Human lymphokine-activated killer cell activity. Role of IL-2, IL-4, and IL-7.

The T-cell growth factors interleukin 2 (IL-2) and interleukin 7 (IL-7) induce lymphokine-activated killer (LAK) cell activity in short-term cultures of human peripheral blood mononuclear cells. Interleukin 4 (IL-4), another T-cell growth factor, induces LAK cell activity in IL-2-prestimulated lymphocytes only and inhibits LAK cell generation in normal peripheral blood mononuclear cells. Our studies of the processes involved using 21-mer phosphorothioate antisense oligonucleotides to the sequence adjacent to the start codon of IL-2 mRNA or IL-4 mRNA (effective concentration, 5 to 10 mumol/L) and cyclosporine (0.01 to 1.0 microgram/mL) or FK506 (0.01 to 1.0 ng/mL) demonstrate that IL-7-induced LAK cell activity is independent of IL-2 production and is regulated by endogenously generated IL-4. Like IL-2, IL-7 stimulated production of tumor necrosis factor alpha, but we failed to detect interferon gamma in IL-7-stimulated cultures. The implication of this regulatory feedback in IL-7-induced LAK cell generation for clinical applications is discussed.     

Lymphokine-activated killer (LAK) therapy for metastatic renal cell carcinoma]

Fifteen patients with metastatic renal cell carcinoma (RCC) were treated by administration of autologous lymphokine-activated killer (LAK) cells given together with systemic administration of interleukin-2 (IL-2). Pulmonary metastases alone were found in 10 cases, pulmonary and mediastinal nodal metastases in 3, and pulmonary and bone metastases in 2. LAK cells, generated by incubation in 700 units/ml of IL-2 for 3-4 days, were intravenously administered once a week. In addition, beginning on the day of the first LAK cell infusion, 3.5 x 10(5) units of IL-2 were intravenously infused once or twice a day with occasional supplementation of 3.5 x 10(5) units of IL-2 on each day of LAK cell infusion. The total number of LAK cells and total amount of IL-2 administered per patient in this study ranged from 0.8 x 10(10) to 6.9 x 10(10) cells and from 10.2 x 10(6) to 74.9 x 10(6) units, respectively. As toxic effects caused by the infusion of LAK cells, headache, shaking chills, fever and leukocytosis were found in all cases. Side effects possibly induced by IL-2 infusion were tolerable fever, fluid retention (body weight gain of 2-3 kg) and eosinophilia. Out of 15 patients, a partial response was observed in 4 patients who had pulmonary metastases alone. One of the 4 patients with a partial response was clinically free of disease after undergoing a thoracotomy for resection of residual lesions, but a brain metastasis was detected 10 months after the thoracotomy. The remaining 3 patients are being closely followed up at present.(ABSTRACT TRUNCATED AT 250 WORDS)     

Assessment of in vitro lymphokine activated killer (LAK) cell activity against renal cancer cell lines and its suppression by serum factor using crystal violet assay

Summary Lymphokine activated killer (LAK) cell activity against renal cancer cell lines was assessed in vitro using a crystal violet assay. A standard 4-h ⁵¹chromium release assay and a 48-h crystal violet assay showed that both natural killer-susceptible (NC65) and-resistant (ACHN) renal cancer cell lines were sensitive to LAK cells which had been generated by a 3-day incubation of peripheral blood mononuclear cells (PBMC) with recombinant interleukin 2 (rIL-2). Optimal LAK activity was generated by a 5-day culture of PBMC with 1 U rIL-2/ml. LAK activity was enhanced by the presence of IL-2 in the crystal violet assay system, while it was suppressed by fresh autologous serum. The suppressive effect was found in serum from both normal donors and patients with metastatic renal cell carcinoma, suggesting that non-specific suppressive factor(s) affecting LAK cell activity were present in human sera.     

Impairment of helper T-cell function and lymphokine-activated killer cytotoxicity following severe head injury.

