PubMed Health⌕ Search

Biomedical subjects

D Zarcone

Publications and source records attributed to D Zarcone.

At least 37 records · Page 2Linked to original sources
PubMed1992

Expression of adhesion molecules in lymphoproliferative disorders.

We review the role of adhesion molecule expression on malignant lymphoid cells as delineated by experimental studies and clinical observation. Adhesion molecules of the Ig superfamily, integrins, selectins, and the lymphocyte homing receptor CD44 mediate cell-to-cell and cell-to-extracellular matrix interactions. These molecules have been investigated with the aim (i) of defining certain biological features of the malignant cells, (ii) of providing a rationale to understand tumor organization, metastasis and organ specificity, and (iii) of detecting disease subsets and prognostic groups.

Animals↗
PubMed1991

Morphological features of cloned lymphocytes expressing gamma/delta T cell receptors.

We have analyzed the morphological characteristics of human T lymphocytes bearing CD3-associated T cell receptor (TcR) gamma and delta chains. BB3 and delta-TCS1 monoclonal antibodies (mAb) were used to identify two distinct, nonoverlapping populations of TcR gamma/delta + cells which express the products of V delta 2 and V delta 1 gene segments, respectively. In the peripheral blood, most V delta 1+ (delta TCS-1+) lymphocytes express the non-disulfide-linked form of receptor whereas V delta 2+ (BB3+) cells express the disulfide-linked form. The majority of cloned TcR gamma/delta + cells exhibit a growth pattern different from that of conventional TcR alpha/beta + cells as they adhere promptly to surfaces and undergo morphological changes which can be summarized as follows: cells spread on the surface, form a distinct uropod and, in the final phase of adherence, emit long filopodia ending with adhesion plaques. Immunofluorescence studies of TcR gamma/delta + clones demonstrated the presence of submembraneous actin microfilaments and actin-binding protein confirming that these cells are capable of active motility which is related to the propensity of TcR gamma/delta + cells to home to epithelia. Scanning electron microscope analyses of effector/target cell conjugates showed that in TcR gamma/delta + cells the region of the uropodia next to the cell body is responsible for the binding to tumor target cells. Interestingly, immunofluorescence analyses revealed that LFA-1 molecules are predominantly distributed in the uropodium whereas they are virtually absent in the cell bodies. These morphological characteristics of TcR gamma/delta + cells may pertain to defensive mechanisms the mucosal level.

Actinin↗
PubMed1991

X-linked codominant genes control all types of non-major histocompatibility complex-restricted cytotoxicity.

In most individuals, natural killer (NK) activity is abolished after lymphocyte irradiation with 3,000 cGy, while lymphocytes from a minority of males retain 100% NK activity and lymphocytes from some females retain 50% NK activity after this dose. Radiation sensitivity of NK activity is controlled by X-linked codominant genes. The frequency of the allele that imparts resistance is 7%. We studied a unique family in which both parents have the resistant allele such that the father is completely resistant and the mother is partially resistant. The three offspring of this couple were one sensitive male, one partially resistant female, and one completely resistant female. The radiation sensitivity of nonspecific cytotoxic functions mediated by various types of effector cells from all five family members were evaluated in order to determine whether other cytotoxic functions were controlled by the same set of genes. The cytotoxic functions investigated were: NK and lymphokine-activated killing, anomalous killing and lectin-dependent cellular cytotoxicity, and antibody-dependent cell-mediated cytotoxicity. Our data indicate that the radiation sensitivity of all types of nonspecific cytotoxic cells is under the same genetic control.

Adult↗
PubMed1991

Chronic active hepatitis B. Interferon-activated natural killer-like cells against a hepatoma cell line transfected with the hepatitis B virus nucleic acid.

