Lymphokine-activated Killer Activity Research Articles

Clinical relevance of circulating mucosal-associated invariant T cell levels and their anti-cancer activity in patients with mucosal-associated cancer

Mucosal-associated invariant T (MAIT) cells are an antimicrobial MR1-restricted T cell subset and play an important role in immune defense response to bacteria. However, little is known about the role of MAIT cells in cancer. The aims of this study were to examine the level and function of MAIT cells in cancer patients and to evaluate the clinical relevance of MAIT cell levels. Ninety-nine patients with cancer and 20 healthy controls were included in this study. Circulating MAIT cell levels were significantly reduced in patients with mucosal-associated cancers (MACs), such as gastric, colon and lung cancers, but their capacities for IFN-γ, IL-17, or TNF-α production were preserved. This MAIT cell deficiency was significantly correlated with N staging and carcinoembryonic antigen level. Percentages of MAIT cells were significantly higher in cancer tissue than in peripheral blood and immunofluorescent labeling showed MAIT cell infiltration into colon cancer tissues. Circulating MAIT cells exhibited high levels of CCR6 and CXCR6, and their corresponding chemokines, such as CCL20 and CXCL16, were strongly expressed in colon cancer tissues. Activated MAIT cells not only had lymphokine-activated killer activity, but they also had direct cytotoxicity on K562 cells via degranulation of granzyme B and perforin. This study primarily demonstrates that circulating MAIT cells are reduced in MAC patients due to migration to mucosal cancer tissues and they have the potential to kill cancer cells. In addition, this circulating MAIT cell deficiency is related to the degree of cancer progression in mucosal tissues.

Abstract 3231: Identification of CD245 as myosin 18A, a receptor for surfactant A: A novel pathway for activating human NK lymphocytes effector function

Abstract Natural Killer (NK) cells were identified over 40 years ago as a subset of lymphocytes able to spontaneously kill tumor cells in the absence of pre-stimulation. Present in most mammalian and avian species, NK cells play a critical role in the anti-tumor and anti-infectious immunity and in reproduction. NK cell cytotoxicity is tightly controlled by a balance between signals delivered through the engagement of activating and inhibitory receptors. Beside these receptors, costimulatory molecules co-exist at the surface of activated NK cells to potentiate NK cells functions. 4-1BB (CD137) is a costimulatory receptor expressed on T, B and NK cells whose expression is triggered by engagement of the Fc receptors on the NK cell surface, as during antibody-dependent cell cytotoxicity (ADCC). Consequently the engagement of CD137 increases cetuximab-, rituximab-, and trastuzumab-dependent NK cell cytotoxic function in different cancer models. We previously described CD245 as an unidentified structure on the surface of human peripheral blood lymphocytes that was recognized by the monoclonal antibodies DY12 and DY35. We also reported that CD245 on NK lymphocytes was associated with tyrosine phosphatase activities. We found that CD245 is the unconventional myosin 18A, which is a receptor for the surfactant protein A (SP-A). We characterized the molecular and functional properties of CD245 and identified a novel co-activation pathway that potentiates the NK cell cytotoxicity. Stimulation by specific antibodies or its physiological ligand SP-A is able to increase NK cell degranulation and lymphokine-activated killer activity towards tumor B cells and EBV-infected B cells, respectively. We also found that myosin 18A stimulation is able to induce CD137 expression at the NK cell surface and that the myosin 18A-induced NK cell cytotoxicity toward CD137L-expressing tumor cells is dependent on the CD137/CD137L interaction. Thus, CD245 could represent a novel and promising target in cancer immunotherapy. Citation Format: Jérôme Giustiniani, Adèle de Masson, Anne Marie-Cardine, Jean-David Bouaziz, Christian Garbar, Martine Bagot, Yacine Merrouche, Armand Bensussan. Identification of CD245 as myosin 18A, a receptor for surfactant A: A novel pathway for activating human NK lymphocytes effector function. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3231.

IL-7 enhancement of antigen-driven activation/expansion of HIV-1-specific cytotoxic T lymphocyte precursors (CTLp).

