Differential activation of lymphokine-activated killer cells with different surface phenotypes by cultivation with recombinant interleukin 2 or T-cell growth factor in gastric cancer patients

Augmented human-tumor-cytolytic activity of peripheral blood lymphocytes and cells from a mixed lymphocyte/tumor culture activated by interleukin-12 plus interleukin-2, and the phenotypic characterization of the cells in patients with advanced carcinoma

In this study, we evaluated the ability of combination regimens of interleukin-12 (IL-12) and interleukin-2 (IL-2) to induce effective killer cells against human tumors in vitro, in peripheral blood lymphocytes (PBL) from 15 cancer patients and mixed lymphocyte/tumor culture (MLTC) cells from 16 cancer patients, and carried out a phenotypic analysis of the cells responsible for the lysis of the human tumors. The freshly prepared PBL were cultivated with IL-2 alone or IL-12/IL-2 for 10 days [lymphokine-activated killer (LAK) cell generation system]. The MLTC cells (PBL cultured with mitomycin-C-treated allogeneic G-415 tumor cells for 3 days) were further cultivated with IL-2 or IL-12/IL-2 for 7 days [cytotoxic T lymphocytes (CTL) generation system]. The cytolytic activities of the lymphoid cells cultivated with IL-12/IL-2 were significantly augmented in both the LAK and CTL generation systems, as compared with those of cells treated with IL-2 alone. In the LAK generation system, the cytolytic activities of the cells cultivated with IL-12/IL-2 were significantly decreased by the method of negative selection of CD11b- or CD56+ cells using immunomagnetic beads. The CD8(+)-depleted cells showed a slight decrease of activity. The killer cell activities of the CD4(+)-depleted cells remained unchanged. In the CTL generation system, the activity was markedly reduced by the elimination of the CD8+ or CD11b+ or CD56+ cells. The combined data suggested that IL-12/IL-2-induced killer effector cells in the LAK generation system were mainly of the natural killer (NK) type, comprising CD8-CD11b+, CD8- CD16b+, CD3-CD56+, and partly possible CD8+ CD11b- T cells. CD8+ CD11b- T cells mixed with cells of the NK type, comprising CD8-CD11b+, CD8- CD16b+ and CD3-CD56+ cells, were the population of killer effector cells induced by IL-12/IL-2 in the CTL generation system.

Immunosuppressive effect of shedding intercellular adhesion molecule 1 antigen on cell-mediated cytotoxicity against tumor cells

We have examined whether shedding intercellular adhesion molecule-1 (ICAM-1) antigen from cultured tumors is able to inhibit the leukocyte function-associated antigen-1 (LFA-1)/ICAM-1 interaction between cytotoxic effector cells and ICAM-1+ target tumor cells. The cytotoxic activity of lymphokine-activated killer (LAK) cells incubated with spent media from ICAM-1+ tumor cells, especially interferon-gamma-stimulated tumor cells, was significantly decreased as compared with that of LAK cells treated with fresh culture medium without ICAM-1 antigen. Treatment of LAK cells with spent media from ICAM-1- tumor cells did not cause a significant decrease of the cytolytic activity towards ICAM-1+ tumor cells. These findings suggest that shedding of ICAM-1 antigen could be involved in binding of LFA-1 to LAK cells, resulting in reduced cytolytic activity.

Phenotypic analysis of nylon-wool-adherent suppressor cells that inhibit the effector process of tumour cell lysis by lymphokine-activated killer cells in patients with advanced gastric carcinoma

The causes of down-regulation of cytotoxic immune responses in cancer patients have not been fully evaluated. We previously demonstrated that T-cell-growth-factor-activated peripheral blood lymphocytes (PBL) with the surface phenotype CD8+ CD11b-, from patients with widespread metastasis of gastric carcinoma, inhibited the effector process of lymphokine-activated-killer(LAK)-cell-mediated cytolysis. In this study, we examined suppressor cell activity in freshly prepared PBL from 18 patients with advanced gastric carcinoma, and 10 normal healthy individuals. The suppressor cell activity was assayed by recording whether or not PBL inhibited directly the effector process of LAK cell cytotoxicity. Most of the PBL suspensions from cancer patients showed that they contained a population of cells that can directly inhibit the effector phase of tumor cell lysis of the cytotoxic cells. To analyze further the PBL responsible for the suppression, the cells were passed over a nylon-wool column. Nylon-wool-adherent cells significantly augmented the suppression, while the cells passing through abrogated the suppressive effect. Most nylon-wool-adherent cells from 10 normal healthy controls did not inhibit the cytotoxic reaction. To determine further the suppressor-effector population in nylon-wool-adherent cells, negative-selection studies using CD8-, CD4- or CD11b-coated magnetic beads, and positive-selection studies using CD8- or CD4-coated magnetic beads were performed. Finally the results suggest that the suppressor-effector cells comprise at least two different surface phenotypes: CD8+ T and CD8-CD11b+ cells. The possible role of CD4+ T cells and HLA-DR+ LeuM3+ macrophages as suppressor cells was ruled out in nylon-wool-adherent cells. CD8+ T and possibly CD8-CD11b+ cells apparently suppressed the efferent limb of the antitumor immunity. The selective immune suppression mediated by these cells may partly be concerned with escape mechanisms of gastric carcinoma from the host immune surveillance system.