In a rapid 51Cr release assay, peripheral blood mononuclear cells from 12 healthy donors did not lyse the hepatitis B virus deoxyribonucleic-acid-transfected human hepatoma cell line 2.2.15, but under the same experimental conditions they did lyse K562 cells. Peripheral blood mononuclear cells from 10 out of 16 patients with chronic active hepatitis B exhibited cytotoxic activity against 2.2.15 cells in the presence of a relatively reduced natural killer cell activity to the K562 cell target. Enhancement of the cytotoxic activity to 2.2.15 cells was statistically significant in the group of patients being treated with leukocyte alpha-interferon. The activity was not influenced by the degree of human leukocyte antigen type matching between effector and target, and was enhanced by depletion of T-cells and by in vitro interferon treatment. These results therefore support the concept of a natural killer-like cell activated by clinical administration of interferon in chronic active hepatitis B patients. This cell effector was lytic for the virus B negative HEP-G2 cells also. However, T-cells purified from a few patients failed to lyse the HEP-G2 while lysing the 2.2.15 target, thus indicating that a preferential recognition of the virus-infected target may be exerted by certain T-lymphocyte subsets. The use of the human leukocyte antigen type defined, highly differentiated, hepatitis B virus releasing 2.2.15 cell line as target for fresh lymphocytes in this cytolytic assay did not disclose cytolytic T-cells in an obvious way. Further manipulation of this system perhaps using T-cell clones may be the next step to exploit the investigative possibilities offered by the availability of the 2.2.15 cell target.

Adult↗
PubMed1990

[Neuralgic amyotrophy. A clinical and neurophysiologic longitudinal study of 3 cases].

The Authors describe three cases of neuralgic amyotrophy examined clinically and neurophysiologically at the onset of symptoms and after six months. At that time patients showed an objective improvement in strength and functions, though a few SEP and EMG alterations persisted. These findings are considered of out discrepancy between clinical and neurophysiological picture.

Adult↗
PubMed1989

Radiation sensitivity of resting and activated nonspecific cytotoxic cells of T lineage and NK lineage.

Natural killer (NK) cell-mediated killing of tumor cells is a radiation-sensitive function that in most subjects is completely abrogated by treatment of the effector cells with 3,000 cGy. The radiation sensitivity of LAK (lymphokine-activated killer) cells and their precursors, the bulk of which are NK cells, is undetermined. In this study, functional cytotoxicity assays and electron microscopy were used to determine the effect of radiation on the cytotoxic function of NK cells, LAK cells (generated by three-day culture of peripheral blood lymphocytes with IL-2), and LAK cell precursors (lymphocytes irradiated prior to culture with IL-2). For comparison, we analyzed the radiation sensitivity of lectin-dependent cell-mediated cytotoxicity (LDCC), which is primarily a function of CD3+ CD8+ granular lymphocytes. We also analyzed the radiation sensitivity of nonspecific cytotoxicity mediated by mitogen-activated T cells (AK activity). Following 3,000 cGy irradiation, NK cells retained their ability to bind to tumor cell targets but, as shown by both morphologic and functional analyses, they did not undergo activation after conjugate formation, and were unable to release the content of their granules. In order to evaluate LDCC, lymphocytes were depleted of CD16+ cells and tested in a cytotoxicity assay in the presence of Con A. The radiation sensitivity curve was comparable to that of NK cell-mediated cytotoxicity. IL-2-treated lymphocytes (LAK cells) were relatively radioresistant as compared with untreated NK cells, and their cytotoxic function was not abrogated until treatment with greater than 10,000 cGy. Cells receiving such radiation doses displayed cytoplasmic blebbing and damage of their cytoskeletal structures, with disruption of centrioles and microtubules, and disarray of the intermediate filaments. As was shown with NK cells, irradiated LAK cells formed conjugates with tumor targets but failed to degranulate. The radiation sensitivity of nonspecific cytotoxicity mediated by mitogen-activated T cells was identical to that of LAK effector cells. Doses up to 2,000 cGy did not prevent generation of LAK cells from blood lymphocytes, but 3,000 cGy did so. Blast transformation similar to that observed in IL-2-stimulated controls occurred when lymphocytes irradiated with 3,000 cGy were cultured with IL-2. These transformed cells were not cytotoxic and displayed a normal cytoskeletal apparatus but did not bear electron-dense granules.(ABSTRACT TRUNCATED AT 400 WORDS)

Cytotoxicity, Immunologic↗
PubMed1989

CD8+CD11b+ peripheral blood T lymphocytes contain lymphokine-activated killer cell precursors.

