Deficient helper cell function as a cause of diminished pokeweed mitogen blastogenic responses in patients with non-Hodgkin's lymphomas

An investigation has been made of immunoregulatory T-cell function in the non-Hodgkin's lymphomas by comparing immunoregulation of healthy control and patient peripheral blood lymphocyte blastogenic responses to pokeweed mitogen. Normal mononuclear leukocytes (MNL) had significantly higher responses than patient MNL. MNL were subsequently separated into T- and non-T-cell fractions by differential E-rosette sedimentation for co-culture experiments. When normal non-T-cells and autologous irradiated T-cells were recombined, the mitogenic response again exceeded the response of patient non-T-cells recombined with their own irradiated T-cells. However, when normal non-T-cells were co-cultured with patient irradiated T-cells, the mitogenic response was diminished. Moreover, when patient non-T-cells were co-cultured with normal irradiated T-cells, a normal proliferative response occurred. These differences in non-T-cell response are not simply a result of allogeneic effects, since normal non-T-cell responses were the same regardless of whether autologous or normal allogeneic irradiated T-cells were used as helpers. Furthermore, co-culture of normal non-T-cells simultaneously with autologous irradiated T-cells and patient irradiated T-cells revealed no diminution of blastogenic response compared with co-cultures of normal non-T-plus autologous irradiated T only, suggesting no net suppression by patient irradiated T-cells. Studies with monoclonal antibodies revealed that patient T-cells had normal to increased ratios of OK-T4+:OK-T8+ cells. These results suggest that peripheral blood T-cells from patients with non-Hodgkin's lymphomas, despite the presence of a normal to increased ratio of OK-T4+:OK-T8+ cells, are functionally deficient in their helper capacity for non-T-cell blastogenic response to pokeweed mitogen. Abnormal helper T-cell function may explain some of the immune deficits in patients with non-Hodgkin's lymphoma and may be important in the pathogenesis of these diseases.     

氩氦刀治疗恶性肿瘤细胞免疫功能变化的临床分析

目的探讨恶性肿瘤患者经氩氦刀治疗前后T细胞亚群的变化。方法选取2005年6月-2006年12月的患者,均经病理诊断为Ⅲ期或Ⅳ期的晚期恶性肿瘤,105例患者瘤灶共计109个。病例选择标准：患者预期生存期大于3个月,实验期间均未接受氩氦刀以外的其他治疗。氩氦刀治疗前1周及治疗后1-2周收集标本,做T细胞亚群分析,外周血T细胞亚群CD3^＋、CD4^＋、CD8^＋、CD4^＋／CD8^＋采用流式细胞术检测。结果术后3-12个月复查CT示肿瘤明显缩小,部分患者肿瘤消失。恶性肿瘤患者在氩氦刀治疗后外周血CD3^＋、CD4^＋、CD4^＋／CD8^＋比治疗前明显升高（P〈0．05）。结论恶性肿瘤患者经氩氦刀治疗后可以增强细胞免疫功能,提高抗肿瘤能力。     

Tumor-dependent down-regulation of the ζ-chain in T-cells is detectable in early breast cancer and correlates with immune cell function

Suppressive factors produced by tumors or tumor-associated cells represent a major obstacle to immune-mediated tumor eradication and immunotherapy. We studied tumor-dependent changes in expression of the ζ-chain, a key molecule for the transduction of stimulatory signals through the T-cell receptor and activating receptors on natural killer (NK) cells, in patients with early (stages 1 and 2) breast cancer. Ex-vivo levels of ζ-chain expression, proliferation and cytokine expression in lymphocyte subpopulations were measured in breast tumors, their draining lymph nodes and in pre- and postoperative blood samples of cancer patients and healthy controls by multi-parametric flow cytometry. We found that T-cell ζ-chain expression in peripheral blood of breast cancer patients (n = 29) was down-regulated compared with healthy controls (n = 10) (p ≤ 0.033), which was most pronounced in stage 2 (n = 15, p ≤ 0.004). T- and NK-cell ζ-chain loss was most distinct in the tumor and decreased with increasing distance (p ≤ 0.015). After surgical tumor resection, peripheral blood ζ-chain levels normalized to those observed in healthy controls. ζ-chain expression in peripheral blood T-cells correlated with lymphocytic proliferative activity (p ≤ 0.035), and with the expression of proinflammatory cytokines in CD8+ T-cells (p ≤ 0.035). Breast cancer patients had lower numbers of circulating early memory CD8+ T-cells than healthy donors (p ≤ 0.000), correlating with lower T-cell ζ-chain levels (p ≤ 0.011). Our findings suggest that phenotypic and functional alterations in lymphocytes can be detected even in early stage breast cancer patients. The observed immunosuppression appears to be systemic and tumor dependent, as it is strongest in the tumor, correlates with tumor stage and normalizes after surgery.     

