Adoptive immunotherapy of a rat glioma using lymphokine-activated killer cells and interleukin 2

The aim of the present study was to develop an animal model to test the therapeutic potential of purified adherent lymphokine-activated killer (A-LAK) cells against an intracerebrally implanted rat glioma, designated F98. Highly purified A-LAK cells demonstrated greater activity against F98 tumor cells than conventional lymphokine-activated killer cells, as determined by means of 51Cr-release and clonogenic assays. Therapeutic efficacy was evaluated by means of a Winn neutralization assay, in which F98 targets and A-LAK cells or control nonadherent mononuclear cells were incubated for 18 h in vitro and then implanted stereotactically into the right caudate nuclei of Fischer rats. Animals given injections of 4000 F98 cells alone or control nonadherent mononuclear cells had a mean survival time of 22.3 days, compared to 46.1 days (P less than 0.001) for rats treated with A-LAK cells. Increasing the tumor inoculum to 12,500 cells reduced the survival time of A-LAK-treated animals to 27.8 days, compared to 20.8 days for untreated controls. Systemic administration of 50,000 units/kg of interleukin 2 every 12 h for 5 days failed to improve survival. The mean survival time of rats implanted with the F98 tumor ranged from 16 days for 10(5) cells to 29 days for 10(2) cells. Extrapolating from these survival data, treatment with A-LAK cells may have decreased the number of F98 cells to less than 10, but even this small number was still lethal. Supernatants from F98 cells had immunoinhibitory activity that, further, may have modulated the antitumor effects of A-LAK cells. Our results indicate that curative, adoptive immunotherapy of the F98 glioma by means of A-LAK/interleukin 2 is impossible to achieve and provide some explanation for the clinical failures that have been observed in the adoptive immunotherapy of malignant gliomas.     

Successful immunotherapy of murine experimental hepatic metastases with lymphokine-activated killer cells and recombinant interleukin 2

Lymphokine-activated killer (LAK) cells are generated in vitro by the incubation of normal murine splenocytes in interleukin 2. We have shown previously that the systemic injection of LAK cells in conjunction with recombinant interleukin 2 can reduce the number of established pulmonary metastases in mice. In an attempt to study this approach in the treatment of hepatic metastases, we developed a technique for the induction of hepatic metastases in mice based on the intrasplenic injection of tumor cells and have tested the effects of LAK cells and recombinant interleukin 2 produced in Escherichia coli (RIL-2) therapy on these metastases. Treatment with LAK cells alone in 14 consecutive experiments rarely produced significant reduction in metastases over control (mean percentage reduction, 12%). Therapy with RIL-2 alone produced a dose-dependent reduction in the number of liver metastases. In 20 consecutive experiments when RIL-2 was administered i.p. three times a day at doses varying from 1,000 to 5,000, 10,000 to 15,000, and 25,000 units, a statistically significant (P less than 0.05) reduction in liver metastases was seen in 2 of 12, 2 of 4, and 8 of 12 determinations, respectively (percentage reduction, 0 to 97; mean, 42%). At doses greater than 25,000 units, the reduction in metastases was highly reproducible (percentage reduction, 66 to 95; mean, 83%) and was statistically significant in 14 of 14 determinations. When LAK cells were given i.v. in addition to RIL-2 administration in 16 consecutive experiments, the percentage reduction in liver metastases was markedly increased over that seen with RIL-2 alone (mean percentage reduction, 77% at doses of 5,000 to 25,000 units of RIL-2 and mean reduction, 97% for doses greater than 25,000 units of RIL-2). At doses of 5,000, 10,000, 25,000, and greater than 25,000 units of RIL-2 plus LAK cells, significant reduction of liver metastases (P less than 0.05) was achieved in 3 of 7, 2 of 2, 8 of 8, and 6 of 6 determinations, respectively. When animals were given fresh splenocytes or splenocytes cultured in complete medium without RIL-2 instead of LAK cells, no reduction in liver metastases was seen except for that attributable to the administration of RIL-2 alone. Sublethal total body irradiation of the mice prior to therapy abrogated the therapeutic effects of RIL-2, but the effects of treatment with LAK cells plus RIL-2 were maintained. Thus, treatment with RIL-2 alone or in combination with LAK cells is effective in reducing the number of established hepatic micrometastases in a murine model.(ABSTRACT TRUNCATED AT 400 WORDS)     