Infection is a major complication of severe head injury, occurring in 50% to 75% of patients who survive to hospitalization. Previous investigations of immune activity following head injury have demonstrated suppression of helper T-cell activation. In this study, the in vitro production of interferon-gamma (INF-gamma), interleukin-1 (IL-1), and interleukin-2 (IL-2) was determined in 25 head-injured patients following incubation of peripheral blood lymphocytes (PBL's) with the lymphocyte mitogen phytohemagglutin (PHA). In order to elucidate the functional status of cellular cytotoxicity, lymphokine-activated killer (LAK) cell cytotoxicity assays were performed both prior to and following incubation of PBL's with IL-2 in five patients with severe head injury. The production of INF-gamma and IL-2 by PHA-stimulated PBL's was maximally depressed within 24 hours of injury (p less than 0.001 for INF-gamma, p = 0.035 for IL-2) and partially normalized within 21 days of injury. There was no change in the production of IL-1. When comparing the in vitro LAK cell cytotoxicity of PBL's from head-injured patients and normal subjects, there was a significant depression in LAK cell cytotoxicity both prior to (p = 0.010) and following (p less than 0.001) incubation of PBL's with IL-2. The results of this study indicate that IL-2 and INF-gamma production, normally required for inducing cell-mediated immunity, is suppressed following severe head injury. The failure of IL-2 to enhance LAK cell cytotoxicity suggest that factors other than decreased IL-2 production, such as inhibitory soluble mediators or suppressor lymphocytes, may be responsible for the reduction in cellular immune activity following severe head injury. These findings may have significant implications in designing clinical studies aimed at reducing the incidence of infection following severe head injury.     

Usefulness and limitation of immunotherapy of metastatic renal cell carcinoma with autologous lymphokine-activated killer cells and interleukin 2

Fourteen patients with metastatic renal cell carcinoma (RCC) were treated by systemic administration of autologous lymphokine-activated killer (LAK) cells and interleukin-2 (IL-2). Pulmonary metastases alone were found in 9 cases, pulmonary and mediastinal nodal metastases in 3, and pulmonary and bone metastases in 2. LAK cells, generated by incubation in 2 units/ml of IL 2 for 3-4 days, were intravenously administered once or twice a week. In addition, beginning on the day of the first LAK cell infusion, 1000 units of IL 2 diluted in normal saline were intravenously infused once or twice a day with occasional supplementation of 1000 units of IL-2 on each day of LAK cell infusion. The total number of LAK cells and total amount of IL-2 administered per patient in this study ranged from 0.8 x 10(10) to 6.9 x 10(10) cells and from 3.3 x 10(4) to 21.4 x 10(4) units, respectively. As toxic effects caused by the infusion of LAK cells, headache, shaking chills, fever and leukocytosis were found in all 14 cases. Side effects possibly induced by IL-2 infusion were tolerable fever, fluid retention (body weight gain of 2-3 kg) and eosinophilia. No objective regression of mediastinal nodal or bone metastases was observed. In regard to lung metastases, however, partial and minor responses were observed in 3 and 2 cases, respectively. One of the 3 patients with a partial response was clinically free of disease after undergoing a thoracotomy for resection of residual lesions, but a brain metastasis was detected 10 months after the thoracotomy. The remaining 2 patients are being closely followed up at present. In 3 of 11 patients who showed a minor response, no change or progressive disease, brain metastases were observed during or after the immunotherapy. Furthermore, we examined the possibility of selection of suitable candidates for this therapy on the basis of the degree of in vitro LAK activity against autologous cultured tumor cells in 6 patients, but there was no significant correlation between in vitro autologous tumor cell lysis by LAK cells and the clinical response to immunotherapy. In conclusion, although a complete response could not be obtained, it can be said that this immunotherapy may be effective against RCC, in particular lung metastases, since a partial response was achieved in 3 of 14 patients. However, it should be taken into consideration that this immunotherapeutic approach may have a risk of increasing the frequency of brain metastases.     

