocytes (iIELs) (Vgamma7+), and lymphocytes associated with the vaginal epithelia (Vgamma6+), are recruited to the spleen in response to bacterial infection in TCR-Vgamma1-/- mice. By comparison of phenotype and structure of TCR-Vgamma chains and/or -Vdelta chains expressed by these novel subsets with those of their epithelium-associated counterparts, the Vgamma6+ T cells elicited in infected Vgamma1-/- mice were shown to be identical to those found in the reproductive tract, from where they are presumably recruited in the absence of Vgamma1+ T cells. By contrast, Vgamma5+ and Vgamma7+ T cells found in infected Vgamma1-/- mice were distinct from Vgamma5+ DETCs and Vgamma7+ iIELs. Functional analyses of the novel gammadelta T-cell subsets identified for infected Vgamma1-/- mice showed that whereas the Vgamma5+ and Vgamma7+ subsets may compensate for the absence of Vgamma1+ T cells by producing similar cytokines, they do not possess cytocidal activity and they cannot replace the macrophage homeostasis function of Vgamma1+ T cells. Collectively, these findings identify novel subsets of gammadelta T cells, the recruitment and activity of which is under the control of Vgamma1+ T cells.

Amino Acid Sequence↗
PubMed2004

Human T cell activation by costimulatory signal-deficient allogeneic cells induces inducible costimulator-expressing anergic T cells with regulatory cell activity.

Although immunoregulation by several types of regulatory T cells is now clearly established in mice, the demonstration of such regulatory T cells in humans has been proven more difficult. In this study we demonstrate the induction of anergic regulatory T cells during an MLR performed in the presence of blocking mAb to the costimulatory molecules CD40, CD80, and CD86. Despite this costimulation blockade, which totally blocks T cell proliferation and cytokine production, a nonproliferating T cell subpopulation was activated to express inducible costimulator (ICOS). These ICOS(+) cells were anergic when restimulated with unmanipulated allogeneic stimulator cells at the level of proliferation and Th1 and Th2 cytokine production, but they did produce IL-10. These ICOS-expressing cells also blocked the capacity of reciprocal ICOS-negative cells to proliferate and to produce cytokines. ICOS(+) anergic cells could suppress allogenic responses of either primed or naive T cells through inhibition of IL-2 gene transcription. Suppression was not mediated by IL-10 and did not require ICOS-ICOS ligand interaction, but depended on cell-cell contact. Thus, a subtype of regulatory T cells in human blood can be activated in the absence of costimulatory signals from CD40, CD80, and CD86, and they can be identified by expression of ICOS after activation.

Adult↗
PubMed2000

Repertoire selection by pre-B-cell receptors and B-cell receptors, and genetic control of B-cell development from immature to mature B cells.

During B-cell development the surrogate light (SL) chain is selectively expressed in progenitor and precursor B cells during the developmental stages of D(H) to J(H) and V(H) to D(H)J(H) rearrangements. Approximately half of all muH chains produced by these rearrangements cannot pair with SL chains and cannot form a pre-B-cell receptor (pre-BCR). A spectrum of affinities between VpreB and individual V(H) domains generates preB cells with pre-BCR of different fitness which, in turn, determines the extent of the pre-B II-cell proliferation and the fidelity of allelic exclusion of the H chain locus. Once pre-BCR is expressed, SL chain expression is turned off. As pre-B II cells proliferate, SL is diluted out, thus limiting pre-BCR formation. As a consequence, pre-B II cells stop proliferating, become small and resting and begin to rearrange the L chain loci. Multiple rearrangements of the kappaL chain alleles are often detected in wild-type small pre-B II cells. Around 20% of the muH chain-expressing small pre-B II cells also express L chains but do not display the Ig on the surface. Hence, it is likely that not all L chains originally generated in resting pre-B II cells can pair with the muH chain previously present in that cell. The best fitting ones are selected preferentially to generate sIg+ B cells. Furthermore, the transition of immature B cells from the bone marrow to spleen and their development to mature cells appear as two separate steps controlled by different genes.

Alleles↗
PubMed2004

Membrane potential and endocytic activity control disintegration of cell-cell adhesion and cell fusion in vinculin-injected MDBK cells.

Cell fusion occurs during fertilization and in the formation of organs such as muscles, placenta, and bones. We have developed an experimental model for epithelial cell fusion which permits analysis of the processes during junction disintegration and formation of polykaryons (Palovuori and Eskelinen [2000] Eur. J. Cell. Biol. 79: 961-974). In the present work, we analyzed the process in detail. Cell fusion was achieved by microinjecting into the cytoplasm of kidney epithelial Madin-Darby bovine kidney (MDBK) cells TAMRA-tagged vinculin, which incorporated into lateral membranes, focal adhesions and nucleus, and, prior fusion, induced internalization of actin, cadherin and plakoglobin to small clusters in cytoplasm. Injected vinculin was still visible at lateral membranes after removal of junctional proteins indicating that it was tightly associated and perturbed the cell-cell contact sites resulting in membrane fragmentation. Injection of active Rac together with vinculin induced accumulation of cadherin to the membranes, but did not affect vinculin-membrane association. However, it hampered cell fusion probably by supporting adherens junctions. In order to stop endocytosis, we lowered intracellular pH of vinculin-injected cells to 5.5 with the aid of nigericin in KCl buffer. In acidified cells, injected vinculin delineated lateral membranes as thick layers, cadherin remained in situ, and cell fusion was completely inhibited. Since this treatment also leads to cell depolarization, we checked the vinculin incorporation in a KCl solution containing nigericin at neutral pH. In these circumstances, both endogenous and injected vinculin delineated lateral membranes as very thin discontinuous layers, but still fusion was hampered most likely due to perturbation in the initial vinculin-membrane association. We suggest that vinculin might function as a sensor of the environment triggering cell fusion during development in circumstances where membrane potential and local and transient pH gradients play a role.