Cytolytic potential of peripheral blood T-lymphocytes following adoptive immunotherapy with lymphokine-activated killer cells and low-dose interleukin 2

In this study, we investigated the cytolytic activity of peripheral blood T-cells (PBT) obtained from nine patients with primary lung cancer treated by surgical adjuvant adoptive immunotherapy (AIT) with lymphokine-activated killer cells and low-dose recombinant interleukin 2 at the time of rebound lymphocytosis (24-48 h after AIT). In eight of nine patients, nonspecific cytotoxicity of peripheral blood lymphocytes significantly increased as compared with that of pre-AIT peripheral blood lymphocytes. However, purified PBT showed much less activity to kill tumor cells although they increased in number and were activated well in terms of increases in the expression of HLA-DR and interleukin 2 receptor. The cytolytic activity of post-AIT PBT was significantly enhanced when they were targeted to Fc receptor-bearing tumor cells (K562 or Daudi) with anti-CD3 (NU-T3) or anti-T-cell receptor (TCR)alpha beta (WT31) monoclonal antibody in all five patients examined. Phenotypically, the targeted cytotoxicity was predominantly mediated by CD8+ cells. The results indicated that in vivo-activated PBT by AIT could not exhibit direct cytotoxicity, but they acquired cytolytic potential, the effect of which was expressed by targeting to tumor cells.     

Synergy of human recombinant interleukin 1 with interleukin 2 in the generation of lymphokine-activated killer cells

Peripheral blood mononuclear cells cultured in vitro with interleukin 2 (IL-2) become cytolytic towards both autologous and allogeneic tumor cells. We report here that IL-1 synergizes with IL-2 in serum-free conditions to produce increased (1.3-286-fold) lymphokine-activated killer (LAK) activity. The most dramatic synergy is seen with low IL-2 concentrations (10 U/ml, 222 pM) and 50-250 U/ml IL-1 alpha or beta. Kinetics of addition experiments demonstrate a specific requirement for IL-1 at or before addition of IL-2 to the culture. We postulate that one of the mechanisms whereby IL-1 augments LAK activity is by rendering LAK-precursors more responsive to IL-2. Up-regulation of the IL-2 receptor beta chain (Tac) and increased [3H]thymidine incorporation in cultures containing IL-1 and IL-2 support this view. In some instances, IL-1 alone is capable of maintaining/generating a small degree of cytolytic activity. Collectively, our data demonstrate that IL-1 is capable of interacting with low dose IL-2 to significantly augment LAK activity, potentially playing an important role in the early stages of LAK activation and differentiation. Because synergy is observed with dramatically reduced IL-2 concentrations, this system may offer an alternative approach to high dose IL-2 therapy for the treatment of neoplastic disease.     

Adoptive immunotherapy for recurrent glioblastoma multiforme using lymphokine activated killer cells and recombinant interleukin-2

Thirteen patients with recurrent glioblastoma were treated with adoptively transferred autologous lymphokine activated killer (LAK) cells and recombinant interleukin-2 (rIL-2). Patients' blood mononuclear cells (MNC) obtained by leukapheresis were cultured at 2.5 million MNC per ml for 3 to 5 days in media containing 1000 U rIL-2/ml. After incubation, the nonadherent MNC from all cultures (0.5-5 X 10(9] were combined and concentrated for infusion in 5 to 10 ml saline containing 10(6) U rIL-2. Nine patients received one injection of LAK cells and rIL-2 into the brain tissue immediately surrounding the tumor cavity during craniotomy for subtotal tumor removal (Group 1). On each of the 3 days after surgery, patients received boosters of 10(6) U rIL-2 delivered into the tumor cavity through a skin flap or via an Ommaya reservoir. Approximately 1 to 2 weeks after this series of injections, these patients were treated with a second cycle of LAK cells and rIL-2 injected into the tumor cavity using the reservoir. Four patients received both adoptive immunotherapy cycles by intracavitary injection (Group 2). In this relatively small patient pool, neither age, sex, Karnofsky score, treatment history, nor anticonvulsant and steroid dosage appeared to influence a patient's ability to make LAK cells. The therapy, itself, was well-tolerated by all patients although they all displayed symptoms of aseptic meningitis and increased intracranial pressure, i.e., headache, fever, malaise on the days of LAK cell and/or rIL-2 infusion. The therapy did not appear to have a significant impact on patient survival (mean, 30 weeks) especially for those patients with a high postsurgical tumor burden. As the therapy is safe, the authors believe its efficacy can best be tested in patients with a newly diagnosed or recurrent glioblastoma which lies in an area where a near-total resection is possible.     