CD3+CD8+ cells, purified from peripheral blood T cells by depletion of CD4+ lymphocytes, were tested for their cytotoxic activity against K-562 or HL-60 cells. Freshly prepared cells had no cytotoxic function, but upon exposure to recombinant interleukin 2 (rIL2) in vitro they acquired a lymphokine-activated killer (LAK) activity. Fractionation of CD3+CD8+ cells into CD11b+ and CD11b- cells demonstrated that all the cells with the potential of developing LAK cell functions were within the CD8+CD11b+ subset. These cells lacked natural killer cell markers such as CD16 or NKH1, but a proportion of them stained for Leu-7. Furthermore, they expressed the alpha/beta chains, but not the gamma/delta chains, of the T cell receptor, as could be determined by staining with the appropriate monoclonal antibodies. CD8+CD11b+ cells had a large granular lymphocyte morphology, as shown by both cytochemical and electron microscopy analyses. They proliferated in response to IL2 in vitro and developed cytotoxic functions against a number of natural killer resistant targets. Their response to phytohemagglutinin or pokeweed mitogen was very weak or absent. By contrast, CD8+CD11b- cells failed to generate LAK cells in response to rIL2, did not show a large granular lymphocyte morphology, but responded vigorously to phytohemagglutinin or pokeweed mitogen. Purified CD8+CD11b+ cells were cloned by limiting dilution in the presence of rIL2. The observed cloning efficiency of 19 +/- 0.3% indicates that a fraction of the cells only could respond to IL2. Furthermore, only 50% of the clones obtained had a LAK cell function. These data show that CD8+CD11b+ cells represent a heterogeneous cell population. Nevertheless this cell subset probably represents the major source of LAK cell progenitors within the circulating T cells.

Acid Phosphatase↗
PubMed1989

Morphologic and functional characterization of human peripheral blood T cells expressing the T cell receptor gamma/delta.

The morphologic and functional characteristics of cells freshly isolated from human peripheral blood and bearing a T cell receptor (TcR) gamma/delta were analyzed. Cell preparations highly enriched for TcR gamma/delta+ cells were obtained by treatment of E rosette-forming lymphocytes with anti-CD4 and anti-CD8 monoclonal antibodies (mAb) and complement. These preparations consisted of 64-82% TcR gamma/delta+ lymphocytes, as indicated by the sum of cells reacting with the BB3 and A13 mAb which define two distinct, nonoverlapping, TcR gamma/delta+ cell subsets in the peripheral blood. TcR gamma/delta cells were able to form conjugates with the natural killer-sensitive K-562 and with the natural killer-resistant HL-60-R tumor cell lines. The cytochemical localization of lysosomal acid hydrolases showed that 95%-98% of the cells in the TcR gamma/delta+ preparations had the morphologic features of granular lymphocytes. Moreover, electron microscopy analyses showed that TcR gamma/delta+ cells had electron-dense granules dispersed in the cytoplasm and a variety of smooth vesicles, a morphology identical to that of other CD3- or CD3+ granular lymphocyte subsets. Freshly isolated TcR gamma/delta+ cells were unable to lyse K-562 and natural killer-resistant targets, such as HL-60-R and P815. However, low levels of target cell lysis were observed upon triggering of the effectors by anti-CD3 TcR mAb or by lectin. After short-term culture with interleukin 2, TcR gamma/delta+ cells acquired a strong cytolytic activity against K-562 and HL-60-R target cells in the absence of triggering stimuli, and also displayed high levels of cytolytic activity against P815 in the presence of anti-CD3/TcR mAb.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1989

An SEM analysis of the interaction between lymphokine-activated killer cells and tumor targets.