Adherens Junctions↗
PubMed2003

Direct binding of cell polarity protein PAR-3 to cell-cell adhesion molecule nectin at neuroepithelial cells of developing mouse.

PAR-3 is a cell polarity protein that localizes at tight junctions (TJs) by direct binding to an immunoglobulin (Ig)-like cell-cell adhesion molecule JAM-1 in mammalian epithelial cells. Another Ig-like cell-cell adhesion molecule nectin plays a role in the localization of JAM-1 at TJs in epithelial cells. Nectin furthermore plays a role in the organization of adherens junctions (AJs) and TJs. Nectin comprises a family of four members, nectin-1, -2, -3, and -4. Nectins are associated with the actin cytoskeleton through afadin, of which the PDZ domain binds to nectins through their C-terminal four amino acids. We show here that PAR-3 binds to nectin-1 and -3 in neuroepithelial cells of the embryonic telencephalon, which are equipped with AJs, but not with typical TJs. Nectin-1, -2, -3, and afadin, but not JAM-1, were concentrated at AJs in neuroepithelial cells of the embryonic telencephalon at E13.5 and PAR-3 co-localized with nectins. PAR-3 was co-immunoprecipitated with nectin-1 and -3, but not with nectin-2 or JAM-1, from the mouse whole brain at E13.5. Recombinant PAR-3 stoichiometrically bound to recombinant nectin-1 and -3. The first one of the three PDZ domains of PAR-3 bound to the C-terminal four amino acids of nectin-1 and -3. The affinities of PAR-3 and afadin for nectin-1 and -3 were similar. Cadherin-deficient L cells expressing nectin-1 and -3 formed nectin-1- and -3-based cell-cell junctions, respectively, where PAR-3 as well as afadin was recruited. These results indicate that nectin-1 and -3 are involved in the localization of PAR-3 at AJs in the neuroepithelial cells of the embryonic telencephalon.

Adaptor Proteins, Signal Transducing↗
PubMed1993

Dominant negative mutation in cell surface beta 1,4-galactosyltransferase inhibits cell-cell and cell-matrix interactions.

In addition to its traditional location within the Golgi complex, beta 1,4-galactosyltransferase (GalTase) is also present on the cell surface, where it is thought to function as a cell adhesion molecule by binding to extracellular oligosaccharide ligands. Recent studies suggest that cells contain two forms of GalTase with distinct cytoplasmic domains. The longer form of GalTase contains a 13-amino acid cytoplasmic extension and is preferentially targeted to the plasma membrane, relative to the shorter GalTase protein that is confined primarily to the Golgi compartment. In this study, we created a dominant negative mutation that interferes with the function of cell surface GalTase by transfecting into cells cDNAs encoding truncated versions of the long form of GalTase containing the complete cytoplasmic and transmembrane domains, but devoid of the catalytic domain. In both F9 embryonal carcinoma cells and Swiss 3T3 fibroblasts, overexpressing the truncated long GalTase (TLGT) protein displaced the endogenous cell surface GalTase from its association with the cytoskeleton, resulting in a loss of intercellular adhesion and cell spreading specifically on matrices that use GalTase as a cell surface receptor. In contrast, overexpressing the analogous truncated short GalTase (TSGT) protein did not affect cell morphology or GalTase activity. In control assays, inducing the TLGT protein had no effect on cell interactions with fibronectin (which is independent of GalTase), or on the cytoskeleton attachment of another matrix receptor (beta 1 integrin), or on overall glycoprotein synthesis, thus eliminating nonspecific effects of the TLGT protein on cellular adhesion and metabolism. These results represent the first molecular manipulation of cell surface GalTase expression and confirm its function as a cell adhesion molecule. These studies further suggest that the cytoskeleton contains a defined, saturable number of binding sites for GalTase, which enables it to function as an adhesion molecule.

3T3 Cells↗
PubMed2006

Immune-privileged embryonic Swiss mouse STO and STO cell-derived progenitor cells: major histocompatibility complex and cell differentiation antigen expression patterns resemble those of human embryonic stem cell lines.

