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D S Hoon

Publications and source records attributed to D S Hoon.

At least 91 records · Page 5Linked to original sources
PubMed1989

Active specific immunotherapy in malignant melanoma.

We have recently initiated clinical trials of active specific immunotherapy evaluating a new polyvalent melanoma cell vaccine in patients with high-risk and/or recurrent melanoma. The vaccine has been administered alone, or in combination with low-dose cyclophosphamide, as an immunomodulator of suppressor cells. Cyclophosphamide is effective in lowering suppressor cell activity in some patients undergoing active specific immunotherapy. This is not associated with an enhanced humoral immune response to melanoma-associated antigens, nor is the clinical course of those patients receiving cyclophosphamide favorably influenced. We are hopeful that other immunomodulators, alone or in combination with lower doses of cyclophosphamide, may be effective in some patients, particularly in those patients whose suppressor cell activity remains high. The optimization of the vaccine and the use of immunomodulators will enhance humoral and cellular immune responses to antigens in the allogenic vaccine that cross react with those present in the autologous melanoma, which should more favorably influence the prognosis of melanoma patients.

Antigens, Neoplasm↗
PubMed1989

S-100 protein stimulates cellular proliferation.

S-100 protein (S-100p) is a small, acidic, calcium-binding protein that is present (predominantly) in the cytoplasm of many types of cells including those of neuroectodermal origin, such as glial cells, schwann cells and melanocytes. In human melanoma cells S-100p is abundant relative to the small quantities expressed by normal melanocytes. We investigated the possibility that this protein may be a growth factor. Purified S-100p from bovine brain or human melanoma cells was added exogenously to human melanoma cells and peripheral blood lymphocytes (PBL) and their growth in the presence of different concentrations of S-100p was determined using a [3H]dT-uptake proliferation assay. The growth of melanoma cells was stimulated by S-100p at concentrations of 1.95-31.25 micrograms/ml. Slight inhibition of cell proliferation occurred at high concentrations (125 micrograms/ml). Maximum stimulation of PBL was at 31.25 micrograms/ml. PBL were not inhibited even at high concentrations of S-100p (125 micrograms/ml). PBL stimulation by S-100p did not require the presence of monocytes/macrophages. Though stimulation by S-100p is not restricted to a specific cell type, when released by melanoma cells it may function as an "autocrine" tumor growth factor. Other cells, such as PBL, coming in contact with S-100p are also stimulated to proliferate.

Cell Cycle↗
PubMed1989

Variations in lymphokine generation by individual lymph nodes draining human malignant tumors.

Individual lymph nodes draining tumors vary in their degree of immunological activity. Cell suspensions from tumor-free nodes located relatively near to tumors are spontaneously less reactive and respond poorly to exogenous stimulation by mitogens and lymphokines. Diminished spontaneous uptake of tritiated thymidine by lymph node cells not exposed to exogenous stimulation suggests that tumor-proximate immune suppression exists in vivo and is not purely a laboratory artefact. The present study was undertaken to explore that possibility further. Fluid in which cell suspensions from tumor-free nodes were prepared, and supernatants from short-term cultures of nodes located at different distances from tumors were compared for their capacity to inhibit the in vitro migration of the human lymphoblastoid cell line QIMR-WIL. Inhibitory activity of fluids from individual nodes was related to their position relative to the tumor and their immune competence, assessed by the responses to mitogens of cell suspensions prepared from them. Cell suspension fluids from 92/111 nodes (83%) significantly inhibited the migration of QIMR-WIL, at a level similar (44 +/- 14%) to that induced by the supernatants of mixed lymphocyte cultures (43 +/- 17%). Fluids from the nodes of melanoma patients were more inhibitory than those from breast cancer patients (49 +/- 12% and 37 +/- 13%, respectively, P = 0.003). The inhibitory activity of the different nodes of individual node groups varied significantly in 25 of 33 patients (76%), the node nearest the tumor generating least inhibitory activity (indexing the greatest immune suppression) in 20 of these 25 patients (80%). The strength of migration-inhibitory activity was concordant with the responsiveness to mitogen stimulation in up to 14 of 18 patients (78%). Studies of molecular size and heat stability indicated that the inhibitory factors had characteristics consistent with common migration-inhibitory lymphokines such as leukocyte-migration-inhibitory factor, macrophage-inhibitory factor and interleukin-2. Our findings further support the hypothesis that lymph nodes nearest to tumors are relatively immune-suppressed in vivo.