Identification and expansion of human lymphokine-activated killer cells: implications for the immunotherapy of cancer

Immunotherapy with lymphokine-activated killer (LAK) cells and interleukin 2 (IL-2) has been demonstrated to cause the regression of some human tumors. Expansion of peripheral blood lymphocytes (PBL) in recombinant or naturally produced IL-2, mitogens, and feeder cells results in a progressive expansion of cell number but a decline in lytic activity with time. Lytic activity for fresh tumor is best generated in IL-2 alone from specific purified subpopulations of lymphocytes. The precursor of the LAK cell has been isolated from a nonadherent, sheep erythrocyte receptor negative (E-) lymphocyte subpopulation by the selection of Leu 11+ and Leu 15+ cells by cell sorting. Separation resulted in a significant increase (P2 less than 0.05) in lytic activity against fresh tumor by the separated 11+15+ lymphocytes compared to the 11-/15- lymphocytes or PBL. Leu 11+/15+ lymphocytes could be expanded up to eightfold in IL-2 alone with maintenance of lytic activity. We identified two surface antigens on the LAK precursor cell, Leu 15 and Leu 11, and demonstrated a technique for obtaining purified populations of these cells. Purified and expanded LAK cells when administered to patients may have a role in increasing the potency and decreasing the toxicity associated with this therapy.     

CD3AK细胞过继治疗对肝癌患者T淋巴细胞亚群及功能活性的影响

目的 探讨CD3AK细胞过继治疗对原发性肝癌（PLC）患者T淋巴细胞亚群及功能活性的影响。方法 58例 PLC患者分为:CD3AK细胞治疗组（n=37）,对照组（n=21）,另取11例献血员为正常对照。治疗组术后第1天开始输注CD3AK细胞,每天1次,每次输注2x109个细胞,输注前30min静脉注射IL-2100u,连续5d为一个疗程;对照组只给予与治疗组相同的保肝治疗。观察两组T淋巴细胞亚群、IL-2R、细胞增殖功能、NK及LAK活性。结果 治疗组CD4/CD8比值、NK活性、LAK活性、IL-2R表达水平及细胞增殖活力与治疗前和对照组比较,差异均有显著性意义。结论 过继输注CD3AK细胞治疗能够补充肝癌患者有效抗肿瘤活性细胞数量的不足,并能够使T淋巴细胞亚群比例失调和功能低下的状况获得不同程度的改善。     

A case of multiple lung metastases and cervical lymph node metastasis of renal cell carcinoma failing to respond to interferon-alpha (IFN-alpha) but markedly responding to interleukin-2 (IL-2)

A 59-year-old man was admitted to our hospital with a left renal mass. A tumor was removed by radical nephrectomy and histological examination revealed renal cell carcinoma (pT2 N0 V1a). Two years later, CT scan showed multiple lung metastases. Despite treatment with recombinant IFN-alpha 2b, 5-FU, and MMC, the disease showed slow progression. About three years after the start of combination therapy, cervical lymph node metastasis appeared. Administration of interleukin-2 (IL-2) was attempted. Intravenous IL-2 therapy was started at a low daily dose of 35 x 10(4) JRU, and the daily dose was increased to 140 x 10(4) JRU. Because of side effect, the dose was subsequently decreased to 70 x 10(4) JRU three times per week. After 31 weeks of IL-2 therapy, his multiple lung metastases and cervical lymph node metastasis disappeared. The patient's natural killer cell (NK) activity and Lymphokine activated killer cell (LAK) activity were low before IL-2 therapy, but both NK activity and LAK activity showed a marked increase after IL-2 therapy started. Therefore, the tumor response to IL-2 was suggested to depend on NK activity and LAK activity.     

