TNF-alpha and IFN-gamma reverse IL-4 inhibition of lymphokine-activated killer cell function

Circulating Tumor Cells (CTC) Are Associated with Defects in Adaptive Immunity in Patients with Inflammatory Breast Cancer

Background: Circulating tumor cells (CTCs) play a crucial role in tumor dissemination and are prognostic in primary and metastatic breast cancer. Peripheral blood (PB) immune cells contribute to an unfavorable microenvironment for CTC survival. This study aimed to correlate CTCs with the PB T-cell immunophenotypes and functions of patients with inflammatory breast cancer (IBC).

Methods: This study included 65 IBC patients treated at the MD Anderson Cancer Center. PB was obtained from patients prior to starting a new line of chemotherapy for CTCs enumeration by CellSearch^®, and T cell phenotype and function by flow cytometry; the results were correlated with CTCs and clinical outcome.

Results: At least 1 CTC (≥1) or ≥5 CTCs was detected in 61.5% or 32.3% of patients, respectively. CTC count did not correlate with total lymphocytes; however, patients with ≥1 CTC or ≥5 CTCs had lower percentages (%) of CD3+ and CD4+ T cells compared with patients with no CTCs or <5 CTCs, respectively. Patients with ≥1 CTC had a lower percentage of T-cell receptor (TCR)-activated CD8+ T cells synthesizing TNF-α and IFN-γ and a higher percentage of T-regulatory lymphocytes compared to patients without CTCs. In multivariate analysis, tumor grade and % CD3+ T-cells were associated with ≥1 CTC, whereas ≥5 CTC was associated with tumor grade, stage, % CD3+ and % CD4+ T cells, and % TCR-activated CD8 T-cells synthesizing IL-17.

Conclusions: IBC patients with CTCs in PB had abnormalities in adaptive immunity that could potentially impact tumor cell dissemination and initiation of the metastatic cascade.

Differential cytokine regulation of natural killer cell-mediated necrotic and apoptotic cytotoxicity

Natural killer (NK) cells can kill target cells by either necrotic or apoptotic mechanisms. Using the 51Cr-release assay to measure necrotic death of target cells, neonatal NK cells had low NK activity (K562 targets) and high lymphokine-activated killer (LAK) activity (Daudi targets) compared with adult cells, as has been previously reported. Using a 125I-deoxyuridine (125I-UdR) release assay, cord cells were shown to also have higher apoptotic LAK activity against YAC-1 target cells. Interleukin-4 (IL-4) inhibited interleukin-2 (IL-2)-induced necrotic killing of target cells by adult effectors but had no such inhibitory effect on cord cells. In contrast, IL-4 inhibited both adult and cord LAK cytotoxicity of YAC-1 target cells by apoptotic mechanisms with higher suppression observed in cord cell preparations. Using a colorimetric substrate conversion assay, IL-2 induced higher, and IL-4 had a more significant suppressive effect on, cord cell granzyme B enzyme activity compared with adult cells, paralleling apoptosis cytotoxicity data. Co-culture of either adult or cord LAK cells with IL-4 had a similar inhibitory effect on granzyme B protein expression, as detected by Western blotting. In contrast, IL-4 did not inhibit perforin expression, thereby defining IL-4 as a cytokine that can differentially regulate the NK cell-mediated cytotoxicity processes of apoptosis and necrosis. The differential sensitivity of cord cells to cytokine regulation of cytotoxicity may also have implications for cord blood transplantations, as NK cells are known to function as an effector cell in both graft-versus-host disease and in the graft-versus-leukaemia phenomena.

Regulation of interleukin-4 production and cytokine-induced growth potential in peripheral T-cell non-Hodgkin's lymphomas