CD8+ cytotoxic T lymphocytes are an important component in the immunologic control of human viral diseases. IL-7, a stromal cell-derived cytokine, has been demonstrated to enhance both anti-tumour and anti-viral CTL as well as lymphokine-activated killer (LAK) activity. We studied the ability of IL-7 to support the activation and the growth of in vitro antigen-specific CTL precursors (CTLp) present in peripheral blood mononuclear cells (PBMC) from HIV-infected patients. Results from these studies demonstrate that inclusion of IL-7 in a vaccinia/HIV-1 vector-based stimulation strategy greatly augmented overall CTL reactivities, whereas addition of IL-7 to unstimulated cultures failed to induce any significant anti-viral cytolytic activity. In four of six patients, HIV-specific lytic activities were significantly higher in cultures stimulated with antigen plus IL-7 compared with in vitro stimulation (IVS) with antigen alone. Cytotoxic activity was principally mediated by CD8+ effector cells, and CD3+/CD8+ cell expansion was increased by 2.7-fold in the presence of IL-7. In PBMC from seronegative donors, IL-7 enhanced anti-vaccinia CTL activities with less effect on cell proliferation. Furthermore, anti-gag CTL frequencies determined by limiting dilution analysis were increased by 2- and 10-fold in two asymptomatic patients following IVS plus IL-7 compared with antigen stimulation alone. Cytofluorimetric analysis revealed that IL-7 preferentially expanded CD8 memory cells (CD45RO+) and CD8+ lymphocytes expressing activation molecules. IL-7 was also able to support the growth of CD4+ lymphocytes, while having no effect on natural killer (NK)/K lymphocytes. Taken together, these data suggest that IL-7 acts cooperatively with the antigen supporting in vitro maturation of CTLp into functional cytotoxic effectors. Thus IL-7 may be an important biologic entity to consider as part of future immune-based therapies in which ex vivo expansion of antigen-driven CTL is an important determinant.

Pulmonary manifestations in Behçet disease: impaired natural killer cells activity

Background: Behçet’s disease (BD) is a systemic vasculitis with unknown aetiology, where, besides genetic predisposition, an immune dysregulation involving T and B lymphocytes and hyperactive neutrophils contribute to disease pathogenesis. The aim of this study was to determine the cytotoxicity of natural killer (NK) cells in bronchoalveolar lavage (BAL) from BD patients with pulmonary manifestations. Methods: BAL was performed in 27 patients with BD and pulmonary manifestations, 14 patients with Rheumatoid Arthritis (RA) and 23 healthy controls (HC). Related orphan receptor C (RORC) and forkheadbox P3 (FOXP3) mRNA transcript were determined in BAL by reverse transcription–polymerase chain reaction (RT-PCR). NK cells, NK cell cytotoxicity, and lymphokine-activated killer (LAK) activity against K562 cells were measured by flow cytometry. Proportions of NK precursors and expression of genes for IL-2 receptor β (IL-2Rβ; CD122), perforin, and granzyme in NK cells were measured by flow cytometry or RT-PCR. Results: The analysis of transcription factors revealed an increase in the RORC/FOXP3 ratio (Th17/Treg cells) in BAL from BD patients. Percentages of NK were significantly lower in BD than in RA patients and healthy controls. Purified NK cells derived from BD patients were found to have lower cytotoxicity and LAK activity than those from controls. This defect of NK cells in BD patients was related to down-regulation of perforin and granzyme expression in NK cells. Conclusion: In BD patients, the increased RORC/FOXP3 ratio indicated an inflammatory state of the lung. NK cells were decreased together with an impairment of their activity due to a defective expression of granzyme and perforin. These abnormalities possibly contribute to immune system dysregulation found in BAL of BD patients with pulmonary manifestations.

Pulmonary manifestations in Behçet disease: impaired natural killer cells activity