Intracellular cytokine profiles by peripheral blood CD3+ T-cells in patients with classical Hodgkin lymphoma

The intracellular profiles of T helper type 1 (Th1) and T helper type 2 (Th2) T-cell cytokines by peripheral blood (PB) CD3+ T-cells in patients with classical Hodgkin lymphoma (HL) has not been investigated before. The present study examines the cytoplasmic production of interleukin (IL) 2, 4, 10, tumour necrosis factor alpha (TNFalpha), and interferon gamma (IFNgamma) by activated PB CD3+ T-cells and compares them with the profiles observed with normal individuals. We report a significantly lower mean level of intracellular IL2, TNFalpha and IFNgamma at any time post-cell activation in cells isolated from patients with HL compared with the normal control group. In contrast, the mean level of cytoplasmic IL4 was significantly higher in the HL compared with the control group. No significant difference between the two groups was observed with IL10. In the HL patient group, there was a significantly higher percentage of CD3+CD8+ T-cells that synthesised IL4 compared with the CD3+CD4+ subpopulation, no such difference was observed in normal controls. The intensity of IL4 (expressed as relative median fluorescence) was significantly higher in the CD3+CD8+ cells of the patients with HL compared with the CD3+CD4+ sub-population, or with normal CD3+CD8+ cells. In conclusion, there is reduced intracellular IL2, TNFalpha and IFNgamma and increased cytoplasmic IL4 production by activated PB T-cells in patients with HL. The CD3+CD8+ sub-population is responsible for the increased levels of IL4.     

Lymphocyte response to pokeweed mitogen in chronic lymphocytic leukemia

The response of lymphocyte subpopulations to pokeweed mitogen (PWM) was studied in normal volunteers and patients with B-cell chronic lymphocytic leukemia (CLL). Since unfractionated peripheral blood mononuclear (PBM) cells from CLL patients consist of a markedly increased proportion of B-lymphocytes and a decreased proportion of T-lymphocytes, enriched fractions of CLL B-cells and CLL T-cells were cultured in 1:1 proportions in autologous and allogeneic combinations with normal B-cell and T-cell-enriched fractions. Cultures containing normal B-cells with either autologous or allogeneic normal T-cells responded well to PWM. CLL T-cells were capable of providing a helper function for both proliferation and differentiation of normal B-cells, which was not significantly different from that provided by allogeneic normal T-cells. CLL B-lymphocytes were unresponsive to PWM when cultured in the presence of either autologous CLL T-lymphocytes or allogeneic normal T-lymphocytes. The responsiveness of CLL B-cells was not restored by the addition of normal peripheral blood monocytes to the cultures. These experiments indicate that there is an intrinsic B-cell defect which prevents CLL B-lymphocytes from responding to PWM.     

Depletion of T-cells with the CD4+CD45R+ phenotype in lymphocytes that infiltrate subcutaneous metastases of human melanoma

We studied the phenotypes of lymphocytes extracted from 22 specimens of human melanoma, 11 s.c. metastases and 11 lymph node metastases, by two-color flow cytometry. Lymphocytes extracted from s.c. metastases were characterized by a significantly reduced ratio of CD4+ to CD8+ T-cells, as compared with peripheral blood lymphocytes from the same patients. Ten of 11 tumor-infiltrating lymphocytes from s.c. metastases, but only 1 of 11 peripheral blood lymphocytes, had a CD4/CD8 ratio of less than 1.0. This alteration was not observed for lymphocytes obtained from nodal metastases. Furthermore, almost all of the CD4+ T-cells in s.c. metastases expressed the antigen CD29w and were negative for the complementary antigen CD45R. In contrast, the CD29w/CD45R ratio of tumor-infiltrating lymphocytes from lymph node metastases was similar to that of matched peripheral blood lymphocytes. Thus tumor-infiltrating lymphocytes from s.c. metastases have the phenotype associated with true helper or antigen-committed T-cells, which could reflect their sensitization to tumor antigens, while tumor-infiltrating lymphocytes from lymph node metastases may represent merely an expanded residua of lymph node lymphocytes. Since tumor-infiltrating lymphocytes expanded in vitro are being tested as therapy for patients with advanced cancer, these observations may have important therapeutic implications.     