The interaction between lymphokine-activated killer (LAK) cells and two types of target cells with different susceptibility to natural killer (NK) activity was investigated by scanning electron microscopy (SEM). In NK-susceptible tumor cells (K562) a different mode of conjugation with the effector was observed as compared with NK-resistant targets (THP-1-0). In LAK-K562 pairs, the contact region was characterized by the presence of long microvilli, blebs and ruffled membranes forming an intertwined and interdigitated binding site. Conversely, when LAK cells were conjugated with THP-1-0 cells, the surface structures of the target cell did not undergo significant modification and the interacting cells did not appear to establish close contact. In addition, cell lysis of the sensitive target was often characterized by plasma membrane blebbing, leading to cell death. In contrast, in the low percentage of resistant targets which underwent lysis after conjugation, cell death always occurred without formation of bulb- or bleb-like structures.

Cytotoxicity, Immunologic↗
PubMed1989

Human T cells expressing the gamma/delta T-cell receptor (TcR-1): C gamma 1- and C gamma 2-encoded forms of the receptor correlate with distinctive morphology, cytoskeletal organization, and growth characteristics.

BB3 and delta-TCS1 monoclonal antibodies identify two distinct nonoverlapping populations of T-cell receptor (TcR) gamma/delta (TcR-1)-positive cells, which express a disulfide-linked and a nondisulfide-linked form of TcR, respectively. BB3+ cells represented the majority of circulating TcR-1+ cells, but they were virtually undetectable in the thymus. On the other hand, delta-TCS1+ cells were largely predominant among TcR-1+ thymocytes but represented a minority in peripheral blood (PB). Similar distributions were observed by clonal analysis of thymocytes or PB TcR-1+ populations. The use of joining region (J)-specific probes indicated that BB3+ and delta-TCS1+ clones displayed different patterns of J rearrangement. Thus, the disulfide-linked form of TcR-1 (BB3+ clones) was associated with the expression of J segments upstream to the C gamma 1 gene segment, whereas the nondisulfide-linked form (delta-TCS1+ clones) was associated with the expression of J segments upstream to C gamma 2. delta-TCS1+ clones, in most instances, exhibited a growth pattern different from that of BB3+ or conventional TcR alpha/beta+ clones as they adhered promptly to surfaces, spread, and emitted long filopodia ending with adhesion plaques. Ultrastructural analyses showed, exclusively in delta-TCS1+ cells, nuclear deformations, uropod formation, and abundant cytoskeletal structures. In addition, immunofluorescence studies of this subset of TcR-1+ cells revealed the presence of abundant microtubules, intermediate filaments, and submembranous microfilaments. Thus, our findings suggest that delta-TCS1+ cells are capable of active motility.

Blotting, Southern↗
PubMed1989

A scanning electron microscopy analysis of human cytotoxic cell subsets and of their mode of conjugation with tumor cell targets.

In this study we describe the surface features of non-MHC (Major Histocompatibility Complex)-restricted cytotoxic cells isolated from human peripheral blood. Purified populations of CD3-, natural killer (NK) cells were allowed to interact with NK-sensitive (K562) and NK-resistant (THP-1-0) tumor cell targets. The type of effector to target cell binding was investigated by scanning electron microscope (SEM) analysis. A different interaction with the effectors is described for NK-resistant targets in comparison with NK-susceptible tumor cells. SEM was also used to investigate the relationship between interleukin 2 (IL2)-activated cytotoxic cells (lymphokine-activated killer, LAK, cells) and the tumor targets. We also describe the unique growth features of certain clones of cytotoxic T cells expressing gamma delta antigen receptors which support the contention that these cells may have a special ability of homing into tissues. We conclude that non-specific cytotoxic cells constitute a diverse population of effectors which differ not only for the expression of surface antigens, but also for their ability to interact with tumor cell targets and to home into the peripheral tissues where they may exert their lytic functions.

Cell Survival↗
PubMed1987

Relationship between target cell cycle and susceptibility to natural killer lysis.