BackgroundBehçet’s disease (BD) is a systemic vasculitis with unknown aetiology, where, besides genetic predisposition, an immune dysregulation involving T and B lymphocytes and hyperactive neutrophils contribute to disease pathogenesis. The aim of this study was to determine the cytotoxicity of natural killer (NK) cells in bronchoalveolar lavage (BAL) from BD patients with pulmonary manifestations.MethodsBAL was performed in 27 patients with BD and pulmonary manifestations, 14 patients with Rheumatoid Arthritis (RA) and 23 healthy controls (HC). Related orphan receptor C (RORC) and forkheadbox P3 (FOXP3) mRNA transcript were determined in BAL by reverse transcription–polymerase chain reaction (RT-PCR). NK cells, NK cell cytotoxicity, and lymphokine-activated killer (LAK) activity against K562 cells were measured by flow cytometry. Proportions of NK precursors and expression of genes for IL-2 receptor β (IL-2Rβ; CD122), perforin, and granzyme in NK cells were measured by flow cytometry or RT-PCR.ResultsThe analysis of transcription factors revealed an increase in the RORC/FOXP3 ratio (Th17/Treg cells) in BAL from BD patients. Percentages of NK were significantly lower in BD than in RA patients and healthy controls. Purified NK cells derived from BD patients were found to have lower cytotoxicity and LAK activity than those from controls. This defect of NK cells in BD patients was related to down-regulation of perforin and granzyme expression in NK cells.ConclusionIn BD patients, the increased RORC/FOXP3 ratio indicated an inflammatory state of the lung. NK cells were decreased together with an impairment of their activity due to a defective expression of granzyme and perforin. These abnormalities possibly contribute to immune system dysregulation found in BAL of BD patients with pulmonary manifestations.

Immunologic Studies in Humans.

Immunologic Studies in Humans.

Effect of ziram on natural killer, lymphokine-activated killer, and cytotoxic T lymphocyte activity

Ziram is a carbamate pesticide, which is widely used throughout the world as a fungicide in agriculture and as an accelerating agent in latex production. In the present study, we investigated the effect of ziram at 0.031-4 μM in vitro on human natural killer (NK) and lymphokine-activated killer (LAK) and murine cytotoxic T lymphocyte (CTL) activity and found that it significantly inhibited all three activities in a concentration-dependent manner. To explore the mechanism of ziram-induced inhibition of NK activity, NK-92MI cells, a human NK cell line, were used. We previously confirmed that NK-92MI cells express CD56, perforin, granzyme (Gr) A, GrB, Gr3/K, and granulysin and are highly cytotoxic to K562 cells in the chromium release assay. NK-92MI cells were treated with ziram at 0.125-4 μM for 4 or 16 h at 37°C in vitro. Then, intracellular levels of perforin, GrA, GrB, Gr3/K, and granulysin were determined by flow cytometry. It was found that ziram significantly reduced Gr3/K, granulysin, perforin, GrA, and GrB levels. The extent of the decrease differed among the proteins, and the order was as follows: Gr3/K > granulysin > perforin, GrA, and GrB. Taken together, these findings suggest the ziram-induced inhibition of NK, LAK, and CTL activities to be at least partially mediated by decreases in the intracellular levels of Gr3/K, granulysin, perforin, GrA, and GrB.

Granzyme B-mRNA expression by equine lymphokine activated killer (LAK) cells is associated with the induction of apoptosis in target cells

Lymphokine-activated killer (LAK) cells are a subset of cytotoxic cells capable of lysing freshly isolated tumor cells. While LAK activity is typically measured using the 51Cr-release assay, here we used a non-radioactive flow cytometric method to demonstrate equine LAK activity. Equine peripheral blood mononuclear cells (PBMC) were stimulated in vitro with recombinant human interleukin 2 (hIL-2) to generate LAK cells. An equine tumor cell line, EqT8888, labeled with carboxyfluorescein succinimidyl ester (CFSE) was used as target cells. Following incubation of the targets with different concentrations of LAK cells, Annexin V was added to identify the early apoptotic cells. With increasing effector to target cell ratios, EqT8888 apoptosis was increased. We also measured interferon-gamma, granzyme B and perforin mRNA expression in the LAK cell cultures as possible surrogate markers for cytotoxic cell activity and found granzyme B mRNA expression correlated best with LAK activity. Also, we found that the reduced LAK activity of young horses was associated with decreased granzyme B mRNA expression. Our results indicate that fluorescence-based detection of LAK cell activity provides a suitable non-radioactive alternative to 51Cr-release assays and mRNA expression of granzyme B can be used as surrogate marker for these cytotoxic cells.