Study on adoptive immunotherapy with tumor-infiltrating lymphocytes (TIL) for renal cell carcinoma--amplification of IL-2-elicited TIL proliferation by OKT3-monoclonal antibody

Human autologous peripheral blood lymphocytes (PBL) and lymphocytes infiltrating renal cell carcinoma (TIL) were cultured with medium containing 1000 IU/ml of human interleukin 2 (IL-2). A high cytotoxic activity against fresh autologous as well as cultured allogenic tumor cells was developed. By culturing these lymphocytes with OKT3 monoclonal antibody during the initial 2 days of long-term culture, in terms of T cell activation signal, IL-2-driven lymphocyte proliferation was remarkably accelerated with maintenance of appreciable level of cytotoxic activity. The same culture method also induced an increase in OKT3 and IL-2 receptor positive lymphocyte population in LAK cells and TIL. This method may enable us to gain more autologous TIL in vitro for adoptive immunotherapy of renal cell carcinoma than the usual culture method with IL-2 alone. Five patients with metastatic renal cell carcinoma were treated with adoptive immunotherapy with TIL, LAK and IL-2. One patient with pulmonary metastasis has had a minor response which has lasted for 3 months so far. We have not experienced any serious side effects during the treatment.     

Toxicity and immunologic effects of continuous infusion of recombinant human interleukin-2 administered by selective hepatic perfusion in dogs.

A preclinical pilot study was done to evaluate the effects of a continuous regional hepatic arterial infusion of human recombinant interleukin-2 (IL-2) in dogs with an infusion pump. Preliminary studies demonstrated the ability to culture canine lymphokine-activated killer (LAK) cells in vitro and a canine LAK cell 15Cr assay was developed with a canine tumor cell line (CTAC) with appropriate controls. An in vitro study of the stability of IL-2 in the pump was done with a bioassay and enzyme-linked immunosorbent assay for IL-2 that demonstrated the stability of IL-2 during a 14-day period at 37 degrees C. Infusions of 300, 600, and 1200 units/kg/hr IL-2 were tested in vivo in dogs. LAK cell and natural killer cell activity, blood counts, and hepatic and renal function were monitored for 1 month. No significant natural killer or LAK response or toxicity was found at the 300 unit/kg/hr level. Infusion of 600 units/kg/hr was associated with a significant increase of the cytotoxic activity of peripheral blood lymphocytes after 3 weeks of treatment. At the 1200 unit/kg/hr level, increased activity occurred at 1 week and thereafter. The only significant toxicity was a 15% increase in body weight occurring during the infusion of 1200 units/kg/hr. Results of renal and hepatic function studies remained normal except for a slight elevation of transaminase levels after 4 weeks of 1200 units/kg/hr. A significant rise in eosinophil count was noted at each dosage level. Results of autopsies were unremarkable. These data demonstrate that continuous hepatic arterial regional infusion with relatively low doses of IL-2 is able to stimulate a sustained in vivo peripheral blood LAK cell effect in dogs with the absence of major side effects. These findings suggest that these methods may have both research application in large animals and clinical application in patients with tumors that are responsive to LAK cell lysis.     

Combined effect of interleukin 2 and bacillus Calmette-Guérin in the therapy of mice with transitional cell carcinoma.

We investigated the effect of combination therapy with interleukin 2 (IL-2) and Bacillus Calmette-Guérin (BCG) on C3H/HeN mice implanted with mouse bladder tumor cells (MBT2). MBT2-bearing mice were treated with a local injection of BCG into the tumor at a dose of 1 mg/day for a total of 3 times and/or a 10-day continuous subcutaneous infusion of 5 x 10(4) units IL-2/day from day 11 to day 20. As a result, the growth of the tumor in mice treated with IL-2 alone was slightly suppressed, while tumor growth was hardly suppressed in mice treated with BCG alone. However, when IL-2 was administered with BCG, tumor growth was strongly suppressed and mean survival time was prolonged. Natural killer cell activity in the spleen cells was most elevated in mice treated with IL-2 and BCG, while lymphokine-activated killer cell activity was not observed in all groups. Lymphocyte subset analysis showed that there was little change in the ratio of Lyt2-positive lymphocytes or that of L3T4-positive lymphocytes. These findings suggested that clinical evaluation of combination therapy with IL-2 and BCG may be worthwhile.     