Studies from several laboratories have evaluated the role of cell surface antigenic molecules on target cells in natural killer (NK)-mediated cytotoxicity. A number of these cell surface molecules are associated with cell proliferation and may be expressed preferentially during one phase of the cell cycle. The purpose of this investigation was to evaluate the role that target cell cycle plays in susceptibility to NK lysis. Enrichment (greater than 80%) of cells from NK-resistant and NK-sensitive cell lines in the G0G1, S, and G2M phases of the cell cycle was achieved by centrifugal elutriation. We demonstrate that there was no influence of cell cycle on NK-mediated lysis of NK-resistant or susceptible cell lines.

Cell Cycle↗
PubMed1987

Human leukemia-derived cell lines and clones as models for mechanistic analysis of natural killer cell-mediated cytotoxicity.

Tumor target cells (TC) are lysed by natural killer (NK) cells provided that they (1) form conjugates with the effector cells, (2) activate effector cells to release cytotoxic factors, and (3) they are susceptible to the lytic effect of these factors. While this cascade of events that leads to TC killing has been defined, the signal molecules responsible for each of the steps remain largely undetermined. A variety of human leukemia-derived TC lines and clones were analyzed for their sensitivity to NK cell-mediated lysis and for their ability to bind and activate NK cells. These characteristics have been correlated with TC surface expression of differentiation antigens and carbohydrate residues. Of the cell lines and clones tested, K562, SPI-802, MOLT-4, MOLT-4/C8-1, ZS, KG-1/A-3, and HL-60S were sensitive to NK cell-mediated lysis, while KG-1, THP-1-0, HL-60R, and LFM were resistant. KG-1, THP-1-0, HL-60R, and LFM cells were further studied to determine mechanisms responsible for their resistance to NK cells. It was found that HL-60R and LFM cells were unable to bind NK cells. In contrast, KG-1 and THP-1-0 cells were able to bind to and activate NK cells. Therefore, it is likely that the NK-resistance of KG-1 and THP-1-0 cells may be related to their lack of sensitivity to cytotoxic factors released by bound NK cells. All of the TC cell lines and clones capable of binding NK cells expressed the 3-fucosyl-N-acetyl-lactosamine hapten (Lex or SSEA-1 antigen) recognized by the monoclonal antibody Leu M1. These TC consistently lacked surface L-fucose residues, as shown by lack of Ulex europaeus agglutinin binding. In contrast, HL-60R and LFM which did not form conjugates with NK cells, did not express surface Lex determinants and avidly bound the Ulex agglutinin. Distinct subpopulations of NK-resistant KG-1 cells expressed Lex antigens or bound Ulex. We compared KG-1/A-3, a NK-sensitive cell clone, with the parental NK-resistant KG-1 cell line. KG-1/A-3 lost the ability to bind the Ulex lectin displayed by the parental cell line and showed increased expression of Lex determinants. Results from these phenotypic analyses suggest that expression of Lex determinants and Ulex binding sites on the TC membrane are mutually exclusive and their expression or absence may correlate with mechanisms which regulate TC-NK cell interactions.

Cell Line↗
PubMed1987

Ultrastructural analysis of human natural killer cell activation.

In this study we describe characteristic ultrastructural changes of CD3- large granular lymphocytes (LGL), ie, natural killer (NK) cells, following stimulation with recombinant (r) interleukin 2 (IL 2) or r-gamma interferon (r-gamma IFN) and after interaction with K562 target cells (TC) or Sepharose-bound anti-Fc gamma receptor (FcR) monoclonal antibody (MoAb). When compared to resting cells the cytolytic activity of r-IL 2- and r-gamma IFN-stimulated cells against K562 TC was enhanced. The r-IL 2-stimulated LGL were larger and consistently displayed the shape and cytoskeletal rearrangement characteristic of activated cells. The Golgi apparatus was expanded, and the number of electron-dense granules and vesicles was increased. The ultrastructural changes in r-gamma IFN-stimulated LGL were markedly different from those observed following r-IL 2 activation. Cells did not exhibit changes in size, shape, cytoskeletal organization, or in the structure of the Golgi apparatus. However, r-gamma IFN-stimulated cells exhibited distinctive changes in the structure and content of electron-dense granules with deaggregation of the matrix and parallel tubular arrays (PTAs). Within organelles apparently derived from the electron-dense granules, vesicular and tubular structures were noted that may be the morphological equivalent of cytotoxic factors produced by cytolytic effector cells. These ultrastructural observations indicate that r-IL 2 and r-gamma IFN enhance the lytic ability of NK cells by acting on distinct cell machineries. The cytolytic ability was decreased when LGL were pretreated with K562 TC or immobilized anti-FcR antibody. In both experimental conditions cells displayed ultrastructural features indicating activation as well as loss of cytoplasmic granules and other Golgi-derived organelles. Stimulation of r-gamma IFN- or r-IL 2-activated LGL with K562 TC or Sepharose-bound anti-FcR antibody decreased their cytolytic ability, with cells depleted of granules at the ultrastructural level. Intracytoplasmic fusion of granules and a massive release of the granule content were found in r-IL 2-stimulated cells, reminiscent of the mechanism of basophil degranulation. These observations suggest that multiple activation signals involving distinct surface membrane molecules induce release of cytolytic factors by both resting and activated NK cells.