Body Fluids↗
PubMed1989

Modulation of human macrophage functions by gangliosides.

In human tumors of neuroectodermal origin cell surface expression of individual gangliosides is either increased or decreased relative to comparable normal cells. We have previously shown that gangliosides shed from melanoma cells can immunomodulate T cell activity. Monocytes/macrophages (m/m) are known to play an important role as accessory and effector cells in immune responses. We therefore investigated the effect of exogenous gangliosides derived from melanoma on m/m functions in vitro. Gangliosides commonly expressed on human melanoma such as GM3, GD3, GM2, and GD2 were investigated, as well as GM1, a major component of human neural tissue. Monocytes were isolated from human peripheral blood mononuclear cell populations, treated with gangliosides in vitro, and evaluated in several functional assays. Treatment of m/m with GM2 and GM3 gave the greatest inhibition of Fc receptor expression. GM1 and GD3 on the other hand most inhibited the production of interleukin-1 (IL-1) by m/m. Production of tumor necrosis factor (TNF) like monocytoxin was not affected by incubation with individual gangliosides. These studies suggest that individual melanoma gangliosides have different regulatory effects on m/m functions.

Gangliosides↗
PubMed1988

Gangliosides from human melanoma immunomodulate response of T cells to interleukin-2.

The gangliosides expressed by normal melanocytes are predominantly GM3 (greater than 90%) and GD3 (less than 5%). Malignant melanoma can express several other types of gangliosides in significant quantities, including GM2 and GD2. Melanoma patients can develop an immune response against some of these ganglioside antigens on autologous melanoma cells. The four major gangliosides expressed by human melanoma cells (GM3, GD3, GM2, and GD2) were examined for their immunomodulatory effect on lymph node lymphocytes from melanoma patients. Gangliosides were added exogenously to lymphocytes grown in the presence of IL-2. Preferential interactions of specific melanoma gangliosides on IL-2 stimulation were found. While GM2 and GD2 enhanced the lymphocyte response to IL-2, GM3 and GD3 significantly inhibited this response. GM2 and GD2 differ from GM3 and GD3 by the presence of a terminal N-acetylgalactosamine. Since different gangliosides can up-regulate and down-regulate lymphocyte responses to IL-2, the ganglioside phenotype of melanoma cells may play a major role in determining whether an individual tumor causes immune stimulation or suppression.

Cell Survival↗
PubMed1988

A comparison of solutions for lung preservation using pulmonary alveolar type II cell viability.

Many special solutions have been developed to protect the ischemic lung in preparation for transplantation. To determine an effective solution, we isolated pulmonary alveolar type II cells from rat lungs. These cells play an important role in sodium transport and the production of surfactant; thus, they are crucial to the respiratory physiology of the lung. In this study, we examined in vitro the effect of various solutions such as Collins' solution, Collins-Sacks solution, and glucose-insulin-potassium solution on alveolar type II cell viability. The cell viability was examined with a trypan blue dye exclusion test and [3H]thymidine uptake proliferation assay after 24 and 72 hours of incubation. The alveolar type II cells in the glucose-insulin-potassium solution had greater viability compared with cells cultured in either Collins' or Collins-Sacks solution. This study demonstrates that glucose-insulin-potassium solution has the least toxic effect on isolated alveolar type II cells compared with other preserving solutions.

Animals↗
PubMed1987

Isolation of lymphocytes from clotted blood.

A problem often faced in clinical cell-mediated immunology research is to obtain peripheral blood lymphocytes (PBLs) in sufficient numbers to carry out cellular immune assays. Obtaining sufficient amounts of blood for serum is usually more practical than for PBLs. Blood is usually drawn easily for serum, but obtaining PBLs from clotted blood has not been very practical. In this report we describe a procedure whereby PBLs can be recovered from clotted blood and used in functional immune assays. Using the enzyme streptokinase (SK) blood clots were dissolved and viable PBLs recovered up to 24 h post clotting. Concentrations of SK from 250 to 500 SK U/ml gave maximum recovery of PBLs.