Adoptive immunotherapy using lymphokine-activated killer (LAK) cells and interleukin-2 for recurrent malignant primary brain tumors

Summary Ten patients with recurrent malignant primary brain neoplasms were treated with adoptive immunotherapy using lymphokine-activated killer (LAK) cells and interleukin-2 (IL-2). Nine patients had supratentorial glioma and they received multiple intratumoral instillations of LAK cells through reservoir-catheter system or burrhole. The other patients with disseminated subarachnoid metastases from posterior fossa medulloblastoma received immunotherapy via lumbar subarachnoid route. A partial and transient clinical response was observed in two patients following the therapy, and a cystic transformation of the essentially solid tumor was noted on the CT scans of these two patients. No significant clinical or radiological response to the treatment was observed in the remaining 8 patients. The results of this preliminary study reveal limitations of the regional intratumoral adoptive immunotherapy using currently available techniques and provide sufficient evidence of its effectiveness to warrant further investigations.     

Local adoptive immunotherapy of human head and neck cancer xenografts in nude mice with lymphokine-activated killer cells and interleukin 2

The efficacy of local adoptive immunotherapy with human lymphokine-activated killer cells and recombinant interleukin 2 (rIL-2) in growth inhibition of established squamous cell carcinoma of the head and neck (SCCHN) was evaluated in a nude mouse model. The model of xenografted SCCHN was established by s.c. injections of in vitro maintained tumor cells (2-10 x 10(6) cells/mouse) into the flank of splenectomized animals pretreated with cyclophosphamide (200 mg/kg). The SCCHN line used was tumorigenic in 95% of the appropriately conditioned nude mice. Inhibition of tumor growth by locally administered effector cells was the end point of the study, since the tumors did not metastasize within 6 weeks of tumor challenge. Either i.p. or local administration of rIL-2 alone (1000 units/day) to the tumor site daily for 2 weeks resulted in a significant inhibition of tumor growth. In the absence of detectable natural killer activity in these mice, a modest dose of rIL-2 had a direct antitumor effect on SCCHN cells in vivo. In addition, complete inhibition of tumor growth was achieved with 3 times weekly injections of 5-10 x 10(6) lymphokine-activated killer cells delivered to the tumor site and 1000 units of rIL-2 administered locally every day for 2 weeks. Our data indicate that local or systemic immunotherapy with rIL-2 alone or local adoptive immunotherapy with an adequate dose of lymphokine-activated killer cells plus rIL-2 may be effective in preventing the growth of established SCCHN tumors in vivo.     

Circulating cytokines in patients with metastatic cancer treated with recombinant interleukin 2 and lymphokine-activated killer cells

Treatment with recombinant interleukin 2 and lymphokine-activated killer cells (rIL-2/LAK) has produced a clinical antitumor effect in preliminary human trials. The cytokines gamma-interferon (IFN-gamma), tumor necrosis factor alpha (TNF-alpha), and tumor necrosis factor beta (TNF-beta, lymphotoxin) have potent in vitro antitumor activity and some clinical toxicities similar to interleukin 2 (IL-2)/LAK. This study sought to determine whether these cytokines were detectable in sera of IL-2/LAK-treated patients. Ten patients were treated with a protocol of 5-day i.v. rIL-2 bolus priming (10(5) units/kg, every 8 h), followed by 5 daily phereses with harvested lymphocytes cultured in vitro to generate LAK, and 5 days of rIL-2 bolus with infusion of LAK cells. Five patients were treated with a protocol modified to a 3-day rIL-2 prime and 6-day continuous infusion rIL-2 (3 x 10(6) units/m2/day) with infusion of LAK cells. Serum specimens were obtained prior to and 0.5, 2, 3, and 5 h after IL-2 or LAK cell administrations. IFN-gamma was detected by enzyme-linked immunosorbent assay, TNF-alpha by WEHI 164 bioassay or enzyme-linked immunosorbent assay, and TNF-beta by WEHI 164 cell bioassay. During the prime, few patients manifested in vivo detectable serum cytokines: IFN-gamma, three of ten, 5-day prime (1.03 +/- 0.46 ng/ml), and zero of five, 3-day prime; TNF-alpha, one of ten, 5-day prime, and one of three, 3-day prime; TNF-beta, one of ten, 5-day prime. The supernatants of in vitro LAK generation cultures had detectable levels of cytokines at 24 h which increased progressively until culture harvest at Day 4 (IFN-gamma, 2.56 +/- 0.34 ng/ml; TNF-alpha, 356 +/- 110 pg/ml; TNF-beta, 8.2 +/- 4.4 units/ml). The highest levels of in vivo serum cytokines occurred following LAK cell infusion and were more often elevated in patients receiving rIL-2 by bolus than by continuous infusion: IFN-gamma, four of six bolus, zero of three continuous infusion; TNF-alpha, six of six bolus (maximum 679 pg/ml) versus two of three continuous infusion (maximum, 106 pg/ml). LAK cells in vitro responded with cytokine release on stimulation by tumor cell lines (IFN-gamma, 0.88 +/- 0.06 ng/ml; TNF-alpha, 426 +/- 16 pg/ml; TNF-beta, 0.64 +/- 0.06 units/ml). In summary, this preliminary study has detected circulating cytokines in sera of patients receiving IL-2/LAK therapy. The greatest cytokine elevations followed LAK cell infusion.(ABSTRACT TRUNCATED AT 400 WORDS)     