Down regulation of human natural killer cell–mediated cytolysis induced by blood transfusion: role of transforming growth factor‐β1, soluble Fas ligand, and soluble Class I human leukocyte antigen

Human natural killer (NK) cells are thought to play a role in antiviral response and tumor immune surveillance. The molecular mechanisms of down regulation of NK-cell activity observed after red blood cell (RBC) transfusion is still undefined. Both effects of blood transfusion (ex vivo) and supernatants (SNs) derived from RBC units unstored (RBC-0) or stored for 5 or 30 days (RBC-5 or -30, respectively) in vitro were analyzed on NK cell-mediated cytolytic activity. We have found that NK cells isolated from transfused patients on Day 3 lysed the NK-sensitive target cells K562 to a lesser extent than before transfusion. This down regulation of NK-cell activation was evident also for NK-cell killing mediated through the engagement of NK cell-activating receptors as NKG2D, NKp30, NKp46, and CD16. Transfused patients reacquired NK cell-mediated cytolytic activity from Day 5 to Day 7 after transfusion. SN from RBC-30, but not from RBC-0 or RBC-5, strongly inhibited the generation of lymphokine-activated killer (LAK) cells and lysis of the NK-resistant target cell Jurkat in a dose-dependent manner. Transforming growth factor-β1 (TGF-β1) blocking antibodies partially restored the generation of LAK activity. In addition, the depletion of both soluble Class I human leukocyte antigens (sHLA-I) and soluble Fas ligand (sFasL) from SN of RBC-30 completely restored the generation of LAK activity. Altogether, these findings would support the idea that blood transfusion-mediated down regulation of NK-cell activity is mediated by sHLA-I, sFasL, and TGF-β1.

Safety, Pharmacokinetics, and Immunomodulatory Effects of Lenalidomide in Children and Adolescents With Relapsed/Refractory Solid Tumors or Myelodysplastic Syndrome: A Children's Oncology Group Phase I Consortium Report

To determine the maximum-tolerated or recommended phase II dose, dose-limiting toxicities (DLTs), pharmacokinetics (PK), and immunomodulatory effects of lenalidomide in children with recurrent or refractory solid tumors or myelodysplastic syndrome (MDS). Cohorts of children with solid tumors received lenalidomide once daily for 21 days, every 28 days at dose levels of 15 to 70 mg/m(2)/dose. Children with MDS received a fixed dose of 5 mg/m(2)/dose. Specimens for PK and immune modulation were obtained in the first cycle. Forty-nine patients (46 solid tumor, three MDS), median age 16 years (range, 1 to 21 years), were enrolled, and 42 were fully assessable for toxicity. One patient had a cerebrovascular ischemic event of uncertain relationship to lenalidomide. DLTs included hypercalcemia at 15 mg/m(2); hypophosphatemia/hypokalemia, neutropenia, and somnolence at 40 mg/m(2); and urticaria at 55 mg/m(2). At the highest dose level evaluated (70 mg/m(2)), zero of six patients had DLT. A maximum-tolerated dose was not reached. No objective responses were observed. PK studies (n = 29) showed that clearance is faster in children younger than 12 years of age. Immunomodulatory studies (n = 26) showed a significant increase in serum interleukin (IL) -2, IL-15, granulocyte-macrophage colony-stimulating factor, natural killer (NK) cells, NK cytotoxicity, and lymphokine activated killer (LAK) cytoxicity, and a significant decrease in CD4(+)/CD25(+) regulatory T cells. Lenalidomide is well-tolerated at doses up to 70 mg/m(2)/d for 21 days in children with solid tumors. Drug clearance in children younger than 12 years is faster than in adolescents and young adults. Lenalidomide significantly upregulates cellular immunity, including NK and LAK activity.

Impaired differentiation and cytotoxicity of natural killer cells in systemic lupus erythematosus