B-CLL cell surface markers and mitogen-induced thymidine uptake: a comparison between lymph node cells and peripheral blood lymphocytes in 25 patients

Lymphocytes from peripheral blood and lymph nodes from 25 patients with B-CLL were analysed by immunofluorescent staining of surface membrane immunoglobulin (SmIg), the B-cell marker B1, and the T-cell markers Leu 1/2/3/4. Tritium-thymidine uptake was measured in mitogen-stimulated 4-day cultures. Differences in these parameters between cells from the two sources in each patient were calculated with the paired T-test. All cell samples showed a clonal B-cell population. More blood lymphocytes than lymph node cells expressed the monoclonal SmIg (mu or gamma, p = 0.04; kappa or lambda, p less than 0.01), and T-cells were more frequent in lymph nodes (p = 0.01), where the T helper/suppressor ratio was higher. Furthermore, lymph node cells showed a higher thymidine uptake in response to the mitogens LPS, PWM, and Cowan (p = 0.01, p = 0.01, and p = 0.004, respectively), but there was no difference in the responses to EBV, DxS, TPA and PHA (p greater than 0.5). The higher response in lymph node cells to some mitogens might in part be explained by differences in the numbers of accessory cells, such as T-helper cells, but also by the existence of leukaemic B-cell subsets with different mitogen response patterns and different distributions within the lymphoid compartments. The characterization of subsets within a malignant cell clone might be of clinical importance.     

PD‐1 expression on peripheral blood T‐cell subsets correlates with prognosis in non‐small cell lung cancer

PD-1 expression in peripheral blood T-cells has been reported in several kinds of cancers, including lung cancer. However, the relationship between PD-1 expression in peripheral blood T-cells and prognosis after treatment with a cancer vaccine has not been reported. To elucidate this relationship, we analyzed PD-1 expression in the peripheral blood T-cells of patients with non-small cell lung cancer. The blood samples used in this study were obtained from patients enrolled in phase II clinical trials of a personalized peptide vaccine. Seventy-eight samples obtained before and after a single vaccination cycle (consisting of six or eight doses) were subjected to the analysis. PD-1 was expressed on lymphocytes in the majority of samples. The relative contents of PD1⁺CD4⁺ T-cells against total lymphocytes before and after the vaccination cycle correlated with overall survival (OS) with a high degree of statistical significance (P < 0.0001 and P = 0.0014). A decrease in PD-1⁺CD8⁺ T-cells after one cycle of vaccination also correlated with longer OS (P = 0.032). The IgG response to the non-vaccinated peptides suggested that the epitope spreading seemed to occur more frequently in high-PD-1⁺CD4⁺ T-cell groups. Enrichment of CD45RA⁻CCR7⁻ effector-memory phenotype cells in PD-1⁺ T-cells in PBMCs was also shown. These results suggest that PD-1 expression on the peripheral blood T-cell subsets can become a new prognostic marker in non-small cell lung cancer patients treated with personalized peptide vaccination.     

Immunologic abnormalities in angioimmunoblastic lymphadenopathy

In this study we describe the results of phenotypic, serologic, and functional analyses performed in nine patients with angioimmunoblastic lymphadenopathy (AILD). The study investigates the nature of the T-cell defects which seem to represent a consistent feature in this disease. The study, based on the analysis of T-cell subsets with monoclonal antibodies and on functional in vitro tests, showed the following main abnormalities: reduction of the absolute number of circulating T-cells; inversion of the CD4/CD8 ratio, both in the peripheral blood and in the involved lymph nodes; high percentages of activated T-cells (CD8+/HLA-DR+); defective T-cell response in vitro to the PHA mitogen; and minimal helper and enhanced in vitro suppressor functions. Some of these immunologic dysfunctions are also observed in acquired immune deficiency syndrome (AIDS) which has in common with AILD several clinical features. However, no evidence of HTLV-III infection could be demonstrated in our patients with AILD.     