Induction of cytotoxicity from human lymphocytes coated with bispecific antibody against human glioma cells

A bifunctional hetero-F (ab') 2 fragment containing the Fab portions from anti-CD3 and anti-glioma monoclonal antibodies was prepared. The antibody simultaneously recognized two different molecules, the CD3 complex on effector T cells and human glioma-associated antigens on target glioma cells. This bispecific F (ab') 2 fragment induced peripheral blood lymphocytes (PBLs) from healthy donors to lyse cells of the human glioma cell line, U251MG, that is resistant to natural killer cell-mediated cytolysis. Compared with lymphokine-activated killer (LAK) activity which is obtained by exposure to interleukin (IL)-2 for more than 3 days, the maximum bispecific antibody-dependent cytotoxicity can be generated only after 24 hour exposure to IL-2. And cytotoxicity of lymphocytes triggered by the bispecific antibody was dependent upon the concentration of IL-2 in the culture medium. The effect of the bispecific antibody on LAK cells was tested in patients suffering from malignant glioma. One patient who received specific targeting therapy (LAK plus bispecific antibody) showed the disappearance of high density tumor mass from CT scan. But the patient who received only LAK therapy showed the recurrence of tumor one year after LAK treatment. These are preliminary data, but may be a promising approach in cancer immunotherapy.     

In vitro killing of human glioblastoma by interleukin-2-activated autologous lymphocytes

Culture of peripheral blood lymphocytes (PBL) from brain-tumor patients with recombinant interleukin-2 (IL-2) results in the activation of lymphokine-activated killer cells (LAK) with the capacity to lyse autologous and allogeneic glioblastoma. In this study, PBL obtained from brain-tumor patients were cultured with or without IL-2 for 3 to 7 days and then tested for their ability to lyse target cells in a 4-hour chromium release cytotoxicity assay. The PBL were drawn 1 to 2 weeks following operative tumor debulking. Cells used as targets included fresh brain-tumor cells obtained at the time of craniotomy, fresh brain-tumor cells grown from 1 to 3 weeks in tissue culture, fresh autologous PBL, and allogeneic glioblastoma cells grown in tissue culture. Peripheral blood lymphocytes from brain-tumor patients that were cultured without IL-2 did not significantly lyse autologous or allogeneic glioblastoma. However, when these PBL were cultured with IL-2, LAK were generated which produced marked lysis of autologous as well as allogeneic tissue-culture glioblastoma in all of eight cases. Significant lysis of autologous fresh tumor by patient LAK was observed in four of five experiments. By contrast, patient LAK did not kill autologous normal PBL. The ability to generate LAK was not influenced by the patient's age, previous therapy, or the administration of steroids.     

Long-term follow-up of patients with recurrent malignant gliomas treated with adjuvant adoptive immunotherapy

Between August 1986 and October 1987, the Denver Brain Tumor Research Group conducted a clinical trial using autologous human recombinant interleukin-2 (rIL-2)-activated lymphocytes to treat 20 patients with recurrent high-grade gliomas. The trial involved surgical resection and/or decompression followed by intracavitary implantation of lymphokine-activated killer (LAK) cells and autologous stimulated lymphocytes (ASL) along with rIL-2 in a plasma clot. One month later, stimulated lymphocytes and rIL-2 were infused through a Rickham reservoir attached to a catheter directed into the tumor bed. The LAK cells were rIL-2-activated peripheral blood lymphocytes cultured for 4 days; the ASL were lectin- and rIL-2-activated peripheral blood lymphocytes cultured for 10 days. Of the 20 patients treated, 11 were evaluated as a group (mean age, 44 years, range, 15-61 years; mean Karnofsky rating, 69, range, 50-100; mean Decadron dose at entry, 14 mg/d, range, 0-32). The average number of lymphocytes implanted was 7.6 x 10(9) (range, 1.9-27.5 x 10(9], together with 1 to 4 x 10(6) U of rIL-2. To date, 10 of the 11 patients died, all from recurrent tumor growth. The median overall survival time was 63 weeks (range, 36-201; mean, 86). The median survival time after immunotherapy was 18 weeks (range, 11-151; mean, 39). No significant difference in survival after immunotherapy was found between those patients who had received previous chemotherapy and those who had not. The use of steroids or prior chemotherapy did not influence the in vitro generation of ASL or LAK cells.(ABSTRACT TRUNCATED AT 250 WORDS)     