To determine the cytotoxicity of natural killer (NK) cells and the level of differentiation of hematopoietic stem cells (HSCs) into NK cells in systemic lupus erythematosus (SLE). Patients with SLE (n=108), rheumatoid arthritis (RA; n=90), Behçet's disease (n=39), or ankylosing spondylitis (n=41) and healthy control subjects (n=173) were enrolled in the study. NK cell levels, NK cell cytotoxicities, and lymphokine-activated killer (LAK) activities against K562 cells were measured by flow cytometry. Gene expression was assessed by reverse transcription-polymerase chain reaction. NK cells were differentiated from peripheral blood and bone marrow HSCs in vitro. Percentages and absolute numbers of NK cells, cytotoxicities, and LAK activities were significantly lower in the peripheral blood of SLE and RA patients than in that of healthy controls. In particular, this NK cell deficiency was more prominent in patients with lupus nephritis and those with thrombocytopenia. Notably, purified NK cells derived from SLE patients, but not RA patients, were found to have lower cytotoxicities and LAK activities than those from healthy controls. This defect of NK cells in SLE patients was found to be related to lower numbers of NK precursors and to the down-regulation of perforin and granzyme in NK cells. The proliferative capacity of HSCs, the percentages of NK cells differentiated from HSCs, and NK cell cytotoxicities were significantly lower in SLE patients. In SLE patients, circulating levels of NK cells were diminished and their cytotoxicities were impaired. Furthermore, the differentiation of HSCs into NK cells was found to be defective. These abnormalities possibly contribute to immune system dysregulation in SLE.

Impact of surgery and chemotherapy on cellular immunity in pancreatic carcinoma patients in view of an integration of standard cancer treatment with immunotherapy

As surgery and chemotherapy may act as adjuvants providing antitumor immunity benefits, we ran phenotypical and functional immunomonitoring in patients with resectable pancreatic adenocarcinoma and advanced metastatic disease receiving combined treatment (cisplatin, gemcitabine, 5-FU). Blood was taken before/one month after resection; before/during chemotherapy. Controls were age- and gender-matched. Circulating lymphocyte, myeloid and plasmacytoid dendritic cell (MDC and PDC) subsets were examined by flow cytometry; functional activity by mixed lymphocyte reaction (MLR) for DC allostimulation, through 4-h 51Cr-release assay for Natural Killer (NK) and lymphokine-activated-killer (LAK) cell cytotoxicity; ELISA for spontaneous/activated cytokine release by PBMC and T cells. Significant differences occurred in several parameters between pretreatment patient and control values: fewer CD8+ cells and increased apoptosis-prone CD3+/CD95+ lymphocytes, higher frequency of MDC, reduced allostimulatory activity by ex vivo-generated DC, depressed LAK activity, elevated IL-10 and IL-12p40 production; impaired IL-12p70 and IFN-gamma production by stimulated PBMC and T cells. Only IL-12p70 level was correlated with survival. One month after radical, but not palliative surgery, the percentage of T-lymphocytes coexpressing CD3/CD95 decreased significantly, the stimulatory capacity of DC increased, and LPS-induced IL-12p70 release by PBMC rose concomitantly with the anti-CD3 stimulated-IFN-gamma production by T cells. In patients with locally advanced or metastatic disease, one and/or two combined drug cycles increased percentage of CD4+ cells and LAK cell cytotoxicity and decreased PDC frequency and spontaneous/LPS-stimulated IL-10 by PBMC. Results suggest immunological changes induced by surgical resection/combined chemotherapy indicate specific precisely-timed windows of opportunity for introducing immunotherapy in pancreatic cancer, possibly improving survival in this highly lethal disease.

High-Dose Intensity Pulse Interleukin-2 with Famotidine Has Activity in Metastatic Melanoma

Daily short intravenous (i.v.) infusions (pulses) of interleukin-2 (IL-2) have been developed to decrease toxicity while maintaining anticancer activity of this agent against melanoma. Such IL-2 schedules have previously been shown to promote lymphokine-activated killer (LAK) cell activity. Famotidine may increase LAK activity by increasing IL-2 internalization by the IL-2 receptor on lymphocytes. We treated 16 patients with metastatic melanoma using pulse IL-2 18 (15 patients) or 9 million IU/M2 (1 patient) i.v. over 15-30 minutes preceded by famotidine 20 mg i.v. daily for 5 days on an oncology inpatient unit. Cycles were repeated every 3 weeks until disease progression. Patient characteristics were as follows: 11 males, median age, 66, median ECOG performance status, 1; common metastatic sites: lymph nodes, lungs, subcutaneous, liver, and bone. Median number of cycles received was 3. Overall, 93% of planned doses were delivered. Most common toxicities were hypomagnesemia, fever, rigors, hypophosphatemia, and nausea/emesis. Three (3) patients had partial responses (19% response rate; 95% confidence interval: 6%-44%). A fourth patient, after resection of residual disease, remains a surgical complete responder at > 12 months. Responses occurred in lung, liver, lymph nodes, bone, and subcutaneous sites. Median response duration was 7 months. Pulse IL-2 with famotidine has activity in melanoma.