Blood Coagulation↗
PubMed1987

Ganglioside GM2 on the K562 cell line is recognized as a target structure by human natural killer cells.

Although human NK cells lyse a wide spectrum of target cells, the precise target structure recognized by NK cells has not yet been elucidated. In order to define a possible relationship between gangliosides on human target cells and susceptibility to NK lysis, 14 human leukemia and lymphoma cell lines were studied. A significant correlation was observed between the quantity of ganglioside GM2 on the target cells and sensitivity to NK lysis. In a single-cell binding assay purified GM2 specifically inhibited human NK cell binding to K562 target cells while other gangliosides did not inhibit binding. The competitive inhibition of NK cells by GM2 was restricted to the source of tissue from which GM2 was isolated. These results indicate that GM2 is a strong candidate as a target recognition structure for human NK cells.

Binding Sites↗
PubMed1987

Suppressor cell activity in melanoma-draining lymph nodes.

We previously demonstrated that the cells of lymph nodes near to a melanoma respond well to stimulation by mitogens, alloantigens, and interleukin 2 than do nodes further away. In this study we examined suppressor T-cell activity in nodes at different distances from primary melanoma, using a concanavalin A (Con A) suppressor cell assay. Tumor-free regional nodes were classified as proximal, intermediate, and distal relative to primary melanoma. Lymph node lymphocytes (LNL) were stimulated with 50 micrograms/ml Con A for 48-72 h, inactivated, and then mixed with autologous peripheral blood lymphocytes. The peripheral blood lymphocyte-LNL mixtures were stimulated with phytohemagglutinin for 3 days. Proliferation was measured by [3H]thymidine uptake during the final 18 h of culture. In 13 patients, Con A-treated LNL from nodes near to tumor were more suppressive of the peripheral blood lymphocyte response to phytohemagglutinin than those from nodes located further from tumor. T-lymphocyte subset assessment before and after Con A treatment of LNL showed no significant changes in T4:T8 ratios. Con A-induced suppressor cells could be maintained in culture in the presence of recombinant interleukin 2 and retained their suppressive activity. LNL not exposed to Con A and maintained in culture with interleukin 2 did not show suppressor cell activity. Suppressor cell activity thus contributes to the weak immune reactivity of lymph nodes near to melanoma.

Concanavalin A↗
PubMed1987

Variations in functional immunocompetence of individual tumor-draining lymph nodes in humans.

In studying the histology and immunohistology of tumor-draining lymph nodes, we observed that nodes close to tumor showed reduced paracortical activity relative to those further away. To assess whether this reduction was paralleled by alterations in the functional activity of nodes, we examined the immunocompetence of individually oriented tumor-draining lymph nodes. We assessed the unstimulated activity of lymph node lymphocytes and their responses to phytohemagglutinin, interleukin 2, and one-way alloantigenic stimulation (mixed lymphocyte reaction) in vitro. Regional nodes from patients with malignant melanoma or breast cancer were classified as proximal, intermediate, or distal relative to tumor. Node groups with and without tumor metastases in them were studied. Significant variations in [3H]thymidine uptake were noted with the unstimulated and stimulated lymphocytes of different lymph nodes from the same individual. Nodes near to tumor were less responsive than those located further away; some of the latter showed relative immunostimulation. Tumor-draining node groups thus demonstrated a nonrandom variation in the strength of reaction of individual nodes. There are zones of low and high lymph node reactivity, related to the position of each node relative to tumor. Tumor-derived immunosuppressive products and/or immunoregulation down-regulates lymph node functional activity, creating conditions that may permit the survival of tumor cells and the establishment of metastases. It is suggested that immunosuppression of nodes nearest to tumor may facilitate the early establishment of metastases.

Humans↗
PubMed1987

A 6-thioguanine-resistant variant of the rat mammary adenocarcinoma 13762 that is more immunogenic.