Cell Line↗
PubMed1987

Ultrastructural morphology of granular lymphocytes (GL) from patients with immunophenotypically homogeneous expansions of GL populations (GLE).

We studied the morphology of large granular lymphocytes (GL) from 19 patients with expanded populations of GL (GLE) of homogeneous surface immunophenotype. By definition, all patients had increased numbers of medium-sized lymphocytes with azurophilic granules, and neutropenia, thrombocytopenia, and/or anemia. In all cases, the GL had an extended Golgi apparatus and prominent centrioles. Among cells from individual patients, the GL were homogeneous with respect to their granule morphology. GL containing parallel tubular arrays (PTA), commonly associated with GLE, were observed in 9 of 19 cases; granules containing scarce matrix with or without associated vesicles (SMG) were present in the remaining 10 cases. In all cases in which the cells had PTA, there was co-expression of CD3 and CD8, the T suppressor cell-associated phenotype, whereas only 4 of 10 cases with SMG expressed CD3 and CD8 (p less than 0.01, chi-square test). We conclude that the morphologic homogeneity of GL in individual patients with GLE differs significantly from the heteromorphism usually seen in reactive GL, and is consistent with, but not diagnostic of, a clonal proliferation of GL in persistent GLE.

Antibodies, Monoclonal↗
PubMed1986

Flow cytometry evaluation of cell-mediated cytotoxicity.

A novel flow cytometry method for the evaluation of cell-mediated cytotoxicity is described. This method uses flow cytometry analysis to distinguish target cells from effector cells by differences in volume and light scatter characteristics. Non-viable target cells, following their interaction with effector cells, are determined via propidium iodide (PI) dye exclusion and then expressed as a percentage of the total target cell population. This assay is suitable both for analysis of systems which allow recycling of cytotoxic effector cells (total cell cytotoxicity assays, TCCA), and of systems in which recycling does not occur (single cell cytotoxicity assays, SCCA). Natural killer (NK) cell-mediated cytotoxicity evaluated by flow cytometry is significantly correlated with the standard 51Cr release assay. Flow cytometry can also be used to evaluate the competitive inhibition that certain cell types exert on the cell-mediated killing of NK-sensitive targets. A prerequisite for this assay is that competitor cells and target cells are distinguishable through their volume and light scatter characteristics. Advantages and pitfalls of the flow cytometry method are discussed, in comparison with the 51Cr-release assay.

Adult↗
PubMed1986

Hypercoagulable state induced by cytostatic drugs in stage II breast cancer patients.

An increased incidence of thromboembolic complications occurring in cancer patients during chemotherapy was recently reported. In view of this report, a study in 49 patients receiving adjuvant chemotherapy for Stage II breast cancer was begun in order to determine the effect of antineoplastic drugs on coagulation factors and platelet function. Among the coagulation factors, a significant decrease of thrombin time and partial prothrombin time was observed, whereas platelet function tests were unchanged. This finding suggests a trend towards hypercoagulability induced by chemotherapy. This effect should be considered when chemotherapy is employed in advanced cancer patients at high risk for thrombosis.

Adult↗