The therapeutic effect of OK-432-combined adoptive immunotherapy against liver metastases from gastric or colorectal cancers

Twenty-four patients with liver metastases from gastric or colorectal cancer were treated with OK-432-combined adoptive immunotherapy (AIT). Lymphocytes isolated from regional lymph nodes or peripheral blood were cultured with medium containing T cell growth factor and sonicated tumor extract antigen (SE-Ag) for 9–13 days. The cultured lymphocytes were transferred mainly through the hepatic artery after the administration of OK-432, a streptococcal preparation. Sixteen of the 24 patients received a low dose of anti-cancer agents between the OK-432 injection and cell transfer. When cultured without SE-Ag, regional lymph node lymphocytes (RLNL) showed significantly (P<0.05) higher cytotoxic activity against autologous tumor cells and, on the contrary, lower cytotoxic activity against K562 than peripheral blood lymphocytes (PBL). When cultured with SE-Ag, cytotoxicity of RLNL against autologous tumor cells was nearly equivalent to that of PBL. The blastogenesis of fresh PBL to SE-Ag was significantly (P<0.05) augmented after the OK-432-combined AIT. Two patients showed complete response and 4 patients showed partial response among 19 patients who had evaluable lesions. Five patients whose liver metastases were resected were treated with OK-432-combined AIT as an adjuvant therapy. To date they are alive without recurrence in the liver.Abbreviations AIT adoptive immunotherapy - RLNL regional lymph node lymphocytes - SE-Ag sonicated tumor extract antigen     

A regimen of surgical adjuvant immunotherapy for cancer with interleukin 2 and lymphokine-activated killer cells

We designed a unique regimen of adoptive immunotherapy with lymphokine-activated killer (LAK) cells and recombinant interleukin 2 (rIL-2) for application with surgical adjuvant therapy of cancer. The regimen features the prolonged (6 consecutive days) s.c. administration of low-dose rIL-2 and the transfer ofex vivo generated LAK cells from regional lymph node lymphocytes, obtained at the time of surgical operation. According to this regimen, 5 patients with primary lung cancer received immunotherapy about 2 weeks after surgery (pulmonary lobectomy). Clinical toxicities included fever(5/5), fatigue(5/5), slight(< 5%) weight gain(5/5), increase of pleural effusion at the lobectomy site(2/5), and edema formation(1/5). All toxicities reversed within 4 days after the completion of therapy. Rebound lymphocytosis after therapy ranged from 2.4 to 5.5-fold (mean, 4.3-fold) over the baseline. Peripheral blood lymphocytes obtained during this lymphocytosis exhibitedin vitro LAK activity in 4 of 5 patients. Thus, the regimen is considered to be well-tolerable and immunologically active in regard to the postoperative state of the patients.     

A comparison of the suppressor and cytotoxic activities of the blood mononuclear cells during the adoptive immunotherapy of cancer patients using lymphokine-activated killers with a low dose of recombinant interleukin-2]

The suppressor and cytotoxic activities of mononuclear blood cells (MNC) were studied in 70 cancer patients (melanoma, renal carcinoma) undergoing adoptive immunotherapy (AIT). In the course of AIT the patients' MNC were treated in vitro with the recombinant interleukin-2 (RIL-2) in order to generate the lymphokine-activated killer (LAK) cells. Then patients received i/v 2.5-13.6 10(9) autologous LAK cells and RIL-2 (75000 u). Each course included 2-3 repeated infusions; the patients received 1-5 courses according to their clinical conditions. The cytotoxic activity of MNC was assessed by a routine method; but for evaluation of the suppressor activity we used a new technique based on separation of MNS populations in the Percoll gradient. Twenty-four hours after the completion of each AIT course the suppressor activity of MNC decreased drastically up to the zero level in some patients. The decrease in the suppressor activity inversely correlated with the rise in the cytotoxic activity on Mel-I (LAK-sensitive) and K-562 (natural killer-sensitive) target cells. The level of cytotoxicity in some patients reached 51.2%.     