In vivotreatment with interferon causes augmentation of IL-2 induced lymphokine-activated killer cells in the organs of mice

Interferon-alpha (IFN-alpha) has been shown to synergize with IL-2 in the regression of a variety of established murine tumours and studies are underway to explore this combination in patients with advanced cancers as well. To understand the mechanism of synergy we have studied lymphokine-activated killer (LAK) cell activity in various compartments of mice in response to IFN-alpha and IL-2 administration. The effects of IFN-gamma, TNF-alpha and IL-4 were also examined. C57BL/6 mice were injected intraperitoneally with HBSS, IL-2 alone, IFN-alpha alone or both, two times a day for 7 days. On days 4 and 8, LAK activity was tested in a 4-h chromium release in cells obtained from lungs, spleen, and liver using fresh MCA-102 tumour cells as targets. The cells from control mice failed to lyse the MCA-102 target. IL-2 caused the generation of LAK activity and an increase in total cell yield in all the organs after 3 days of injection. IFN-alpha failed to generate LAK activity but when administered along with IL-2, caused synergistic enhancement of LAK lysis of MCA-102 target cells. Cell yield in this group was lower as compared with the IL-2-treated group. LAK activity tested after 7 days of IL-2 therapy was significantly decreased compared with that observed after 3 days. However, activity remained at as high a level after 7 days of therapy as after 3 days of therapy in animals treated with IFN-alpha and IL-2. FACS analysis revealed that asialo GM-1+ (ASGM-1) and NK1.1+ cells were increased in number in IL-2 and IL-2 plus IFN-alpha-treated spleen; however, the number of these cells was similar in both groups. In the liver, ASGM-1+ cells were higher in the IL-2 plus IFN-alpha group than in the group treated with IL-2 alone. By in vitro depletion utilizing antibody and Rbc' experiments, it was clear that both ASGM-1+ and NK1.1+ cells from the spleen mediated most of the cytotoxicity of MCA-102 targets. Pre-treatment irradiation (5 Gy) of mice completely abrogated the capability of IL-2 or IL-2 plus IFN-alpha to generate LAK activity. IFN-gamma also had a stimulatory effect on IL-2 induction of LAK activity. Tumour necrosis factor-alpha (TNF-alpha) and IL-4 failed to generate LAK activity and, in combination with IL-2, no additional stimulatory effect was observed.(ABSTRACT TRUNCATED AT 400 WORDS)

Defective interleukin-2 induction of lymphokine-activatedkiller (LAK) activity in peripheral blood T lymphocytesof patients with monoclonal gammopathies

The recombinant interleukin-2 (rIL-2) generation of lymphokine-activated killer (LAK) cells was investigated in peripheral blood T lymphocytes (PBT) of 16 patients with monoclonal gammopathy of undetermined significance (MGUS) and 32 patients with multiple myeloma (MM). LAK activity was significantly decreased in MM, but not in MGUS patients, and was partially recovered in MM in the remission phase. This finding was unexpected, because CD8+ CD11b+ cells, which contain LAK precursors, are significantly increased in MM. LAK activity was investigated in purified CD8+ CD11b+ lymphocytes to discriminate between an intrinsic defect or a defective regulation by other T cell subsets. These cells were intrinsically unable to generate LAK activity fully following rIL-2 stimulation. MM showed the more pronounced LAK deficiency, while MGUS patients showed intermediate values. Phenotyping revealed significantly increased proportions of Leu7+ and HLA-DR+ cells in MM patients. These data reveal another dysregulation of T cell effector functions in patients with monoclonal gammopathies and offer further evidence of the impairment of their cell-mediated immunity.

Changes in natural immunity during the course of HIV-1 infection.