Expression of intercellular adhesion molecule 1 (ICAM-1) during the development of invasion and/or metastasis of gastric carcinoma

In this study, using two-color flow-cytometric analysis, we examined the expression of histocompatibility locus antigens (HLA) classes I and II, and intercellular adhesion molecule 1 (ICAM-1) in 10 cases of normal gastric mucosa, 13 cases of primary carcinoma on the stomach, 16 cases of metastatic carcinoma from malignant ascites in patients with gastric carcinoma and 14 samples of their cultured carcinoma cells. Compared with normal gastric mucosa, HLA class I were highly expressed in a considerable number of tumor cells in each experimental group. The expression of HLA class II tended to reduce in the order of normal gastric mucosa, primary gastric carcinoma and peritoneal-effusion-associated carcinoma. Altogether, 85.7% of cases of cultured tumor cells showed abrogation and loss of HLA class II. The ICAM-1 molecule was not detected on normal gastric epithelial cells. In few cases, carcinoma cells from large volumes of tumor located in the stomach showed detectable amounts of ICAM-1. On the other hand, all of the metastatic carcinoma cells from peritoneal effusions showed a high level of expression of the ICAM-1 molecule. The expression of ICAM-1 on adenocarcinoma cells was maintained and/or augmented by in vitro cultivation with tumor-infiltrating lymphocytes (TIL). Furthermore, two-color fluorescence-activated cell sorting analysis of TIL revealed that significant correlation was observed between the expression of ICAM-1 and the degree of TIL, composed mainly of CD3+ T cells including CD8+CD11b-, CD8+CD28+, CD8+S6F1+ and CD4+Leu8+, and CD57+CD16- and CD57+CD16+ NK cells, and HLA-DR+LeuM3+ macrophages.

Suppression by sorted CD8+CD11b- cells from T-cell growth factor-activated peripheral blood lymphocytes on cytolytic activity against tumour in patients with gastric carcinoma

To confirm the phenotypic characteristics of lymphokine-activated suppressor (LAS)effector cells, we isolated CD8+CD11b- and CD8-CD11b- cells from T-cell growth factor (TCGF)-activated peripheral blood lymphocytes (PBL) in 7 patients with gastric carcinoma (4 non-resectable and 3 resectable carcinoma) and 3 healthy controls. Sorted CD8+CD11b- cells from 3 of the patients with non-resectable carcinoma and from 1 of the patients with resectable carcinoma showed LAS cell activity. However, the LAS cell activity could not be observed in CD8+CD11b- cells from healthy controls. In addition, a sorted CD8-CD11b- subset of cells from both cancer patients and control did not express any suppressive activity. These facts clearly show that the cell populations responsible for suppression of cell-mediated antitumour immunity reside within CD8+CD11b- T-cells, at least in patients with advanced carcinoma.

Functional and phenotypic characteristics of recombinant interleukin-2 or T-cell growth factor-activated splenic lymphoid cells from patients with gastric or hepatocellular carcinoma

Fourteen days' culture of human spleen cells with recombinant interleukin-2 (rIL-2) or T-cell growth factor (TCGF) results in the generation of lymphokine-activated killer (LAK) effector cells that have the unique property of lysing natural killer (NK)-resistant human tumor cells, Daudi, and NK-sensitive K562 cells. LAK cells were generated from patients with advanced cancer or liver cirrhosis. The splenic LAK-effector cell types were analyzed by two-color flow cytometry. The rIL-2-induced LAK cells showed an increased proportion of CD8+CD11- and CD57+CD16- and a decreased proportion of CD4+Leu-8- cells. In contrast, TCGF-induced LAK cells revealed a significantly increased proportion of CD8+CD11- and CD4+Leu-8- cells and a decreased proportion of CD57+CD16- cells. Thus, splenic LAK cells with different surface phenotypes were induced by the cultivation with rIL-2 or TCGF. Furthermore, TCGF-induced LAK cell activities in patients with cancer were found to be lower than the rIL-2-induced LAK cell activities. It was noted that the TCGF-activated splenic lymphoid cells did not inhibit the effector process of tumor cell lysis by LAK cells that had been activated by rIL-2. Other mechanisms of lower LAK cell activities of TCGF-activated splenic lymphoid cells from patients with cancer were discussed. The findings suggest that spleens of examined patients with gastric or hepatocellular carcinoma do not seem to be responsible for suppression of cell-mediated antitumor immunity.

Generation and characterization of lymphokine-activated killer cells from non-Hodgkin's lymphoma patients

Lymphokine-activated killer cells generated from peripheral blood of Non-Hodgkin's lymphoma patients showed comparable levels of cytotoxicity. The patients with advanced disseminated disease displayed better augmentation with recombinant interleukin-2 (rIL-2) than the patients with localized disease. Thus, the defective cytotoxic potential of patients could be corrected in a culture of effector cells with IL-2. The indigenous ability to produce IL-2 in response to activation of peripheral blood mononuclear cells with phytohemagglutin showed slight depression and a positive correlation with the stage of the disease. Phenotypic analysis revealed a heterogenous population of cells involved in cytotoxic activity. Thus, IL-2 merits further evaluation in malignant lymphomas, particularly in relation to other variable therapies in conjunction with chemotherapy.