Clinical therapeutic effect of adoptive immunotherapy using IL-2-cultured autologous lymphocytes

Our method of adoptive immunotherapy (AIT) using autologous IL-2-cultured lymphocytes differs from so-called LAK therapy in several points. We (1) obtain cultured lymphocytes from effusion lymphocytes (EL) or regional lymph-node lymphocytes (RLNL), when possible, rather than peripheral blood lymphocytes (PBL), (2) use crude IL-2 to induce T cell proliferation and to maintain killer activity, (3) use sonicated autologous tumor extract as antigen (Ag) to stimulate proliferation of cytotoxic T cells, and (4) pretreat the patients with local administration of OK-432 before AIT to induce effector cells that act synergistically with transferred killer cells. Surface marker analysis showed that OKT3, IL-2 receptor, Leu 2+15- cells were elevated while Leu 11a and Leu 3+8+ cells were decreased. Culture of RLNL augmented the expression of Leu 3+8- marker. Both of PBL and RLNL responded to Ag, and their auto-tumor killing activities were augmented in about half of the patients while rarely decrease by the addition of Ag. Response rates of patients with pleural effusion due to breast cancer and those with liver metastasis of breast cancer were 94% and 60%, respectively. Moreover, the survival was prolonged in the treated patients with pleural effusion or gastric cancer patients with peritoneal dissemination.     

Adoptive immunotherapy of cancer using activated Autologous lymphocytes-current status and new strategies-

After the discovery of interleukin-2 (IL-2), lymphokine-activated killer (LAK) cells, tumor-infiltrating lymphocytes (TILs), and cytotoxic T lymphocytes (CTLs) sensitized with the mixed lymphocyte-tumor culture (MLTC) system have been conducted in adoptive immunotherapy (AIT) trials during past 15 years. Although the overall response rate of tumor shrinkage was marginal (9%), locoregional administration of TILs for malignant effusions was effective (77%) for a decrease or disappearance of the effusions even in terminally-ill patients, resulting in an improvement of QOL. Recent advances for molecular understanding of antigen presentation and recognition have promoted us to enhance the efficacy of AIT by using cultured dendritic cells (DCs) for generating antigen-specific CTLs in vitro. The peptide-pulsed DC-activated killer (PDAK) cells showed tumor recognition against antigen-expressing cells, and were efficiently propagated with the IL2 plus immobilized anti-CD3 antibody (IL-2/CD3) culture system. Clinical trials using PDAK cells against patients with lung metastases are now progressed, in which peptides suitable for generating CTLs were chosen in individual patients using the method designated as host-oriented peptide evaluation (HPOE) approach. Moreover, DCs were introduced with tumor-derived RNA, which was amplified with the T7 promoter system, and then were used for stimulating lymphocytes. The tumor RNA-introduced DC-activated killer (TRiDAK) cells showed tumor-specific interferon-gamma spots even in a patient in whom we failed to generate PDAK cells using DCs and peptides, suggesting that the clinical trial of AIT using TRiDAK cells is warranted for the treatment of patients with metastatic cancer. Thus, more understanding of antigen-presentation and -recognition mechanisms and immune regulation systems may promote clinical applications of AIT to establish a novel modality of cancer treatment.     