The role of natural killer (NK) and lymphokine-activated killer (LAK) cell-mediated cytotoxicity in AIDS has yet to be established. The objective of this study was to determine inducible LAK cell responses at different stages of HIV-1 infection, and specifically to establish the participation of CD8 lymphocytes in these responses. Peripheral blood lymphocytes (PBL) were isolated from healthy seronegative (CDC-0) subjects and HIV-1+ individuals who were clinically asymptomatic (Centre for Disease Control group 2, CDC-2) or symptomatic (CDC-4) with regard to secondary opportunistic infection (OI). LAK cells were generated upon incubation of PBL with IL-2 and their cytolysis of K562 and U-937 targets was determined using chromium release assays. The role of CD8+ lymphocytes as progenitors and effectors of these LAK cell responses was determined by immunomagnetic depletion of CD8+ cells from precursor PBL and LAK cells, respectively. LAK cell-mediated cytotoxicities in HIV-1-infected individuals were reduced compared with seronegative controls without any corresponding changes in the relative proportions of CD56+ (NK) cells among groups. Depletions of CD8+ subsets from either PBL or LAK cells dramatically reduced total LAK cytotoxic responses and LAK activities per unit CD56+ cell in the OI-/CDC-2 seropositive population. No corresponding changes in LAK activities in seronegative control or HIV+/OI+/CDC-4 groups were observed. Levels of LAK activity against K562 targets in CDC-0/HIV- and CDC-4/HIV+ groups correlated with the percentage of CD56+ LAK cells; corresponding LAK activity in the CDC-2/HIV+ group correlated with the percentage of both CD56+ and CD8+ subsets. These findings suggest that adaptive changes in non-MHC restricted cytotoxic responses occur in HIV-1 individuals at early stages post-HIV infection, before the onset of opportunistic infection.

Combination chemo-immunotherapy: kinetics of in vivo and in vitro generation of natural killer cells and lymphokine-activated killer cells in the rat

Rats received a single high dose of cyclophosphamide (Cy) (150 mg/kg), followed 48 h later (on day 0) by immunization with a T cell-dependent soluble antigen, ovalbumin in Freund's complete adjuvant (FCA). The effect of this treatment on lymphoid cell subpopulations in the spleen, natural killer (NK) cell and interleukin-2 (IL-2) induced lymphokine-activated killer (LAK) cell activity was examined. Cy (with and without ovalbumin) caused a large relative increase (by day 14) in splenic OX8+, OX19- cells with NK morphology. A marked relative increase in fresh NK cell activity was noted after Cy + ovalbumin, but not consistently after Cy alone. Elevated NK activity was Cy dose- and time-dependent, was evident within 7 days post Cy/ovalbumin and persisted for at least 28 days. Pooled splenic mononuclear cells (MNC), obtained 14 days after Cy/ovalbumin, lost all cytolytic activity against YAC-1 cells when cultured in the absence of human recombinant IL-2 (rIL-2). In contrast, similarly maintained cells from normal rats displayed NK activity higher than normal 'fresh' levels. Upon culture in medium containing 500 U/ml rIL-2, however, 'augmented' NK activity was equivalent, on a per-cell basis, in both normal and Cy/ovalbumin-pretreated groups. LAK activity generated in vitro (i.e. against NK-resistant target cells) was significantly lower in the latter group, and the overall yield of cells was reduced. By day 21 after Cy/ovalbumin, augmented NK activity was significantly greater than controls, on a per-cell and total culture yield basis. Moreover, LAK activity was now similar between groups. It is concluded that the chemotherapy/immunization protocol which we have used can greatly enhance NK activity in vivo and that these cells are responsive to induction of LAK activity by IL-2 in vitro.

In vivoboosting of lung natural killer and lymphokine-activated killer cell activity by interleukin-2: comparison of systemic, intrapleural and inhalation routes