Influence of PGE2- and cAMP-modulating agents on human glioblastoma cell killing by interleukin-2-activated lymphocytes

Human glioblastoma cells secrete factors, such as prostaglandin E (PGE) and transforming growth factor beta type 2, which are capable of suppressing several immune functions. The present study investigated the effect of PGE2 and agents known to increase intracellular cyclic adenosine monophosphate (cAMP) levels on 1) the induction of lymphokine-activated killer (LAK) cell activity from the peripheral blood lymphocytes (PBL) of both normal and glioma patients and on 2) the cytolytic activities of tumor-infiltrating lymphocytes (TIL's) isolated from malignant gliomas after expansion in vitro with interleukin-2 (IL-2). Cytolytic activity was measured against autologous and allogeneic tumor cells and the natural killer-resistant Daudi cell line. The results demonstrate that PGE2 and agents known to increase intracellular cAMP levels can significantly suppress the IL-2-dependent generation of cytolytic activity from the PBL of normal and glioma patients and from glioblastoma-derived TIL's. The inhibitory effects of these agents could not be reduced by higher concentrations of IL-2 or by cyclic guanosine monophosphate. Although the suppressive effect of PGE2 was most significant during the early stages of LAK cell generation, an inhibitory effect was still evident when PGE2 was added directly to the cytotoxicity assay. Secretion of PGE2 by glioblastoma cells in vivo may regulate both the generation of an immune response and the effectiveness of adoptively transferred immune cells.     

Augmentation of lymphokine-activated killer cell activity in patients with gastrointestinal cancer

Adoptive cellular immunotherapy with lymphokine-(interleukin 2) activated killer (LAK) cells is not as successful in patients with gastrointestinal cancer as with other tumour types. This may be because the cytotoxic capacity of LAK cells from such patients is suboptimal. In this study we have sought to augment this activity by stimulating the lymphocytes with recombinant human interferon-gamma (r-HuIFN-gamma) in addition to interleukin 2 or by depleting the lymphocytes of adherent suppressive mononuclear cells. Both procedures augment LAK activity in gastrointestinal cancer patients but adherent cell depletion results in fewer cells being available for adoptive cellular immunotherapy. No further augmentation of LAK activity of adherent cell depleted cells could be accomplished by addition of r-HuIFN-gamma. Co-stimulation of unfractionated peripheral lymphocytes with r-HuIFN-gamma is the preferable procedure for the generation of LAK cells for adoptive cellular immunotherapy in patients suffering from gastrointestinal cancer.     

Derivation of cells with lytic activity against fresh and cultured tumors from human bone marrow

We studied the derivation of cells with lymphokine-activated killer (LAK) cell activity from human bone marrow cultures. In these experiments, 26/26 specimens of human bone marrow obtained from sternum, iliac crest, rib, and humerus cultured with IL-2 (1000 U/cc) under varying conditions were able to generate LAK activity. LAK activity obtained from bone marrow mononuclear cell cultures (BMMC) was observed only with exposure to IL-2. Peak LAK activity against fresh melanomas and renal cell carcinoma and sarcomas was obtained usually by the second or third week in culture and could be maintained in some instances for greater than 28 days. Parallel experiments comparing autologous peripheral blood lymphocytes (PBL) cultured under identical conditions and tested simultaneously with BMMC demonstrated comparable LAK activity. T-cell depletion using sheep red blood cell rosetting and density separation on discontinuous gradients did not significantly enrich for a population with enhanced LAK activity. The use of irradiated Epstein-Barr virus-B-cell feeder lines significantly enhanced generation of LAK activity from BMMC when compared to controls (P less than 0.006). Conditioned media from PHA-stimulated 2-day and 4-day PBL cultures, 4-day mixed lymphocyte cultures, and 3-day LAK cultures did not consistently increase the growth or lytic activity of BMMC cultures grown in the presence of IL-2 (1000 U/cc). Phenotypic analysis of BMMC cultures after culture with IL-2 with lytic activity revealed mixed populations with mature T cells (CD3) and null cells (CD2+/CD4- and Leu 19+/Leu 7+) with decreased myeloid precursors (My 9+).     