Effect of immunotherapy with allogeneic lymphokine-activated killer cells and recombinant interleukin 2 on established pulmonary and hepatic metastases in mice

The adoptive transfer of lymphokine-activated killer (LAK) cells in conjunction with the systemic administration of recombinant interleukin 2 (RIL-2) results in the regression of established pulmonary and hepatic micrometastases from a variety of immunogenic and nonimmunogenic murine tumors in syngeneic C57BL/6 mice. Recent studies have shown that this therapeutic approach can mediate the regression of cancer in humans as well. Because of the practical difficulties in obtaining syngeneic or autologous LAK cells for the therapy of cancer in humans we have now evaluated the antitumor efficacy of allogeneic LAK cells generated from different strains of mice. The in vitro lysis of fresh tumor targets by LAK cells is not a major histocompatibility complex-restricted phenomenon since LAK cells of BALB/c-H-2d, DBA/2-H-2d, and C3H-H-2k origin all exhibited lytic activity when tested against allogeneic MCA-102-H-2b tumor cells in short term 51Cr release assays. In vivo, the i.v. transfer of allogeneic LAK cells combined with i.p. injections of RIL-2 reduced the number of established pulmonary metastases induced by either MCA-105 or MCA-101 tumors which are syngeneic to C57BL/6 hosts. The extent of reduction of these pulmonary metastases by the allogeneic LAK cells was directly dependent upon the dose of RIL-2 given; increasing doses of systemically administered RIL-2 resulted in increasingly greater reduction in the numbers of established 3-day pulmonary sarcoma metastases. In dose titration experiments, adoptive transfer of at least 2 doses of 10(8) allogeneic LAK cells was necessary to achieve significant antitumor effect in vivo. Allogeneic LAK cells were also successful in mediating significant regression of hepatic micrometastases. Again, the i.v. transfer of allogeneic LAK cells had a smaller therapeutic benefit compared to i.v. transfer of syngeneic LAK cells. When allogeneic LAK cells were injected intraportally, however, they were as effective as syngeneic LAK cells. Allogeneic LAK cells had little, if any, therapeutic effect on established pulmonary and hepatic metastases when administered to recipients previously immunized to the histocompatibility antigens on the donor cells. Taken together, our results indicate that allogeneic LAK cells from several strains of mice are effective in lysing fresh MCA-102 tumor in vitro and that when given i.v. in sufficient numbers, in conjunction with RIL-2, they can mediate significant reduction in the number of established pulmonary and hepatic micrometastases in nonalloimmunized C57BL/6 mice.(ABSTRACT TRUNCATED AT 400 WORDS)     

The requirements for successful immunotherapy of intraperitoneal cancer using interleukin-2 and lymphokine-activated killer cells