Down-regulation of IL-18 receptor in cancer patients: its clinical significance

Interleukin-18 (IL-18) is a powerful inducer of interferon-gamma (IFN-gamma), a key immunoregulatory cytokine. Cellular immune responsiveness, as measured by IL-18-induced IFN-gamma production from peripheral blood mononuclear cells (PBMCs) in ELISA assay, was evaluated in 10 patients with advanced cancer and in 10 normal controls. Supernatant levels of IFN-gamma were detected at 2 hours after PBMCs culture and markedly increased thereafter in healthy volunteers. In contrast, IFN-gamma production in cancer patients was not detected during the culture period (0-72 hours). We also measured IL-18-stimulated IL-12 production in healthy volunteers and null response was observed in cancer-bearing patients. Next, we studied mRNA expressions of IL-18 receptor (IL-18R) and IFN-gamma in PBMCs in cancer patients and healthy volunteers by RT-PCR assay. Both mRNA levels of IL-18R and IFN-gamma were significantly decreased in cancer-bearing patients compared with normal controls. These results suggested that IL-18 responsiveness for IFN-gamma production in cancer-bearing patients was impaired. Using flow cytometric analysis, we studied T-cell subsets, CD3- CD56+ (NK cell), CD3+ CD45RO+ (memory T-cell), CD3+ CD95+ (Fas+ T-cell), CD3+ CD4+ (helper T-cell), CD3+ CD8+ (cytotoxic T-cell: CTL) and CD3+ V alpha24+ (NKT-cell), in cancer patients and normal controls. The NK and cytotoxic T-cells significantly decreased and NKT-cells had decreased tendency in cancer patients compared with normal controls. In contrast, memory T cells, Fas+ T-cells and helper T-cells were all significantly increased in cancer patients compared with normal controls. These results suggested that the underlying mechanism of impaired IL-18 responsiveness in PBMCs from cancer-bearing patients was, at least in part, ascribed to a drastic decrease of NK cells and CTL which constitutively and highly express IL-18R and also attributed to null production of IL-12 which up-regulates IL-18R.     

Peripheral blood and tumor-infiltrating mononuclear cell analysis in esophagus and head and neck cancer

We show a significantly decreased number of OKT3+ lymphocytes in the peripheral blood (PB) of cancer patients mainly due to a reduced number of OKT4 cells. OKT8 cells were also somewhat reduced. The numbers of DR+ and interleukin-2 receptor-bearing T-cells were significantly increased in patients. The tumor-infiltrating cells included OKT4+ AND OKT8+ lymphocytes. There was a significant correlation between the proportion of activated T-cells in PB and in tumor, as shown by DR and interleukin-2 receptor expression.     

Subpopulations of human T-lymphocytes. XIX. T-cells and T-cells with receptors for IgMFc (T mu), IgGFc (T gamma), or IgAFc (T alpha) in the peripheral blood and regional lymph nodes of patients with untreated breast cancer

Peripheral blood and regional lymph node mononuclear cells from 43 untreated patients with breast cancer were analyzed for the proportions of total T-cells and T-cells with receptors for the Fc portion of IgM (T mu), IgG (T gamma), or IgA (T alpha). Proportions of total T-cells and T mu cells both in peripheral blood and lymph nodes from breast cancer patients were comparable to those from health controls. The proportion of T gamma cells, however, was significantly (P less than 0.01) increased in the peripheral blood and lymph nodes from breast cancer patients as compared to that from controls. The proportion of T alpha in the peripheral blood was comparable; however, when compared to the number of T alpha cells in control lymph nodes, T alpha cells were increased (P less than 0.025) in the regional lymph nodes from patients with breast cancer. When data on the proportions of T-cells and T-cell subsets were analyzed according to the presence or absence of metastatic disease in the regional lymph nodes, the proportion of T gamma cells was significantly (P less than 0.025) higher in the peripheral blood from patients with metastatic disease than in patients with nonmetastatic disease. This study demonstrates an abnormality of T-cell subsets in the peripheral blood and the regional lymph nodes from patients with breast cancer. The significance of these observations is discussed.     