Evaluation of basic procedures for adoptive immunotherapy for gastric cancer

Peripheral blood lymphocytes (PBL) of gastric cancer patients in advanced stages showed lymphokine activated killer (LAK) activities comparable to those of healthy donors, suggesting potential applicability of LAK cells induced from PBL stimulated with recombinant interleukin-2 (rIL-2) in adoptive immunotherapy (AIT) for gastric cancer. In order to generate a large number of LAK cells from PBL, lymphocytes were cultured with both rIL-2 and phytohemagglutinin (PHA). In this culture, the numbers of cells increased to a greater extent than those in culture with rIL-2 alone but cytotoxic activity did not augment, thus suggesting that this procedure would not afford sufficient clinical effects. On the other hand, a large number of LAK cells with high anti-tumor activities were efficiently induced from spleen cells of the patients by culture of rIL-2; hence clinical usefulness of these LAK cells is anticipated. In regional lymph node lymphocytes (RLNL) cultured with rIL-2, the cytotoxic activities were lower than in those induced in PBL, and a characteristic increase of CD8 + CD11 + suppressor T cells was observed after incubation with rIL-2. Nevertheless, an increase of CD4 + 4B4⁺ helper inducer T cells was also observed in RLNL after the culture with rIL-2. Furthermore, high cytotoxic activities were induced in RLNL in some cases in which metastasis to the regional lymph nodes was not detected. When gastric cancer patients were pretreated with biological response modifiers (BRM), especially with Lentinan, LAK cells from PBL showed higher NK and LAK activities as compared with those of patients without BRM pretreatment.This work was partly supported by a grant from Hokkoku Cancer Research Foundation.     

Use of human leukocyte antigen-mismatched allogeneic lymphokine-activated killer cells and interleukin-2 in the adoptive immunotherapy of patients with malignancies.

Clinical effects and side effects were investigated in the adoptive immunotherapy of patients bearing malignant diseases using human leukocyte antigen (HLA)-mismatched allogeneic lymphokine-activated killer (LAK) cells. Allogeneic LAK cells were induced from peripheral blood lymphocytes (PBL) of healthy donors with the same blood types as those of patients. Recently we succeeded in increasing the proliferation rate and enhancing the cytotoxic activity of LAK cells by means of initial stimulation with pokeweed mitogen (PWM, PWM-LAK cells). Five of 12 patients applied in the adoptive immunotherapy showed clinical effects such as partial or complete regression of pulmonary metastases and pleural effusion. All pulmonary metastatic lesions were eliminated in one case by this adoptive immunotherapy combined with chemotherapy. Toxic effects were chillness, fever and general fatigue which were reversible, and no allergic side effects occurred even though allogeneic LAK cells were injected frequently. In the patients who received more than 10(11) of allogeneic LAK cells, anti-HLA class I antibodies appeared without any evidence of autoantibody. However, immunological side effects were never experienced after injection of allogeneic LAK cells even when the anti-HLA class I antibodies existed in the patients; this phenomenon suggests the safety of the adoptive immunotherapy using allogeneic LAK cells. Taken together, allogeneic LAK cells could be considered as alternative therapy for patients with malignancies who could not supply sufficient materials of autologous LAK cells. Recently, LAK cells, particularly PWM-LAK cells were found to obtain significantly potent and prompt lectin-dependent cell-mediated cytotoxicity (LDCC). All tumor cells confluent in microtest plate well could be annihilated by PWM-LAK cells plus PWM less than 8 hours. New immunotherapy using PWM-LAK cells or lectin-stimulated LAK cells with PWM or other lectins is discussed.     

The anti-tumor efficacy of lymphokine-activated killer cells and recombinant interleukin 2 in vivo

We showed previously that adoptive immunotherapy with the combination of LAK cells and recombinant IL 2 (RIL 2) can markedly reduce pulmonary micrometastases from multiple sarcomas established 3 days after the i.v. injection of syngeneic tumor cells in C57BL/6 mice. In this report, we analyzed the factors required for successful therapy. Titration analysis in vivo revealed an inverse relationship between the number of pulmonary metastases remaining after treatment and both the number of LAK cells and the amount of RIL 2 administered. Fresh or unstimulated splenocytes had no anti-tumor effect; a 2- to 3-day incubation of splenocytes in RIL 2 was required. LAK cells generated from allogeneic DBA (H-2d) splenocytes were as effective in vivo as syngeneic, C57BL/6 (H-2b) LAK cells. The anti-metastatic capacity of LAK cells was significantly reduced or eliminated when irradiated with 3000 rad before adoptive transfer. The combined therapy of LAK cells plus RIL 2 was shown to be highly effective in mice immunosuppressed by 500 rad total body irradiation and in treating macrometastases established in the lung 10 days after the i.v. injection of sarcoma cells. Further, reduction of both micrometastases and macrometastases could also be achieved by RIL 2 alone when administered at higher levels than were required with LAK cells. The value of LAK cell transfer and of IL 2 administration for the treatment of tumors established at other sites is currently under investigation.     