In a significant proportion of patients with gastrointestinal and ovarian malignancy the peritoneal cavity is a prominent site at which surgical treatment fails. Adjuvant treatments directed at this site should be investigated in an attempt to improve survival in patients with these cancers. In the study reported here, a model of intraperitoneal tumor in the mouse was established and shows the effectiveness of lymphokine activated killer (LAK) cells and exogenous interleukin-2 (IL-2) in the control of intraperitoneal tumor. A standard regimen was used to treat seven different tumors in three different mouse strains. In all seven cases a significant reduction in the intraperitoneal tumor mass was observed when LAK cells plus IL-2 were used as immunotherapy. A prolonged survival was also demonstrated in mice with intraperitoneal tumor. The relevance of these observations to patients with cancer was demonstrated in that allogeneic and syngeneic LAK cells were equally effective, LAK cells generated from normal and from tumor-bearing donors showed equal reactivity, and this treatment was successful in the immuno-compromised host. Both IL-2 derived from an IL-2-producing subline of the EL-4 thymoma and recombinant IL-2 were equally effective in the control of intraperitoneal tumor. The local-regional effects of the intraperitoneal administration of IL-2 were demonstrated by high levels of LAK cell cytotoxicity in peritoneal exudate cells. Intraperitoneal IL-2 or IL-2 plus LAK cell regimens should be investigated in the treatment of malignancy that spreads by implantation onto peritoneal surfaces.     

Laboratory correlates of adoptive immunotherapy with recombinant interleukin-2 and lymphokine-activated killer cells in humans

Adoptive immunotherapy with interleukin 2 (IL-2) and lymphokine-activated killer (LAK) cells (IL-2/LAK) is a technically demanding cancer therapy dependent upon large scale isolation and culture of lymphocytes. An important question is whether this technology can be accomplished routinely outside of highly specialized centers. In addition, no systematic examination of laboratory correlates of IL-2/LAK therapy in humans has been reported to date. The objectives of this report are to address two issues relevant to IL-2/LAK therapy. (a) Can IL-2/LAK therapy be accomplished outside of previously identified centers of expertise? (b) What are the relevant laboratory/clinical parameter correlations? The six institutions in the National Cancer Institute extramural trial treated 83 evaluable patients with renal cancer, malignant melanoma, or colon cancer with IL-2/LAK by a uniform protocol. Patients received 5 days of IL-2 priming, then daily leukaphereses for 5 days starting 48 h after IL-2 to harvest cells. Mononuclear cells were isolated, then cultured in roller bottles in 1-liter aliquots for 3 to 4 days at a cell density of 1.5 x 10(6) per ml with recombinant IL-2, 1500 units per ml. Cells were harvested and administered to patients with additional IL-2. Administration of IL-2 regularly induced lymphopenia and rebound lymphocytosis. Leukapheresis yields and numbers of LAK cells generated in culture and reinfused into patients correlated directly with peak lymphocyte counts achieved by IL-2 administration. Mean mononuclear cell recovery per 5 days of leukapheresis (+/- SEM) was 14.3 +/- 0.8 x 10(10). Average volume of cells cultured per patient was 95 liters (range, 41 to 235). Mean yield of cells harvested from cultures was 53%. Mean total number of LAK cells infused per patient was 7.6 +/- 0.4 x 10(10) (range, 2 to 15.2 x 10(10]. LAK activity was measured in vitro by lysis of 51Cr-labeled natural killer-resistant Daudi and fresh tumor targets. LAK effector cells regularly lysed these targets in vitro. Neither tumor reduction nor clinical toxicity correlated with dose or with cytolytic activity of LAK cells, or with other laboratory parameters including base-line lymphocyte count and IL-2-induced lymphocytosis. We conclude: (a) large quantities of LAK effector cells with tumoricidal activity can be generated routinely at different centers; (b) neither in vitro LAK activity nor numbers of LAK cells infused were predictive of clinical efficacy or toxicity. There is a need to identify other laboratory or clinical parameters more predictive of IL-2/LAK therapeutic efficacy or toxicity.     

Generation of human lymphokine-activated killer cells following brief exposure to high dose interleukin 2

Current laboratory lymphokine-activated killer (LAK) cell activation procedures require culture of peripheral blood mononuclear cells (PBMC) in the presence of 1000-1500 units/ml of interleukin 2 (IL-2) for 3-7 days. However, we have observed that a brief exposure (15 min-1 h) of PBMC to a high concentration of IL-2 results in the maturation of LAK precursor cells to cytolytic effector cells over the course of 1-3 days. These IL-2-pulsed LAK cells express cytolytic activity comparable to that of nonpulsed PBMC (cultured continuously in IL-2) at 3 days of culture. The acquisition of cytolytic activity followed the same kinetics for both pulsed and nonpulsed mononuclear cells and was maintained when tested at day 7. The pulsed LAK cells were capable of significantly lysing 11 different tumor targets tested and flow cytometric analysis revealed that pulsed LAK cells were phenotypically similar to nonpulsed LAK cells. Serum obtained from cancer patients undergoing IL-2/LAK cell therapy did not inhibit the maturation of the pulsed mononuclear cells into LAK cells. Interestingly, only PBMC obtained from cancer patients receiving in vivo IL-2 infusions could be induced to generate the same levels of cytolytic activity as those in nonpulsed cells using this pulse procedure. PBMC obtained from healthy, normal donors could not be pulsed to the same levels of activation as nonpulsed LAK cultures. Our study demonstrates that for the generation of maximum LAK cell cytolytic activity, LAK cell precursors must be primed in vivo with IL-2. Implementation of this procedure could eliminate the high cost of cell culture which normally accompanies IL-2/LAK cell therapy. Such an approach could make IL-2/LAK cell therapy more accessible for cancer patients.     