Induction of cytotoxic T lymphocytes by CEA peptide-pulsed γδ T-cells isolated from patients with advanced cancer

Cytotoxic γδ T-cells recognize antigens directly without the need for antigen processing and presentation. Recently, it was reported that they can also present antigens and proliferate in vitro. In this study, we examined whether γδ T-cells isolated from patients with advanced cancer can be used for immunotherapy. Twenty-two inoperable patients with multiple cancer metastases were enrolled in the study. There was no significant difference in the ratio of γδ T-cells within the peripheral blood mononuclear cell population isolated from healthy volunteers and cancer patients. γδ T-Cells isolated from cancer patients were expanded 2- to 5-fold using zoledronic acid or 2-methyl-3butenyl-1-pyrophosphate and IL-2. Autologous CD8(+) T-cells co-cultured with expanded CEA peptide-pulsed γδ T-cells from cancer patients with HLA-A24 killed more CEA-positive HLA-A24-matched gastric cancer cells and secreted higher levels of interferon-γ. These results suggest that γδ T-cells from cancer patients may be ideal candidates for adoptive immunotherapy.     

CD4+ T helper responses in squamous cell carcinoma of the head and neck

Anti-tumor immunity plays an important role in the development of and protection from malignancy. However, there is a lack of information regarding induction of CD4+ T helper responses in patients with squamous cell carcinoma (SCCHN). To explore anti-tumor immune responses against SCCHN, a permanent cell line, Gun-1 was established from a squamous cell carcinoma of the hypopharynx. In addition to its characterization, we performed mixed lymphocyte-tumor cell cultures (MLTC) using peripheral blood lymphocytes and autologous tumor cells. Furthermore, T cell responses to wild type (wt) p53-derived peptides were assessed. Gun-1 cells overexpressed p53 and were negative for HLA-A2 expression. No tumor-specific or wt p53-specific CD8+ CTL lines could be established from peripheral blood mononuclear cells (PBMCs) of this patient. Autologous tumor-specific HLA-DR-restricted CD4+ T helper clone was obtained by limiting dilutions using bulk populations from MLTC. This clone produced IFN-gamma but not IL-5 in response to autologous tumor cells. In addition, CD4+ T cells were generated from the patient's PBMCs which responded to two HLA-DP5-restricted wt p53-derived peptides. Our results suggest that the immune cells specific for autologous tumor as well as wt p53-derived epitopes are present in the peripheral circulation of this cancer patient. However, helper-type CD4+ T lymphocytes represent the predominant anti-tumor response.     

Immunoregulatory T-lymphocyte functions in patients with small cell lung cancer

The present study was performed to elucidate the differences in immune status between patients with small cell lung cancer (SCLC) and those with non-small cell lung cancer. The study group consisted of 18 patients with SCLC and 15 with non-SCLC. Two healthy volunteers and 13 patients with benign disease were also included in the present study as the non-cancer control. In the non-SCLC group, although not statistically significant, the percentages of both OKT3+ and OKT4+ T-lymphocytes in the peripheral blood lymphocytes (PBL) were slightly decreased, associated with a slight increase in the percentage of OKT8+ T-cells, and a slight decrease in the OKT4+ to OKT8+ T-cell ratio. In contrast, the PBL of the SCLC patients showed significantly lower proliferative responses to phytohemagglutinin and human recombinant interleukin 2 than did the PBL of both the SCLC patients and the noncancer control group. The ability of PBL to produce lymphokines (interleukin 2 and macrophage activating factor) was significantly impaired in the SCLC group but not in the non-SCLC group. These results suggest that suppression of helper T-cell functions and/or potentiation of suppressor T-cell functions should occur in patients with SCLC.     

Combined Blockade Of PD-1 and TIGIT is not Sufficient to Improve the Function Of CD8+ T-Cells in Chronic Lymphocytic Leukemia

Background and Objective: Blockade of immune checkpoint receptors in the treatment of cancers has been mentioned in several studies. Here, we investigated the efficacy of combined blockade of two inhibitory receptors, PD-1 and TIGIT, in restoring functional features of CD8+ T-cells in CLL. Methods: CD8+ T-cells were separated from the peripheral blood of 11 CLL patients and targeted with malignant B-cells isolated from the same patients. Cells were then stimulated with anti-CD3/CD28 and PMA/ionomycin to assess their proliferative response and cytotoxic activity using MTT and CD107a degranulation assays, respectively. Cytokine production of isolated CD8+ T-cells was also determined using ELISA. Results: There were no significant differences in proliferation and cytotoxic activity of CD8+ T-cells co-blocked with anti-PD-1/TIGIT compared to those single blocked with anti-PD-1, anti-TIGIT, or the control antibody. There was no significant difference in cytokine production of mentioned groups, either. Conclusions: Collectively, combined blockade of PD-1 and TIGIT failed to restore the proliferation and function of CD8+ T-cells isolated from CLL patients.     