Therapeutic efficacy of sequential therapy with OK-432, cyclophosphamide,IL2-cultured lymphocytes andin vivo IL2 against advanced murine plasmacytoma

BALB/c mice inoculated IP with a syngeneic plasmacytoma MOPC104E were treated with a combination of a streptococcal preparation, OK-432 (1 KE, 0.1 mg/mouse), low-dose of cyclophosphamide (CPA, 1 mg/kg) and adoptive transfer of tumor-bearer-spleen cells (2 x 10(7) cells) cultured with IL2 and sonicated tumor extract (adoptive immunotherapy; AIT). The consecutive protocol of OK-432 (day 8, 9 post inoculation) - CPA (day 10) - AIT (day 11) was the most effective. Rate of complete remission was highest when recombinant (r-) IL2 was injected to the mice after AIT. Moreover, another bacterial preparation, Nocardia rubra cell wall skeleton and another low-dose chemotherapy, Mitomycin C could be used successfully instead of OK-432 or CPA. Transfer test of intraperitoneal cells (tumor cells plus host cells) of mice on day 11 post inoculation (on the day of AIT) revealed that OK-432 augmented the susceptibility of peritoneal cells to cultured lymphocytes in inhibition of transplantability, and that CPA after OK-432 augmented the anti-tumor effect of tumor-bearer-spleen cells which act synergistically with cultured lymphocytes. This therapy schedule seems to be the best model to augment the effect of AIT with minimal side effect.     

HIF1A predicts the efficacy of anti-PD-1 therapy in advanced clear cell renal cell carcinoma

Immunotherapy for cancer has become a revolutionary treatment, with the progress of immunological research on cancer. Cancer patients have also become more diversified in drug selection. Individualized medical care of patients is more important in the era of precision medicine. For advanced clear cell renal cell carcinoma (ccRCC) patients, immunotherapy and targeted therapy are the two most important treatments. The development of biomarkers for predicting the efficacy of immunotherapy or targeted therapy is indispensable for individualized medicine. There is no clear biomarker that can accurately predict the efficacy of immunotherapy for advanced ccRCC patients. Our study found that HIF1A could be used as a biomarker for predicting the anti-PD-1 therapy efficacy of patients with advanced ccRCC, and its prediction accuracy was even stronger than that of PD-1/PD-L1. HIF1A is expected to help patients with advanced ccRCC choose therapeutic drugs.     

Immunomodulatory effects of systemic low-dose recombinant interleukin-2 and lymphokine-activated killer cells in humans

Summary The adoptive immunotherapy of human cancer using lymphokine-activated killer (LAK) cells in combination with high-dose systemic recombinant interleukin-2 (rIL-2) has been associated with global changes in several hematological and immunological parameters while imposing profound toxicity on patients. We have evaluated an alternative LAK cell therapy utilizing low-dose systemic rIL-2 in 27 consecutive patients with metastatic cancer. We report that the administration of systemic low-dose rIL-2 is also characterized by significant changes in immunological and hematological parameters, which are qualitatively similar to those induced by high-dose rIL-2. Low-dose systemic rIL-2, given by i.v. bolus, is cleared to baseline levels within 240 min of administration. The induction of lymphocytosis and eosinophilia, which has characterized other protocols, is also a feature of this protocol. In addition, low-dose systemic rIL-2/LAK cell immunotherapy results in increased peripheral blood mononuclear cell (PBMC) expression of T-cell activation markers such as OKIa, OKT10 and IL-2 receptor. PBMC sampled approximately 100 h after the final infusion of LAK cells demonstrated a statistically significant increase in their ability to kill natural killer (NK)-sensitive and NK-resistent cell lines such as K562 and Daudi compared to baseline values (P <.05). These data suggest that rIL-2-based immunotherapy using low-dose rIL-2 is capable of inducing quantitative hematological and immunological changes while (in combination with LAK cells) retaining the ability to mediate tumor regressionin vivo. Dr. Eberlein was a recipient of an American Cancer Society Career Development Award. This work is supported in part by NIH Grant CA-40555 and the Clinical Research Center Grant 20-9299     