Severe hypovitaminosis C occurring as the result of adoptive immunotherapy with high-dose interleukin 2 and lymphokine-activated killer cells

Adoptive immunotherapy of human cancer was investigated in our institution as part of a National Cancer Institute extramural group study. This treatment, for patients with metastatic malignant melanoma, hypernephroma, and colon carcinoma, consisted of three phases: (a) 5 days of i.v. high-dose (10(5) units/kg every 8 h) interleukin 2, (b) 6 1/2 days of rest plus leukapheresis; and (c) 4 days of high-dose interleukin 2 plus three infusions of autologous lymphokine-activated killer cells. Toxicities included fever, chills, tachycardia, hypotension, vomiting, diarrhea, and fluid retention. Ascorbic acid is known to be important to cell-mediated immunity, and it has been reported to be depleted during physiologically stressful events. Therefore, we determined plasma ascorbic acid levels in patients (n = 11) before adoptive immunotherapy and before and after Phases 1, 2, and 3 of treatment. Patients entering the trial were not malnourished. Mean plasma ascorbic acid levels were normal (0.64 +/- 0.25 mg/dl) before therapy. Mean levels dropped by 80% after the first phase of treatment with high-dose interleukin 2 alone (0.13 +/- 0.08 mg/dl). Mean plasma ascorbic acid levels remained severely depleted (0.08 to 0.13 mg/dl) throughout the remainder of the treatment, becoming undetectable (less than 0.05 mg/dl) in eight of 11 patients during this time. Values obtained from 24-h urine collections on two of two patients indicated that ascorbate was not excreted in the urine. Plasma ascorbic acid normalized in three of three patients tested 1 mo after the completion of treatment. Unlike the results for ascorbic acid, blood pantothenate and plasma vitamin E remained within normal limits in all 11 patients throughout the phases of therapy. Responders (n = 3) differed from nonresponders (n = 8) in that plasma ascorbate levels in the former recovered to at least 0.1 mg/dl (frank clinical scurvy) during Phases 2 and 3, whereas levels in the latter fell below this level.     

Immunotherapy of murine hepatic metastases with lymphokine-activated killer cells expanded in serum-free media and recombinant interleukin 2

It has been shown that the systemic administration of lymphokine-activated killer (LAK) cells with recombinant interleukin 2 (RIL-2) is effective in reducing the number of established pulmonary and hepatic metastases in murine models. Similarly, this modality of therapy has been proven effective against certain selected human tumors as well. In view of the rising concern with transmission of virally related communicable diseases such as hepatitis and AIDS, we have undertaken the evaluation of a serum-free medium (AIM V) for the generation and expansion of murine LAK cells for use in in vivo tumor immunotherapy against murine hepatic metastases. Day 3 LAK cells generated in AIM V medium demonstrated a greater percentage of viable cells than cells generated in serum containing complete medium (CM) (mean percentage of yield, 59 versus 25%, AIM V medium versus CM, respectively, P less than 0.001, N = 6 consecutive experiments). When day 3 LAK cells were transferred to new medium (CM to CM and AIM V to AIM V), a highly reproducible expansion of these cells was demonstrated which was significantly better for cells expanded in AIM V medium versus cells expanded in CM (mean fold expansion on day 21 of culture; 201 versus 54, AIM V medium versus CM, respectively, P less than 0.005, N = 4 consecutive experiments). When day 3 LAK cells, day 5 expanded LAK cells, and day 13 expanded LAK cells grown in CM or in AIM V medium were given in vivo with RIL-2 to mice harboring hepatic metastases, cells grown in AIM V medium demonstrated an increased antitumor activity compared to cells grown in CM. As an example in experiment 1, the mean number of metastases with day 5 expanded LAK cells grown in CM and given with RIL-2 was 47 while the mean number of metastases with day 5 expanded LAK cells grown in AIM V medium and given with RIL-2 was 5 (P less than 0.002). These experiments demonstrate that AIM V medium can be utilized to generate greater numbers of murine LAK cells with enhanced in vivo antitumor activity compared to cells generated in CM. These findings could be applied to the expansion of cytotoxic cells for human antitumor therapy.     

