PURGING OF BONE MARROWS CONTAMINATED WITH MYELOID LEUKEMIC CELLS BY INTERLEUKIN-2 AND LYMPHOKINE-ACTIVATED KILLER CELLS

The capability of recombinant human interleukin-2 ( rhIL-2) and lymphokine-activated killer (LAK) cells in the purging of normal human bone marrows contaminated with human myeloid leukemic cell lines was evaluated. Mixtures of normal human bone marrow mononuclear cells ( BMC) and K562 cells or HL-60 cells (at the BMCK562 ratio of 200:1, 100:1 or 20:1) were incubated with IL-2 with or without LAK cells at the BMC:LAK ratio of 1:1 for one or three days. The nubmers of residual K562 cells, BFU-E and CFU-GM were examined by clonogenic assays. In 200:1 mixture groups without LAK cells, the number of K562 colonies reduced by 50% with no loss of BFU-E and CFU-GM in one-day cultures, and no K562 colonies formed in three-day cultures with about 20% loss of BFU-E and CFU-GM. If the BMC.K562 ratios were 100:1 or 20:1 in the mktures, the leukemic cells could not be eliminated. When the mixtures were incubated with IL-2 and LAK cells, no leukemic cell colonies were detected in the 20:1 group following one-day

TREATMENT OF PATIENTS WITH MALIGNANT PLEURAL EFFUSIONS DUE TO ADVANCED LUNG CANCER BY TRANSFER OF AUTOLOGOUS LAK CELLS COMBINED WITH rIL-2 OR rIL-2 ALONE

Experimental study both in vitro and in vivotogether with clinical trials showed that LAKcells have antitumor and antimetastatic effects(1-5)and that these effects are closely related tothe number of LAK cells transferred and the ad-ministration of rIL-2(1,6-8).Usually,autologousPBL’s are used as the source of LAK precursorsin the adoptive immunotherapy of cancer patients.But this not only puts an added burden on thecancer patient,it can cause serious side effectsas well(9).Although TIL’s may provide a solu-tion to this problem(10,11),their isolation fromsolid tumors is complex and consumes many rea-gents.We have reported that the isolation oflymphocytes from malignant ascites or from ma-lignant pleural effusions is not only simple

THE EFFECT OF PHENYLACETATE ON THE EXPANSION AND CYTOTOXIC ACTIVITY OF ADHERENT LAK CELLS FROM PATIENTS WITH HEPATOCELLULAR CARCINOMA

Objective: To improve the preparation of adherent lymphokine-activated killer (A-LAK) cells and study the synergistic anti-tumor effect of phenylacetate (PA) and A-LAK cells. Methods: A-LAK cells were obtained from peripheral blood mononuclear cells (PBMC) of patients with hepatocellular carcinoma (HCC) by using L-phenylalanine methyl ester (PME) to deplete immunosuppressive monocytes. The proliferation of SMMC7721 cell line treated with PA was studied. A-LAK cells were treated with the supernatant of SMMC7721 cells which had been pretreated with PA and the changes of the proliferation and anti-tumor activity of A-LAK cells were investigated. Results: The expansion of A-LAK cells was significantly higher than that of non-adherent LAK (NA-LAK) cells as well as regular LAK cells. The growth of SMMC7721 cells was significantly suppressed by PA. The supernatant of cultured tumor cells intensively suppressed the proliferation and cytotoxicity of A-LAK cells, but the suppressive effect of supernatant treated with PA previously was decreased. Conclusion: A-LAK cells could be simply prepared by using PME, and showed a synergistic anti-tumor effect with the combination of PA.

RESEARCHES ON THE ANTI-AUTOLOGOUS TUMOR EFFECTS OF HUMAN CANCER-KILLING CELLS IN NUDE MICE

An investigation of human splenic LAK cells killing autologous tumor in vivo has been performed in this study. Briefly, an ovary embryo carcinoma (OEC) removed surgically from patient was transplanted Into nude mice (s. c. ) and cultured in vitro, that would be used as targets. Lymphokine-activated killer (LAK) cells were generated from splenic lymphocytes of the OEC patient, who died two and half months after operation, by co- culture with recombinant human interleukin- 2 ( rIL- 2 ) in vitro. The results from Winn' s test in nude mice suggested that these LAK cells could effectively inhibit the tumorlgenicity of autologous tumor m vitro.

THE ULTRASTRUCTURAL OBSERVATION OF TARGET CELLS ATTACKED BY HUMAN LAK

In order to explore the killing mechanism of LAK, we observed the morphological change of K562 and Raji attacked by human LAK with transmission electron microscope, The result showed that 1 hour after coculture of LAK and target cell, target cell was significantly damaged.Part of target cells died via necrosis, and part via apoptosis. Our findings show that human LAK can kill target cells via necrosis and apoptosis simultaneously

Cytokine-induced killer cells showing multidrug resistance and remaining cytotoxic activity to tumor cells after transfected with mdr1 cDNA

Background Routine treatment of cancer such as surgery, radiation or chemotherapy is sometimes unable to erdiacate metastatic malignant cells. So we tried a new method and increased the adoptive immunotherapy of Cytokine-induced killer (CIK) cells in tumor patients and the multidrug resistance (mdr1) cDNA was transfected into CIK cells. Methods CIK cells were obtained from peripheral blood and induced by IFN-γ, anti-CD3 monoclonal antibody, IL-2 and IL-1. CIK cells were transfected with plasmid PHaMDR containing human mdr1 cDNA by electroporation. RT-PCR was used to detect mdr1 mRNA in transfected CIK cells. P-glycoprotein (P-gp) expressed on surface of CIK cells was assayed by FITC-conjugated anti-P-gp monoclonal antibody and flow cytometry. Multidrug resistance to doxorubicin and colchicine and cytotoxic activity to human breast cancer cell line MCF7 were performed using MTT method. Results mdr1 mRNA was detected in transfected CIK cells. P-gp was expressed on the surface of the transfected CIK cells, and the P-gp positive cells reached 21%-37% of the total CIK cells after transfection. The IC50 to doxorubicin increased to 22.3-45.8 times, and that to colchicines to 6.7-11.35 times, as compared to those of untransfected CIK cells. However, the cytotoxic activity to MCF7 cell line remained unaltered.Conclusions CIK cells were successfully transfected with mdr1 cDNA by using electroporation. The transfected CIK cells had the characteristics of multidrug resistance without change in their cytotoxic activity to tumor cells.