A 6-thioguanine-resistant (TgR) variant of the metastatic mammary tumor 13762 was found to be very immunogenic. This TgR variant was nontumorigenic and nonmetastatic, whereas the parent 13762 cell line is very tumorigenic and metastatic in normal syngeneic animals. The TgR variant was tumorigenic in irradiated animals. The mechanism of the hosts' immune rejection of this TgR variant was investigated. A 51Cr-release cytotoxic cell assay was used to assess lymphocyte cell-mediated cytotoxicity (CMC) of tumor-draining lymph nodes and spleens from animals injected with tumor cells. In a secondary CMC response of splenic T cells from animals injected with TgR cells, there was a much stronger response as compared to animals injected with 13762 cells. This strong cytotoxic T cell response was short-term and correlated to the host rejection of TgR cells. Previously, we selected revertant cell lines (TgRrev, TgRrevM) from the TgR variant line that were more metastatic and tumorigenic. The revertant cell lines induced a lower CMC response than the TgR line, but a higher response compared to the parent 13762 line. The poor CMC response from 13762 tumor-bearing animals was investigated and appeared to be due to a suppressor T cell response.

Adenocarcinoma↗
PubMed1987

The regulatory effect of adherent cells on lymphokine activated killer cells.

We analyzed the effect of adherent cells on the induction of lymphokine-activated killer (LAK) cell activity by depleting adherent cells from peripheral blood lymphocytes (PBL) or by adding adherent cells to PBL before culture with interleukin-2. We found that adherent cells clearly down-regulate LAK cell induction. These inhibitory effects are dependent on the number of adherent cells added. Inhibitory effects of adherent cells are abolished by the addition of indomethacin to the LAK culture. Soluble factors derived from adherent cells, such as interferons and interleukin-1, have a slight enhancing effect on LAK induction. In contrast, adherent cells appear to inhibit LAK induction primarily by producing prostaglandin E2(PGE2). PGE2 in turn inhibits the induction of LAK effector cells by inhibiting the expression of the transferrin receptor on LAK cells. These effects are manifested most strikingly in the early phases of LAK induction.

Biological Products↗
PubMed1987

Reactivity of neoplastic cells of hairy cell leukemia with antisera to S-100 protein.

Rabbit antibodies to bovine S-100 protein were tested by immunoperoxidase technics against fresh hairy cell leukemia (HCL) cells obtained from nine patients (peripheral blood in six and spleen in three), as well as lymphoblastoid cell lines derived from three patients with HCL. Peripheral mononuclear cells from three normal persons and two patients with chronic lymphocytic leukemia (CLL) and cells from two melanoma lines were used as controls. The melanoma cell lines, cell lines derived from patients with HCL, and fresh HCL cells displayed cytoplasmic and nuclear positivity after exposure to anti-S-100 protein sera. By contrast, normal peripheral blood lymphocytes and CLL cells were negative for S-100 protein. Additional studies were performed by immunoperoxidase technics on representative sections of formalin-fixed splenic tissues from eight patients who had splenectomies. The cause of splenectomy was HCL in three, traumatic rupture in one, CLL in one, Hodgkin's disease in one, and hypersplenism in two patients. Sections from all three HCL patients showed moderate to marked positivity with antisera to S-100 protein. These results strongly suggest the presence of S-100 protein in HCL cells.

Animals↗
PubMed1987

Zoned immune suppression of lymph nodes draining malignant melanoma: histologic and immunohistologic studies.

Node-to-node heterogeneity of reaction and recognizable patterns of reaction in node groups draining melanoma were sought. Nodes from 72 patients undergoing lymphadenectomy for high-risk, primary melanoma (57) or node-spread melanoma (15) were accurately oriented to the nearest melanoma. Reactivity of paracortex, follicular areas, and sinuses was assessed on a 0-3+ scale. Reactivity was prominent in paracortex and sinuses but varied from node to node within node groups. Nodes nearest to tumor showed least reaction; nodes at intermediate distances from tumor were most reactive, while those farthest away showed mostly little reaction. Variation of nodal reaction that correlated with the node position relative to the nearest melanoma (zoned reaction) was seen in 92% of patients with nodal metastases of melanoma and in 64% of patients with primary malignant melanoma. Follicular and sinusoidal reactions showed no significant zoning. S-100 protein-positive paracortical dendritic cells (PDCs) in tumor-oriented nodes were quantified. PDCs were infrequent in nodes partly replaced by melanoma or located near to melanoma but were numerous in nodes located farther from tumor. Changes of nodal activity (relative stimulation or suppression) correlate with the distance of the node from the nearest deposit of primary or metastatic melanoma.