The malignant cells in tumour tissues produce cytokines/growth factors that may influence tumour growth, tumour immunogenicity and host immune response. We demonstrate that lymph node cell (LNC) purified neoplastic T cells from CD4+ peripheral T-cell lymphoma (CD4+ PTCL) and CD8+ PTCL spontaneously, and after stimulation with anti-CD3, secreted high amounts of interleukin-4 (IL-4) as compared to LNC-purified CD4+ and CD8+ non-malignant T cells. Furthermore, IL-4 was observed to be the most potent cytokine that induced in vitro proliferation and growth of the malignant T cells. Moreover, malignant T-cell-derived IL-4 secretion was augmented by exogeneous recombinant human interferon-gamma (IFN-gamma) and was profoundly inhibited by IL-2. Because IL-4 was shown to be a locally active cytokine with a wide range of immunoregulatory properties, regulation of IL-4 production by IFN-gamma and IL-2 in malignant T cells may be one of the important parameters to be assessed in the design of anticancer-specific immunotherapy. In summary, we report that malignant T cells produce IL-4, a type 2 cytokine (Th2 cell response) that acts as a growth factor and which may play a critical role in PTCL disease mechanism.

Differential regulation of interleukin-12- and interleukin-15-induced natural killer cell activation by interleukin-4

The regulation of human natural killer (NK) cell activation is under the control of a network of regulatory signals provided by cytokines. In the present study, we investigated the functional interaction between interleukin (IL)-4 and two monocyte/macrophage-derived cytokines, IL-12 and IL-15, during the process of NK stimulation. Using freshly isolated human NK cells, we have demonstrated that IL-4 negatively regulates lymphokine-activated killer (LAK) activity induced by IL-15 against the NK-resistant Daudi target cells. In contrast, IL-4 had no effect on IL-12-stimulated LAK generation. The differential effect of IL-4 on NK cell activation by IL-12 and IL-15 correlates with its ability to increase or to down-regulate the level of tumor necrosis factor-alpha and interferon-gamma release by NK cells, respectively. In contrast, endogenous transforming growth factor-beta 1 does not appear to be involved in the IL-4 regulatory pathway. Furthermore, while IL-4 was found to decrease the basal expression of the IL-2 receptor beta subunit utilized by IL-15, it had no effect on the expression of the beta 1 chain of the IL-12 receptor compared to untreated cells. Northern blot analysis indicated that the IL-4 regulatory effect on NK lytic function was associated with its capacity to down-regulate granzyme B and perforin gene transcription in response to IL-15 and its failure to affect the expression of both gene's in response to IL-12. Together, these data suggest the existence of a distinct cross-talk between IL-4 and IL-15 or IL-12 signaling pathways during the regulation of human non-major histocompatibility complex-restricted cytotoxicity.

Differential secretion of TNF-alpha and IFN-gamma by human peripheral blood-derived NK subsets and association with functional maturation

Natural killer cells can be separated into three major subsets (free, binder, and killer) based on their ability to bind and kill sensitive target cells. The nonbinder, nonkiller free cells are the most immature and can be activated to become binders and killers. Natural killer (NK) cells synthesize and secrete several cytokines that are intimately involved in NK activation. This study investigated the secretion of tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) by purified NK cells and NK subsets following activation by various stimuli. K562 target cells stimulated secretion of both TNF-alpha and IFN-gamma by both the binder and the killer subsets but not by the free subset. IFN-alpha activated the secretion of IFN-gamma only, whereas IL-2 activated the secretion of both TNF-alpha and IFN-gamma by the binder and killer subsets and secretion was augmented by the addition of K562 to the cultures. Phorbol myristate acetate (PMA) and ionophore stimulated TNF-alpha and IFN-gamma secretion in both the binder and the killer subsets, though IFN-gamma secretion was more pronounced in the binder subset. Activation of TNF-alpha and IFN-gamma secretion was dependent on de novo protein synthesis. Analysis at the single-cell level demonstrated that the binder subset had the highest frequency of cells secreting IFN-gamma. These results demonstrate that both the binder and the killer subsets can be activated to secrete TNF-alpha and IFN-gamma, whereas the free NK subset secretes little or no TNF-alpha and IFN-gamma following activation. These data suggest that the ability of NK cells to secrete TNF-alpha and IFN-gamma following activation correlates with the functional stage of maturation of NK cells.