The effect of radiotherapy on NKT cells in patients with advanced head and neck cancer

Background

Cancer immunotherapy with NKT cells is a potential new treatment strategy for advanced head and neck cancer. NKT cell therapy is promising due to its unique anti-tumor activity and higher degree of safety compared to current therapies. Radiotherapy is indispensable as a standard treatment for advanced head and neck cancer. To elucidate the possibility of using NKT cells as an adjuvant immunotherapy with radiotherapy, we examined the effect of radiotherapy on NKT cells in patients with head and neck cancer.

Methods

The number, IFN-γ production and proliferation capacity of NKT cells were analyzed before and after 50 Gy radiation therapy in 12 patients with stage IV head and neck squamous cell carcinoma. The cytotoxic activity of NKT cells was examined in vitro.

Results

The number of NKT cells in the blood varied widely between patients. After radiation therapy, the population of CD3 T cells decreased significantly, while the NKT cell population remained stable. The number of NKT cells was the same after radiation therapy as before. IFN-γ production from NKT cells collected just after radiotherapy was impaired after stimulation with exogenous ligand, but the proliferative responses of these NKT cells was enhanced in comparison to those collected before radiation therapy. Furthermore, the proliferated NKT cells displayed a significant level of anti-tumor activity.

Conclusion

NKT cells are relatively resistant to radiation and might therefore be suitable for adjuvant immunotherapy to eradicate remnant cancer cells in patients who have undergone radiation therapy.     

Glycosidically bound sialic acid levels as a predictive marker of postoperative adjuvant therapy in gastric cancer

Summary A group of 293 gastric cancer patients were examined to see if the preoperative value of glycosidically bound sialic acid is a predictor of prognosis and effectiveness of postoperative adjuvant therapy. All patients had gastrectomies and were histologically confirmed to have primary adenocarcinoma of the stomach. Some patients then received either postoperative adjuvant chemotherapy or immunochemotherapy. Patients with sialic acid levels less than 74.5 mg/dl survived significantly longer than those with sialic acid levels of 74.5 mg/dl or of 85.3 mg/dl and over. No significant differences in survival were found among patients treated by gastrectomy alone, gastrectomy plus chemotherapy and gastrectomy plus immunochemotherapy. However, patients with abnormally elevated levels of sialic acid survived significantly longer when they were treated with immunochemotherapy after gastrectomy than those treated by gastrectomy alone or with chemotherapy after gastrectomy. By using Cox's multivariate regression model, pTNM stages, postoperative adjuvant therapy (chemotherapy and immunochemotherapy) and preoperative serum levels of sialic acid were examined as prognostic variables. Postoperative therapy was a significant prognostic variable in patients with abnormally elevated levels of sialic acid. The preoperative serum level of sialic acid is a promising predictive marker of the response to postoperative adjuvant immunochemotherapy.     

Colon adenocarcinoma cells inhibit anti-CD3-activated killer cell induction

Adoptive immunotherapy with lymphokine-activated killer (LAK) cells has shown some promise in the treatment of certain cancers that are unresponsive to conventional treatment approaches. However, colon adenocarcinomas tend to respond poorly to LAK therapy, possibly as a result of tumor-induced immunosupprression. Recently, in vivo administration of anti-CD3 antibody has been shown to induce mouse T lymphocytes to mediate major-histocompatibility-complex(MHC)-unrestricted tumoricidal activity which is distinet from natural-killer-cell-derived LAK activity. It has therfore been suggested that anti-CD3 therapy may find application in tumor immunotherapy in humans. However, the effectiveness of anti-CD3-activated killer cell induction within the environment found in the vicinity of colon adenocarcinoma cells has not been evaluated. The present report demonstrates that colon cancer cells of human (HT-29) and mouse (MCA-38) origin markedly inhibit the generation of activated killer cells in murine spleen cell cultures. DNA synthesis and interleukin-2 production by spleen cells following stimulation with anti-CD3 antibody are also profoundly depressed in the presence of MCA-38 and HT-29 adenocarcinoma cells. MCA-38- and HT-29-mediated inhibition of activated killer cell development is exerted through the production of a tumor-associated soluble factor that is distinct from transforming growth factor or prostaglandins. Local immunosupression associated with sites of tumor growth may therefore represent a major obstacle to successful anti-CD3 immunotherapy of certain colon adenocarcinomas.     