Local administration of autologous lymphokine-activated killer cells and recombinant interleukin 2 to patients with malignant brain tumors

Lymphokine-activated killer cells (LAK cells) were induced from lymphocytes from patients with malignant glioma by using interleukin 2 (IL-2), and their killing activity was examined. Their LAK activity against Daudi cells was 66.2 +/- 13.1% and 48.7 +/- 12.7% against self glioma cells, 54.4 +/- 10.1% against K562 cells, 43.1 +/- 7.9% against Raji cells, and 33.5 +/- 16.2% against allogeneic glioma cells. The phenotype of these LAK cells was Leu 1 (++), 2a (+/-), 3a (++), 7 (+), and 11 (++). The phenotype of precursor LAK cells, on the other hand, was Leu 1 (-), 2a (-), 3a (+), 7 (-), and 11 (++). Other activated killer cells, including LAK cells, phytohemagglutinin-activated killer cells, autoactivated killer cells, and their precursor LAK cells, were studied serologically in order to identify their phenotypic characteristics. From these data, the LAK cell populations were considered to be polyclonal. Using these LAK cells plus IL-2, local adoptive immunotherapy was undertaken in 23 patients with recurrent malignant glioma. We injected, that is, autologous LAK cells plus IL-2 directly into the cavities of the brain tumors; 1.2 to 324 x 10(8) LAK cells per ml and 0.8 to 5.4 x 10(3) units of IL-2 were directly injected into the brain tumor by using an Ommaya reservoir. Definite tumor regression, improvement of some clinical symptoms, and continuous remission over 6 mo or more were observed in six, nine, and three patients, respectively. There were no marked side effects, except for slight fever and chill, in eight and three patients, respectively. These results suggested the possibility of induction of a sufficient number of LAK cells from the lymphocytes of the patients with recurrent malignant glioma, indicating that local adoptive immunotherapy by direct injections of LAK cells and IL-2 into the brain tumor will prove to be an effective means of immunotherapy. Additional follow-up of the patients will be required before its therapeutic value can be established.     

A new form of specific targeting cancer immunotherapy using anti-tumor monoclonal antibody-conjugated lymphokine-activated killer cells

Cross-linking of effector T cells to target cancer cells augments their tumor lytic activities. Here we describe a new method of conjugating lymphokine-activated killer (LAK) cells with cancer-specific monoclonal antibody. The LAK cells were biotinylated, treated with avidin, and conjugated with biotinylated monoclonal antibody. These monoclonal antibody-conjugated LAK cells showed specifically enhanced killing activities against anti-tumor antibody-reactive cancer cells, and cold target cells specifically inhibited their activities.     

Adoptive immunotherapy with interleukin 2 in oncology

Forty-seven patients with renal carcinoma were included in first line or rescue protocols of immunotherapy including IL2 alone or in association with LAK cells, INF alpha or TNF. The toxicity was mild and the mortality was 2% (1 patient). The response rate was 26%. Nineteen children with neuroblastoma received IL2 either alone or in combination with LAK cells. The morbidity and mortality were higher in patients with end stage disease who had previously received high dose and prolonged chemotherapy. In contrast, the toxicity was mild and transient in patients treated in the months following autologous bone marrow transplantation. The only complete response observed was in 1 child treated with IL2, 4 months after high dose chemotherapy and ABMT. Immunological analysis showed that the immunomodulatory effect of IL2 is very different depending on whether IL2 is used alone or in combination with other cytokines; moreover, the biological effect of IL2 is dependent on the immunological status of the patients prior to IL2 therapy.     