Effect of low dose cyclophosphamide on the immune system of cancer patients: depletion of CD4+, 2H4+ suppressor-inducer T-cells

We studied peripheral blood lymphocytes (PBL) from 42 patients with metastatic melanoma undergoing treatment with cyclophosphamide (CY) plus melanoma vaccine to determine whether CY immunopotentiation could be related to depletion of T-cells that function as inducers of suppression. Every 28 days, the patients were given CY, 300 mg/m2 i.v., followed 3 days later by the intradermal injection of autologous, irradiated melanoma cells mixed with Bacillus Calmette-Guérin. PBL were separated by density gradient centrifugation and cryopreserved until needed for testing. They were stained with monoclonal antibodies directly conjugated to fluorescein isothiocyanate or phycoerythrin and analyzed by two-color flow cytometry. At no time after the initiation of CY plus vaccine were there any significant changes in the percentages of helper-inducer T-cells (CD4+), suppressor-cytotoxic T-cells (CD8+), or the subpopulation of CD8+ cells expressing Leu 15, a marker for suppressor cells. Treatment of melanoma patients with CY plus vaccine resulted in a progressive fall in the proportion of CD4+ T-cells expressing the 2H4 (CD45) antigen, which identifies inducers of suppression. The reduction of CD4+, 2H4+ T-cells did not become apparent until day 28 after the first dose of CY and reached statistical significance only on days 49 (21 days after the second dose) and 105 (21 days after the fourth dose) (mean changes +/- SE: day 49, -5.4 +/- 1.4%, P less than 0.01; day 105, -9.1 +/- 2.2%, P less than 0.01; t test for nonindependent samples). In contrast, the proportion of CD4+ T-cells expressing the antigen 4B4 (CDw29), which are true helper cells, increased slightly, although not significantly, following the institution of CY plus vaccine (mean changes: day 49, +2.9 +/- 2.1%; day 105, +3.6 +/- 2.4%). Similar results were obtained when absolute numbers of circulating cells, rather than percentages, were analyzed. Thus the number of CD4+, 2H4+ T-cells fell from a mean of 395,000/ml on day 0 to 309,000/ml on day 49 (P less than 0.01) to 256,000/ml on day 105 (P less than 0.05). The absolute number of CD4+, 4B4+ cells remained unchanged at the same time points. These changes were not due to progression of metastatic disease, since a comparison of patients with progressive metastases with those who were rendered disease free by surgery showed no significant differences in the reduction of the percentage of CD4+, 2H4+ T-cells.(ABSTRACT TRUNCATED AT 400 WORDS)     

Effect of anti-CD3 antibody on the generation of interleukin-2-activated lymphocytes from tumor tissues of gastrointestinal cancer.

BACKGROUND. The efficiency of anti-CD3 antibody (OKT3) for adoptive immunotherapy using lymphokine-activated killer (LAK) cells generated from tumor-infiltrating lymphocytes (TIL), regional lymph node lymphocytes (RLNL), and peripheral blood lymphocytes (PBL) was investigated. METHODS. TIL, RLNL, and PBL derived from 39 patients with gastrointestinal cancers (16 gastric cancers, 17 colorectal cancers, and 6 esophageal cancers) were cultured for 4 weeks with 200 U/ml of recombinant interleukin-2. To one group, solid-phase 10 micrograms/ml OKT3 was added during the initial culture period (day 2 or 4). Cytotoxicity against K562 cells (NK-like activity) and Daudi cells (LAK activity) and the phenotypes of effector cells generated after culturing for 2-3 weeks were studied. RESULTS. Proliferative responses were significantly increased by OKT3 in each type of effector cell (P less than 0.01); in particular, TIL expanded more by OKT3 than PBL and RLNL (P less than 0.01). The population of CD8+ CD11b- cytotoxic T-cells in OKT3-stimulated groups was significantly larger than that in unstimulated groups (P less than 0.01), whereas no differences were observed with CD4+ cells (helper/inducer T-cells) and CD8+ CD11b+ cells (suppressor T-cells). OKT3 enhanced the NK-like activity of TIL and PBL but did not affect their LAK activity. OKT3 suppressed the NK and LAK activity of RLNL. CONCLUSIONS. OKT3 stimulation did not significantly enhance the LAK activity, but the authors propose that OKT3 could be an effective addition to adoptive immunotherapy using TIL due to an increased proliferation and generation of a large cytotoxic T-cell population.