Natural killer (NK) cells are thought to play a role in host defence against malignancy and infection, in immunoregulation and as precursor cells in a generation of lymphokine-activated killer (LAK) cells which can lyse NK-resistant tumour cells. As the lung is a major site for malignancy and infection and as there are large numbers of lymphoid cells including NK cells in the interstitial compartment of the lung, we evaluated the capacity of interleukin-2 (IL-2), a lymphokine capable of augmenting NK activity in vitro, to augment lung NK cell activity in vivo, using different routes of IL-2 administration. We compared both systemic (i.v. and i.p.) and local (intrapleural and inhalation) routes of IL-2 administration (50,000 U/daily for 5 days) using CBA mice, assessing NK and LAK cell activity in the spleen (systemic) and in the lung. The target cells used for these studies were the YAC-1 (NK-sensitive) and P815, NO36 and HA56 (NK-resistant, LAK-sensitive) cell lines. Splenic NK activity was increased by 1.4-1.9-fold for i.v./i.p., respectively, compared with controls with both systemic routes of administration, and lung NK activity was increased 3.2-fold and 3.8-fold (i.v./i.p, respectively, P less than 0.05), to levels which were comparable to systemic (splenic) NK activity following the same therapy. Intrapleural IL-2 administration similarly enhanced lung NK activity (3.3-fold) and splenic NK activity (1.3-fold; P less than 0.05 versus controls for both). Surprisingly, inhaled IL-2 suppressed both splenic and lung NK cell activity (84 +/- 8% and 78 +/- 10% suppression, respectively, P less than 0.05). LAK cell activity was also enhanced in the lung by 1.8-8-fold in response to i.v., i.p. and intrapleural IL-2, whereas inhaled IL-2 was ineffective in generating LAK cell activity. These results suggest that the systemic and intrapleural administration of IL-2 effectively boost pulmonary NK and LAK activity whereas inhalation of IL-2 does not. Thus, in clinical situations where boosting of local lung NK or LAK cell activity is desired, these routes of IL-2 administration may be effective.

Effects of tumour necrosis factor-alpha (TNF-alpha), IL-1 beta and monocytes on lymphokine-activated killer (LAK) induction from natural killer (NK) cells and T lymphocytes.

Roles of monocytes and cytokines were investigated on LAK induction from T and NK cells. Monocytes augmented more T-LAK induction than did NK-LAK. Expression of IL-1 beta, TNF-alpha and interferon-gamma (IFN-gamma)-mRNA and their cytokine production were superior in NK cells compared with T cells in parallel with their LAK activities. An increase of TNF-alpha, IL-1 beta and IFN-gamma production was induced by co-culturing NK or T cells with autologous monocytes. The augmentation of T cell cytokine production and T-LAK activity by monocytes was more prominent than that of NK cells. TNF-alpha and IL-1 beta were generated 24 h after IL-2 stimulation, and these cytokines were able to almost substitute for monocytes in LAK induction. Conversely, LAK induction was almost completely suppressed by both anti-IL-1 beta and anti-TNF-alpha antibodies, if they were added within 24 h after the start of the LAK induction. IFN-gamma, which was produced at a later stage, scarcely affected LAK induction in spite of the cooperation with TNF-alpha. The results obtained indicate conclusively that the superiority of NK-LAK depends on their superior productivity of both IL-1 beta and TNF-alpha, and that the up-regulation of LAK induction by monocytes is largely due to the enhanced generation of both cytokines.

Long-term cultures of human peripheral blood lymphocytes with recombinant human interleukin-2 generate a population of virtually pure CD3+CD16-CD56- large granular lymphocyte LAK cells

It has been reported that lymphocytes from peripheral blood (PBL) cultured with interleukin-2 (IL-2) produce predominantly CD16+ lymphokine-activated killer (LAK) cells. We developed a two-step method to generate LAK cells from human PBL in long-term cultures (10-12 days) with recombinant human IL-2 (rhIL-2) and characterized the evolving LAK cell population by testing its phenotype and cytotoxic activity as a function of time. The starting PBL displayed some natural killer (NK) cytotoxicity but no LAK activity. At day 6, the cells were a mixed population of about 80% CD3+ and 6% CD16+ cells. Little proliferation was evident but strong LAK activity was detected. After 10-12 days, major cell expansion had occurred and they were essentially a pure (greater than 90%) CD3+ CD16- CD56- cell population large granular lymphocyte (LGL) by morphology that displayed strong non-MHC-restricted killing activity (greater than 200 lytic units). Over the same period of time, the CD16+ cells had almost completely regressed in these cultures. This preferential induction of CD+ LAK cells was not an effect of IL-2 concentration as 10 U/ml was as effective as 500 U/ml. Further characterization revealed a major population of CD4+ (60%) and CD8+ (30%) with a smaller fraction (less than 9%) of gamma delta + cells. These results indicate that a virtually pure CD3+ LAK cells population was produced with long-term cultures of lymphocytes from peripheral blood in rhIL-2, in which active proliferation of the CD3+ but not CD16+ cells occurred.