Interleukin-2 and autologous lymphokine-activated killer cells in the treatment of malignant glioma. Preliminary report

Nine patients with malignant glioma were treated with the lymphokine interleukin-2 (IL-2) or with lymphokine-activated killer (LAK) cells, and one patient received combination therapy with both LAK cells and IL-2. The LAK cells were generated by culturing recombinant IL-2 with peripheral blood lymphocytes obtained from brain-tumor patients. Escalating doses of LAK cells (10(8) to 10(10] or IL-2 (10(4) to 10(6) U) were administered intraoperatively by direct injection into the brain tissue surrounding the cavity left by debulking the tumor. There were no signs of systemic or neural toxicity following treatment. The selective killing of the tumor by LAK cells used for these treatments was demonstrated by a chromium release microcytotoxicity assay which showed in vitro the ability of the LAK cells to lyse glioma cells but not normal cells.     

The mechanism of IL-2-mediated protection against GVHD in mice. II. Protection occurs independently of NK/LAK cells.

We have recently demonstrated that high-dose IL-2, when begun on the day of bone marrow transplantation, has a potent protective effect against graft-vs.-host disease mortality, especially when coadministered with T cell-depleted syngeneic bone marrow cells. Because several groups of investigators have demonstrated that lymphokine-activated killer cells can mediate GVHD protection, we hypothesized that the mechanism of protection by IL-2 administration might involve the in vivo activation of natural killer and/or LAK cells. In order to test this hypothesis, we evaluated the effect of IL-2 administration on the number of NK1+ cells and on NK-mediated cytotoxic activity in recipients of GVHD-producing inocula. Furthermore, we evaluated the effects on IL-2-induced GVHD protection of depleting NK cells and LAK precursor cells in vivo with mAb against NK1.1 or antiserum against asialo GM1. The results demonstrate that: (1) The number of NK1+ cells is not increased in spleens of IL-2-treated compared with control recipients of GVHD-producing inocula; (2) NK activity is not increased in IL-2-treated compared with control recipients of GVHD-producing inocula during or immediately following the period of IL-2 administration; (3) depletion of NK cells and LAK precursors from the donor and host influenced the time course of GVHD-related mortality in a complex fashion; and (4) IL-2-induced GVHD protection is largely independent of the activity of an NK or LAK cell population of donor or host origin. IL-2-induced GVHD protection therefore reflects primarily the activity of non-LAK protective cell populations, or it may be a direct inhibitory effect on responding donor cell populations as they encounter host antigen.     

Induction of LAK cells and CTL in patients with brain tumor and research of its clinical application

We studied whether lymphokine-activated killer (LAK) cells and cytotoxic T lymphocytes (CTL) were capable of being induced in vitro from peripheral blood lymphocytes of patients with brain tumor. The LAK cells were generated by culturing recombinant IL-2 with peripheral blood lymphocytes. The culture was continued for 72 hours; then cytotoxicity to Hela cell was examined by 4-hr 51Cr release assay. LAK cells were induced from lymphocytes of patients with brain tumor, but the cytotoxicity was rather less than that of healthy subjects, and it was accompanied by clinical deterioration. CTL was generated by co-culture of patient's peripheral blood lymphocytes and autologous brain tumor cells with addition of rIL-2. The cytotoxicity to autologous and allogenic brain tumor cells was examined by 16-hr51Cr release assay. The cytotoxicity to autologous tumor was approximately 30-40%, and there was cross reaction to allogenic tumor cells. The adoptive transfer of CTL to four patients was performed. One patient improved clinically, and on CT scan, growth of the tumor appeared to have been reduced.