Humans↗
PubMed1986

Inhibition of lymphocyte motility by interleukin 2.

These studies described were designed to determine whether interleukin 2 (IL-2) inhibits lymphocyte migration. The human lymphoblastoid cell line QIMR-WIL was used as an indicator of lymphocyte migration inhibition. Interleukin 2 inhibited QIMR-WIL migration in a dose-dependent manner, high doses of IL-2 (100 units) being strongly inhibitory, and low doses (12.5 units) less inhibitory. Purified natural IL-2 and recombinant IL-2 both inhibited QIMR-WIL migration. The effect of IL-2 on lymphocyte migration was specific. When the IL-2 receptors were blocked with anti-Tac (anti-IL-2 receptor) antibodies, the inhibitory effect of IL-2 was significantly reduced. Similarly antibody to IL-2 blocked the inhibitory effect of IL-2. Lymph node lymphocytes were also used as indicator cells in migration studies and IL-2 inhibited their motility. These data suggest a role for IL-2 in inhibiting lymphocyte migration similar to that of lymphocyte migration inhibition factor produced by antigen- or mitogen-stimulated T lymphocytes. While it is widely recognized that lymphocyte motility can be reduced by lymphocyte migration inhibition factor, these data indicate that IL-2 can also reduce lymphocyte motility.

Cell Line↗
PubMed1985

Chemoimmunotherapeutic effect of cyclophosphamide on the highly metastatic MAT 13762 tumor.

We have observed that cyclophosphamide (CY) treatment of 13762 mammary adenocarcinoma tumor-bearing rats was found to cause tumor regression. Tumor-bearing animals cured with three low doses of CY were partially immune against IV and SC challenge with a high dose of 13762 cells. This immune protection mechanism in CY-cured animals appears to be a T (Ig-) cell-mediated response. Irradiated rats reconstituted with CY-cured animal spleen cells were also partially protected against IV and SC challenge with 13762 cells, whereas irradiated rats reconstituted with CY-control animal spleen cells were not. In vitro primary and secondary cell-mediated cytotoxic activity of CY-cured spleen cells against target 13762 cells was low. The possible relevance of this tumor-model study is in the understanding of CY-induced tumor immune response and its role in preventing metastases or perhaps recurrent tumor growth.

Adenocarcinoma↗
PubMedDate not supplied

Functional interleukin-4 receptor and interleukin-2 receptor common gamma chain in human gastric carcinoma: a possible mechanism for cytokine-based therapy.

Interleukin (IL)-2 and IL-4 play a critical role in the regulation of the immune response. Yet both of the receptors for these cytokines have been found on nonhematopoietic cells, including human gastric carcinoma cell lines and tissue specimens. IL-4 causes G1 phase cell cycle arrest of gastric carcinoma; the effect directly correlates with the expression of IL-4 receptor (IL-4R) and is seen within 48 hours after treatment. Cells lacking IL-4R are unaffected by IL-4. We examined signal transduction pathways employed by IL-4 that may account for cell cycle arrest of an established human gastric carcinoma cell line, CRL 1739. Western blot analysis was performed on CRL 1739 cultured in the presence of IL-4 (500 U/ml). Cells were lysed, protein extracted, and electroblotted; blots were then probed with murine mono-clonal antibodies to specific intracellular proteins. Western blotting of CRL 1739 with antiphosphotyrosine antibody (4G10) demonstrated multiple (140 kDa and 65 kDa) phosphoproteins seen only in IL-4-treated CRL 1739. Immunoprecipitation and blotting of CRL 1739 with specific secondary antibodies demonstrated that the 140 kDa phosphoprotein was IL-4R", the 65kDa phosphoprotein was IL-2Rgc, the 130 kDa phosphoprotein was Janus kinase (JAK1), and the 116 kDa phosphoprotein was JAK3. Reverse transcription-polymerase chain reaction with specific primers demonstrated that multiple human gastric tumor specimens expressed IL-4R" and IL-2Rgc but did not express the leukocyte marker CD45. These results suggest that human gastric carcinomas may express functional cytokine receptors, including the IL-2Rgc commonly found in association with the lymphocyte IL-2R. These receptors may represent novel targets for directing cytokine-based therapy.

Biopsy↗