Longer local retention of adoptively transferred T-LAK cells correlates with lesser adhesion molecule expression than NK-LAK cells

The local retention of adoptively transferred lymphokine (IL-2)-activated killer (LAK) cells was examined in 11 patients with head and neck carcinoma. Unseparated lymphocytes, T and natural killer (NK) cells isolated from patients were cultured with IL-2 for 7 days, labelled with 99mTc-HMPAO, and immediately injected back into the respective donors via the superficial temporal artery or locally into the tumour tissue. The injected LAK cells were periodically traced using a gamma camera, and the LAK cell retention rate was calculated from the radioactivity. One hour after the injection, about 70% of the locally infiltrated LAK cells remained in the tumour tissue, while about half of the LAK cells transferred via the regional artery were dislodged from the tissue. LAK cells induced from T cells (T-LAK) were retained in the tissue for a longer time than LAK cells induced from NK cells (NK-LAK). T-LAK were less chemotactic and less adherent to human umbilical vein endothelial cells (EC), and showed lesser migration through EC. Flow cytometric analysis revealed higher expression of CD11a, CD11b, CD18 and CD49d on NK-LAK compared with T-LAK. MoAbs against these adhesion molecules suppressed adhesion and migration of LAK cells. These results indicate that the rapid disappearance of NK-LAK from the tissue is associated with their greater chemotactic and adhesive as well as migratory activities depending on differing expression of adhesion molecules.

All trans retinoic acid enhances human LAK activity

All trans retinoic acid has various effects on normal and malignant cells. Lymphokine-activated killer (LAK) activity can be derived from T lymphocytes and natural killer cells. This study shows that all trans retinoic acid significantly enhances this activity by increasing production of tumour necrosis factor and gamma interferon, which results in enhanced expression of the p55 part of the interleukin 2 receptor. This effect is dependent on the concentration of all trans retinoic acid and the length of time of culture.

Interleukin-6 is a mediator of TNF-alpha regulation of LAK cell function

TNF-alpha at 50-100 U/ml synergizes with IL-2 in enhancing LAK activity and IL-6 production in low-dose IL-2 (1-10 U/ml) culture of human PBL. High-dose TNF-alpha (> or = 200 U/ml) has less effect and even sometimes resulted in lowering of both LAK activity and IL-6 production below control levels. TNF-alpha-mediated regulation of low-dose IL-2 activation occurs even at late stages (effector phase) of LAK development. IL-6, as previously reported, acts at late stages of low-dose IL-2 culture to enhance LAK, but does not stimulate TNF-alpha production. The combined addition of TNF-alpha and IL-6 to late stages of IL-2 culture does not produce any additive or synergistic effect on LAK. We tested for the relative roles of TNF-alpha and IL-6 in late stage regulation of LAK development with antibodies (Abs) to these cytokines. Anti-IL-6 Ab abrogates late phase LAK enhancement by TNF-alpha, while anti-TNF-alpha Ab has no effect on IL-6 augmentation of LAK cytotoxicity. IL-2 added to PBL culture at doses greater than 10 U/ml induces production of both TNF-alpha and IL-6. Addition of anti-TNF-alpha Ab at late stages of high-dose IL-2 (> or = 20 U/ml) culture decreases both LAK cytotoxicity and IL-6 production, and the inhibition of LAK is reversed by the addition of IL-6. By contrast, anti-IL-6 Ab decreases LAK cytotoxicity, but does not alter TNF-alpha production, and the inhibition of LAK is not reversed by addition of TNF-alpha. These data indicate that TNF-alpha is important for both LAK development and IL-6 secretion in PBL, and that IL-6 is the proximate mediator in TNF-alpha regulation of these cytotoxic cell functions.

Interferon-gamma and interleukin-4 reciprocally regulate the production of monocytes/macrophages and neutrophils through a direct effect on committed monopotential bone marrow progenitor cells

We studied the direct effects of interferon-gamma (IFN-gamma) in single cell colony assays of CD34+HLA-DR++ bone marrow progenitor cells stimulated by either granulocyte-colony-stimulating factor (G-CSF), interleukin(IL)-3, granulocyte/macrophage-colony-stimulating factor (GM-CSF), combinations of these CSF or medium conditioned by the 5637 human bladder carcinoma cell line. In this culture system IFN-gamma stimulated monocytic colonies (CFU-M) no matter which CSF or CSF combination was used to support them and inhibited granulocytic colonies (CFU-G) if they were generated in the presence of G-CSF. IL-4 antagonized the myelopoietic effects of IFN-gamma: the IFN-gamma-induced suppression of G-CSF-supported CFU-G, as well as the stimulation of CFU-M, were reversed by IL-4. In all cultures, IFN-gamma had a limited, but statistically non-significant, inhibitory effect on CFU-GM, which was not affected by the presence of IL-4. These data show that IFN-gamma and IL-4 reciprocally regulate the generation of myeloid cells involved in humoral (neutrophils) and cellular (macrophages) immune responses through a direct effect on monopotential myeloid progenitor cells.