Immunotherapy for superficial bladder cancer

The treatment of superficial bladder cancer requires adjuvant therapies besides transurethral resection because of a high recurrence rate after this standard treatment alone. Current adjuvant therapies involve intravesical chemotherapy for patients at low and intermediate risk for recurrence and progression, and intravesical bacillus Calmette-Guérin for patients at intermediate and high risk. However, these adjuvant therapies fail in a significant number of patients, dictating the need for new and improved adjuvant treatment modalities for superficial bladder cancer. Immunotherapy aiming at the modulation of the immune system of the patient is a promising alternative adjuvant. This review discusses the current status of the clinical development of various immunotherapy approaches for superficial bladder cancer, including passive immunotherapy, immune stimulants, immunogene therapy and cancer vaccination.     

Unimpaired ability to generate adherent lymphokine-activated killer (A-LAK) cells in patients with primary or metastatic liver tumors

Summary Adherent lymphokine-activated killer cells (A-LAK cells) obtained from human peripheral blood mononuclear cells represent a population of potent antitumor effectors enriched in interleukin-2(IL-2)-activated natural killer cells. This study shows that A-LAK cells can be successfully generated from the blood of patients with liver cancer not treated with adjuvant chemotherapy or irradiation. Mononuclear cells were isolated from the blood of 33 patients with liver tumors (6 benign, 10 primary malignant, 17 metastatic) at the time of liver resection. A-LAK cells were separated by adherence to plastic following activation of peripheral blood mononuclear cells in 1000 U/ml recombinant IL-2. A-LAK cells (enriched up to 92% in CD3^–CD56⁺ cells) showed better subsequent expansion and two to six times higher antitumor cytotoxicity per cell than unseparated LAK cells cultured under the same conditions. The ability to generate A-LAK cells with superior in vitro cytotoxicity from the blood of most patients with liver cancer indicates that adoptive cellular immunotherapy may be a feasible and new way of treatment for primary and secondary hepatic neoplasms in man.     

Adjuvant Bestatin immunotherapy in patients with transitional cell carcinoma of the bladder

Summary The first clinical results of an ongoing, prospective trial to determine the value of adjuvant Bestatin immunotherapy in the management of bladder cancer are presented. Patients with nonmetastatic transitional cell carcinoma of the bladder, scheduled for fulldose local radiation therapy (64 Gy), were randomly allocated to adjuvant oral Bestatin treatment (30 mg daily for at least 1 year), starting at completion of irradiation, or no Bestatin. The longest follow-up period of the 151 evaluable patients is 6 years. The results have shown that the disease-free survival of the patients taking Bestatin is significantly improved compared to the controls (p=0.04). However, the overall survival of the patients was not affected by the Bestatin treatment. The beneficial effect of Bestatin seemed to be more marked among men than women. Furthermore, statistical analyses of the patient material according to T tumor categories suggested that compared to the controls, patients with less advanced disease (T1 and T2) benefitted more from Bestatin treatment than those with more advanced tumors (T3 and T4). The results of this ongoing trial thus show that patients with bladder cancer benefit from adjuvant Bestatin treatment in terms of disease-free survival.     

Immunohistochemical assessment of the tumour-associated epitopes CD44v6 and E48 in tumour-free lymph nodes from patients with squamous cell carcinoma in the head-neck region.