Embryonic mouse STO (S, SIM; T, 6-thioguanine resistant; O, ouabain resistant) and 3(8)21-enhanced green fluorescent protein (EGFP) cell lines exhibit long-term survival and hepatic progenitor cell behaviour after xenogeneic engraftment in non-immunosuppressed inbred rats, and were previously designated major histocompatibility complex (MHC) class I- and class II-negative lines. To determine the molecular basis for undetectable MHC determinants, the expression and haplotype of H-2K, H-2D, H-2L and I-A proteins were reassessed by reverse transcriptase-polymerase chain reaction (RT-PCR), cDNA sequencing, RNA hybridization, immunoblotting, quantitative RT-PCR (QPCR), immunocytochemistry and flow cytometry. To detect cell differentiation (CD) surface antigens characteristic of stem cells, apoptotic regulation or adaptive immunity that might facilitate progenitor cell status or immune privilege, flow cytometry was also used to screen untreated and cytokine [interferon (IFN)-gamma]-treated cultures. Despite prior PCR genotyping analyses suggestive of H-2q haplotypes in STO, 3(8)21-EGFP and parental 3(8)21 cells, all three lines expressed H-2K cDNA sequences identical to those of d-haplotype BALB/c mice, as well as constitutive and cytokine-inducible H-2K(d) determinants. In contrast, apart from H-2L(d[LOW]) display in 3(8)21 cells, H-2Dd, H-2Ld and I-Ad determinants were undetectable. All three lines expressed constitutive and cytokine-inducible CD34; however, except for inducible CD117([LOW]) expression in 3(8)21 cells, no expression of CD45, CD117, CD62L, CD80, CD86, CD90.1 or CD95L/CD178 was observed. Constitutive and cytokine-inducible CD95([LOW]) expression was detected in STO and 3(8)21 cells, but not in 3(8)21-EGFP cells. MHC (class I(+[LOW])/class II-) and CD (CD34+/CD80-/CD86-/CD95L-) expression patterns in STO and STO cell-derived progenitor cells resemble patterns reported for human embryonic stem cell lines. Whether these patterns reflect associations with mechanisms that are regulatory of immune privilege or functional tissue-specific plasticity is unknown.

Amino Acid Sequence↗
PubMed2001

Antigen presentation by liver cells controls intrahepatic T cell trapping, whereas bone marrow-derived cells preferentially promote intrahepatic T cell apoptosis.

Systemic activation and proliferation of CD8(+) T cells result in T cell accumulation in the liver, associated with T cell apoptosis and liver injury. However, the role of Ag and APC in such accumulation is not clear. Bone marrow chimeras were constructed to allow Ag presentation in all tissues or alternatively to restrict presentation to either bone marrow-derived or non-bone marrow-derived cells. OVA-specific CD8(+) T cells were introduced by adoptive transfer and then activated using peptide, which resulted in clonal expansion followed by deletion. Ag presentation by liver non-bone marrow-derived cells was responsible for most of the accumulation of activated CD8(+) T cells. In contrast, Ag presentation by bone marrow-derived cells resulted in less accumulation of T cells in the liver, but a higher frequency of apoptotic cells within the intrahepatic T cell population. In unmodified TCR-transgenic mice, Ag-induced T cell deletion and intrahepatic accumulation of CD8(+) T cells result in hepatocyte damage, with the release of aminotransaminases. Our experiments show that such liver injury may occur in the absence of Ag presentation by the hepatocytes themselves, arguing for an indirect mechanism of liver damage.

Animals↗
PubMed1995

Cytokines modulate in vitro invasiveness of renal cell carcinoma cells through action on the process of cell attachment to endothelial cells.

Cytokines play important roles in adhesion between various cells and endothelium. Cell-cell adhesion is also a critical step in the invasion of interstitial tissue by cancer cells. Using an in vitro invasion assay modified by cultured human umbilical venule endothelial cells (HUVEC) and an extracellular matrix (Matrigel) membrane system, we studied how cytokines affect the invasiveness of human renal cell carcinoma cells through action on the endothelium. When HUVEC were treated for 6 hours with tumor necrosis factor (TNF, 100 or 1000 U/ml.), interleukin-1 (IL-1, 10 ng./ml.) or IL-6 (1.0 or 10 ng./ml.), the treatment significantly increased in vitro invasiveness of the carcinoma cells. Enhancement of carcinoma cell invasiveness reflected the enhancement by the cytokine treatments of the ability of HUVEC to express vascular cell adhesion molecule-1 (VCAM-1). Application of anti-VCAM-1 monoclonal antibody (mAb) suppressed in vitro invasion of the carcinoma cells when HUVEC were treated with the cytokines at the above concentrations. Moreover, an adherence assay demonstrated that a larger number of carcinoma cells adhered to the endothelium treated by the cytokines than to endothelium not receiving such treatment and that anti-VCAM-1 mAb application inhibited the adhesion. The cytokine treatment of HUVEC did not affect type IV collagenolysis. These results indicated that cytokines can enhance the in vitro invasiveness of carcinoma cells through their action on endothelium (that is, augmentation of VCAM-1 expression) in the in vitro invasion assay modified with HUVEC-Matrigel-reconstituted membrane.

Antibodies, Monoclonal↗