Synergistic effects of interleukin 4 and interleukin 12 on NK cell proliferation

Our previous studies have demonstrated that interleukin12 (IL-12) (cytotoxic lymphocyte maturation factor/NK cell stimulatory factor) and IL-7 alone have the ability to generate high LAK activity and low proliferative activity in CD56+ NK cells. This study was undertaken to examine the influence of IL-4 on the IL-12-induced activation of CD56+ NK cells. IL-4 did not affect the IL-12-induced generation of LAK activity in CD56+ cells, in contrast to an inhibition of IL-2 and IL-7-induced LAK activity. Most interestingly, the combination of IL-4 and IL-12 resulted in a synergistic proliferative activity (8-fold) in the CD56+ NK cells, and a marked increase in the cell yield at day 5 was detected. Furthermore, the potent effect of IL-4 on IL-12-induced proliferation was restricted to the CD56+ NK cells, as CD56- cell populations were found unresponsive to the combination of IL-4 and IL-12. Furthermore, IL-4 induced a slight increase in the IL-12-stimulated TNF production. IL-12 enhanced the IL-12 receptor (R) expression and IL-4R expression in the CD56+ NK cells. Combined treatment with IL-12 and IL-4 further enhanced the IL-12R expression, most prominently in the CD56+, CD16- NK subpopulation. The increased IL-4R expression induced by IL-12 and the increased IL-12R expression induced by IL-4 may explain the synergistic proliferative activity detected in response to IL-12 and IL-4. IL-4 seems to possess unique stimulatory properties towards resting CD56+ NK cells, when used as a costimulus with IL-12.

Interleukin-4 down-regulates Sendai virus-induced production of interferon-alpha and -beta in human peripheral blood monocytes in vitro

Recombinant interleukin-4 (rIL-4) caused a 65-70% reduction of the interferon-alpha (IFN-alpha) and -beta production induced by Sendai virus (SV) in human peripheral blood monocytes in vitro. Significant inhibition was seen at concentrations as low as 0.1 ng/ml. The rIL-4 also reduced levels of IFN-alpha and -beta mRNA by 60% and 67%, respectively, as well as the frequency of IFN-alpha and -beta mRNA-containing cells by 65% and 54%, respectively. The frequency of IFN-alpha/beta mRNA-containing cells was inhibited by rIL-4 throughout the whole course of induction by SV. IL-4 caused a shift of the grain count distribution towards less heavily labelled cells, suggesting an inhibitory effect of rIL-4 on most IFN-alpha/beta mRNA-containing cells. Antibodies to rIL-4 did not influence the normal IFN-alpha/beta response induced by SV, but abolished the inhibitory effect of the rIL-4. When rIL-4 was added to cells 4 h after start of stimulation by SV, at which time much mRNA has accumulated but little IFN-alpha/beta has been secreted, no inhibition of the IFN-alpha/beta production by rIL-4 was seen. IFN-gamma had only a minor reversing effect on the rIL-4 inhibition, but if cells were precultivated in medium with or without IFN-gamma for 6 h before SV induction, rIL-4 paradoxically enhanced the IFN-alpha/beta response. Our results suggest that rIL-4 inhibits an early step of IFN-alpha/beta induction in monocytes, at the level either of transcription of IFN-alpha/beta genes or of the processing or stability of mRNA. The IL-4 effects may however depend on the state of activation of the monocytes.