We examined immunohistochemically 370 tumour-free lymph nodes from 41 patients with a head and neck squamous cell carcinoma (HNSCC) to clarify whether the tumour-associated epitopes CD44v6 and E48 are suitable for adjuvant postoperative immunotherapy. All the positively immunostained cells found were single cells. CD44v6+ cells were found in 55% of the lymph nodes, with their numbers increasing in pN>0-patients (62%). Only pN>0-patients had abundant to massive CD44v6+ cells. A comparison with mononuclear cells in lymphatic tissue from control patients suggested a similarity with activated T-cells. In the 41 cancer patients there were significantly fewer lymph nodes with E48+ cells (11%), but the number of E48+ cells increased in pN> 1-patients (29%) with predominantly abundant E48+ cells. We conclude from the comparison with the epithelial marker EMA that the E48+ single cells are epithelial in origin. Only a specific E48 peptide sequence appears suitable for adjuvant immunotherapy in patients with head-neck tumours.     

Influence of T cells on the expression of lymphokine-activated killer cell activity and in vivo tissue distribution

Lymphokine-activated killer (LAK) cells are currently being evaluated in several cancer centers for the immunotherapy of patients with a variety of cancers. Understanding the in vivo distribution of LAK cells should help to optimize their antitumor efficacy. As a model system to examine this issue, nylon wool column-passed rat lymphocytes were cultured in the presence of rIL-2 for 1 and 2 days. The resulting cells were divided into two populations; one that adhered to the plastic flasks and the second which did not adhere. The adherent cells were found to be highly cytotoxic against NK-sensitive and NK-resistant targets, whereas the nonadherent cells were unable to kill NK-resistant targets unless T cells were removed from this population. These results indicate that T cells present in IL-2 activated bulk splenocytes may interfere with the activity of LAK cells. Adherent or nonadherent LAK cells were evaluated for their pattern of in vivo distribution after i.v. inoculation. These cells were found to display a restricted pattern of distribution, localizing mainly in the lungs at 2 h after i.v. injection but redistributing into the liver and the spleen by 24 h. LAK cells were rarely recovered from the lymphoid tissues, including the peripheral lymph nodes and the mesenteric lymph nodes. However, if T cells were not removed from the LAK cell population, some radioactivity was recovered from the peripheral and mesenteric lymph nodes. Fractionation of 2 day-activated, nonadherent population on discontinuous Percoll resulted in the enrichment of large granular lymphocyte (LGL)/LAK activity in low density fractions (42% and 45% Percoll), whereas high density fraction (70% Percoll) contained T cells which showed no cytolytic activity. Upon transfer into syngeneic rats, the 42% fraction showed typical LAK migration. In contrast, the 70% fraction showed typical T cell migration. What is more important, removal of the granulated cells resulted in a population which have no granules and resemble large agranular lymphocytes known to be pre-LGL/LAK cells. Large agranular lymphocytes showed a pattern of distribution different from both T and LGL/LAK cells.     

Induction of LAK cells by high density dialyzing culture device and its cytotoxicity

Lymphokine activated killer (LAK) cells are generated by culture of lymphocytes with interleukin 2 (IL-2) in short term culture (3 to 5 days) and are used for adoptive immunotherapy for advanced cancer patients. The culture condition hitherto reported are essentially based on the rotating culture system, in which the maximum cell density was at 2 X 10(6) cell/ml and the cell recovery was usually less than 100%. The inability to induce LAK cells efficiently in vitro made the culturing of cells for therapy rather difficult and costly work because the mean infusion dose of LAK cells of one patient requires more than 1 X 10(10)/ml. We have therefore attempted to culture lymphocytes in 10 times higher concentration comparing with conventional methods. By using a new dialyzing culture system under continuous regulation of the amount of infused IL-2, nutrition medium, and pO2 and pCO2, we could culture cells at 2 X 10(7)/ml for more than 21 days and the resulted LAK cells showed a 100 times increase of activity on a per cell basis. By limiting dilution procedure, these killer cells mostly express T cell markers such as CD3 and CD8 but dose not express CD16.