A new approach to generating antitumor effectors for adoptive immunotherapy using human adherent lymphokine-activated killer cells

Lymphocytes from human peripheral blood incubated with interleukin-2 (IL2) develop lymphokine-activated killer (LAK) activity with the ability to kill a wide variety of tumor cells in a non-major histocompatibility complex-restricted manner. Adoptive immunotherapy with LAK cells and IL2 has been reported to lead to a regression of solid tumors in some patients with advanced malignancies. Aiming to improve the effectiveness of clinical adoptive immunotherapy, we developed a procedure for selective enrichment from human blood mononuclear cells (MNC) of IL2-activated antitumor effector cells. These cells, termed adherent LAK (A-LAK) cells because of their characteristic property of adherence to plastic, demonstrated both higher proliferative potential and greater antitumor cytotoxicity than unseparated MNC. Human A-LAK cells represented only 1 to 4% of IL2-activated MNC at 24 h but expanded from 130- to 1100-fold in 20 days. They comprised a population highly enriched in CD3-Leu19+ effector cells with antitumor activity against fresh human solid tumor cells and established cell lines. A-LAK cells retained antitumor activity for up to 14 days when cultured in the presence of IL2. They also mediated antibody-dependent cytotoxicity. Large-scale generation of A-LAK cells from the blood of patients with cancer proved feasible and should yield populations that are effective in vivo at lower doses than those required with unseparated LAK cells. This offers the potential for improving the antitumor effects, reducing the toxicity, and facilitating the administration of adoptive immunotherapy in humans. A Phase I/II clinical trial utilizing A-LAK cells and IL2 in patients with melanoma and renal cell carcinoma is now in progress.     

Identification of a novel CD56- lymphokine-activated killer cell precursor in cancer patients receiving recombinant interleukin 2.

Circulating lymphokine-activated killer (LAK) cell activity in cancer patients receiving recombinant interleukin 2 (rIL-2) therapy is confined to cells expressing the CD56- surface marker. However, CD56- cells from these patients but not normal individuals have been reported to exhibit LAK cytotoxicity only following in vitro activation with rIL-2. Studies were performed to document the existence of CD56- LAK precursor cells and to phenotypically characterize this population in patients receiving rIL-2 therapy using fluorescence-activated cell sorter-purified CD56- cell subsets. Initial studies confirmed that CD56- cells exhibit NK activity [20 +/- 7 (SE) LU/10(6) cells] but not LAK activity (0 +/- 0 LU/10(6) cells) when evaluated directly from peripheral blood of patients receiving rIL-2. CD56- cells from patients but not normal individuals developed significant LAK cytolytic activity against NK-resistant COLO 205 targets (16 +/- 3 LU/10(6) cells) when cultured for 3 days with 1500 units/ml rIL-2. The CD56- LAK precursor activity was confined to cells expressing a CD56-CD16+ phenotype and a large granular lymphocyte morphology; little or no NK or LAK precursor activity was detectable in CD56-CD5+ T-cells from patients. Phenotypic characterization of CD16+CD56- cells revealed that this population is uniformly CD11a+,CD18+, and CD38+ and is heterogeneous in its expression of CD11b, CD11c, and CD16/Leu 11c. These results indicate that rIL-2 administration induces enhanced LAK precursor activity in a novel population of CD5-CD16+CD56- cells.     

Synergistic effect of Nocardia rubra cell wall skeleton and recombinant interleukin 2 for in vivo induction of lymphokine-activated killer cells

C57BL/6 mice inoculated i.p. with 3LL tumor cells were treated by local combination therapy with Nocardia rubra cell wall skeleton (N-CWS) and recombinant interleukin 2 (rIL-2). The combination treatment significantly prolonged their survival and augmented lymphokine-activated killer (LAK) activity of peritoneal cavity lymphocytes (PCL), compared with treatments with rIL-2 alone or N-CWS alone. After in vitro culture of peritoneal exudate mononuclear cells with rIL-2, the nonadherent population derived from N-CWS-injected tumor-bearing mice showed a significantly higher LAK activity than did that population derived from saline solution-injected mice. When N-CWS-induced PCL were cocultured with either N-CWS-induced macrophages or control macrophages in the presence of rIL-2, their LAK activity was higher than that of control PCL. Therefore, it was suggested that N-CWS-induced PCL themselves have a more potent ability as precursors of LAK cells. Phenotypic analysis on PCL populations revealed that N-CWS-induced PCL contained increased proportions of CD3+CD4-CD8- cells and asialo GM-1+ cells compared with control PCL. These results suggest that N-CWS selectively accumulates potent LAK precursors, namely, CD3+CD4-CD8- T-cells and asialo GM-1+ natural killer cells, at the injection site and that LAK cells are efficiently induced by subsequent administration of rIL-2.