An investigation of factors influencing the in vitro induction of LAK activity against a variety of human bladder cancer cell lines

We investigated the sensitivity of transitional cell carcinoma cells, derived from the human bladder, to lymphokine activated killer cells. Recombinant interleukin-2 activated peripheral blood mononuclear cells were studied for their ability to mediate the cytolysis of a panel of four established human bladder transitional cell carcinoma cell lines. Lymphokine activated killer activity was assessed using a standard four hour chromium release assay. All four bladder cancer cell lines proved to be susceptible to lymphokine activated killer mediated cytolysis. This was found to be dependent upon the dose of cytokine and upon the duration of the activation period. The four cell lines were differentially susceptible to lysis (specific cytotoxicity at effector to target ratio of 40:1; RT112 = 22.9%, RT4 = 49.2%, MGH-U1 = 49.1%, EJ18 = 62.3%). The varying susceptibility of lymphokine activated killer mediated cytotoxicity was found to be independent of the histological grade of the parent tumour or the donor of effector cells. Both interferon-alpha and tumour necrosis factor-alpha also elicited lymphokine activated killer cell activity, although the maximum specific cytotoxicity achieved was considerably lower than that obtained with interleukin-2 alone. Interleukin-2, at optimal concentration, and tumour necrosis factor-alpha were found to behave synergistically in the generation of lymphokine activated killer effectors. However, concentrations of tumour necrosis factor-alpha higher than 100 Uml.-1 resulted in a decrease in specific cytotoxicity. These findings suggest a possible use of adoptive immunotherapy in human bladder cancer and indicate the optimum conditions for the generation of such effector cells.

Characteristics of interleukin-6-enhanced lymphokine-activated killer cell function

To study the effect of IL-6 on the development of cytotoxic cells, we examined lymphokine-activated killer (LAK) activity generated from human nonadherent PBL. Addition of rIL-6 at the initiation of 5-day PBL cultures significantly increases LAK activity in the presence of low concentrations (between 5 and 25 u/ml) of rIL-2. RIL-6 alone induces no PBL LAK activity but at doses as low as 0.8 u/ml rIL-6 enhances LAK activity with optimal enhancement of LAK at 5.0 u/ml of rIL-6. This enhancement is independent of effects on cells growth as rIL-6 did not affect the cell recovery of PBL cultured in rIL-2. RIL-6-enhanced LAK is mediated by the same type of effector cells as those of LAK from rIL-2 alone with effector cells primarily generated from large granular CD3-negative E rosetting lymphocytes. RIL-6 does not change the time course of LAK development and pretreatment of PBL with rIL-6 has no effect on the PBL response to subsequent rIL-2 induction of LAK. Addition of rIL-6 to LAK cultures 2 hr before the cytotoxicity assay shows equal enhancement as addition at the initiation of the culture. However, rIL-6 requires the presence of both rIL-2 and another factor in the supernatant from LAK cultures in order to enhance LAK. Our results indicate that IL-6 can modulate LAK activity at a very late stage of LAK development, and that the enhancement by IL-6 is dependent on the presence of IL-2 and another soluble factor generated during rIL-2 culture.

The effects of staphylococcal protein A on human lymphokine-activated killer cell induction

Staphylococcal protein A (Cowan strain; SpA), a biologically active molecule capable of inducing augmented natural killer (NK) cell cytotoxicity, was studied in regard to its effects on lymphokine-activated killer (LAK) cell development. SpA, when co-cultured with interleukin-2 (IL-2) for 4 days, significantly augmented both LAK activity against NK-resistant M14 (melanoma) target cells and DNA synthesis of peripheral blood mononuclear cells (PBMC). This enhancement occurred with SpA concentrations of 1-100 micrograms/ml in a dose-dependent fashion; concentrations above 100 micrograms/ml were no more effective. When SpA (10 micrograms/ml) was added to PBMC cultures with various IL-2 concentrations, cytotoxicity was increased over controls with IL-2 alone. The peak cytotoxic effect reached a plateau at 80 U/ml IL-2. SpA alone induced early (day 1) cytotoxicity, which rapidly declined. SpA alone did not induce PBMC proliferation but it did increase expression of CD25 (Tac), IL-2 receptor alpha chain, on CD56(Leu19)-positive and -negative cells. The potentiating effect of SpA was significantly enhanced in serum-free medium. If either human AB serum or human IgG was added to cultures SpA-enhanced LAK cytotoxicity was diminished. The addition of anti-interferon gamma (anti-IFN gamma) antibody, but not anti-IFN alpha, inhibited (SpA+IL-2)-induced cytotoxicity, indicating that IFN gamma is partially responsible for the additive cytotoxic effect.