Natural cytotoxicity and antibody-dependent cytotoxicity in solid tumor cancer patients: regulation by adherent cells

Anti-tumor immunity and mechanism of immunosuppression mediated by tumor cells: role of tumor-derived soluble factors and cytokines

The immune system plays a crucial role in the protection against tumor growth and progression. However, the activation of the immune system against the neoplastic cells does not always occur and, therefore, tumor cells are able to grow and progress continually in the host. It has now been realized that tumor cells themselves produce many of the important factors that are responsible for dismounting of effective immune response. These tumor-derived soluble factors invariably subdue the functions of almost every immune cell population. Therefore, we attempted to underline the mechanism of anti-tumor immune response and immunosuppression induced by tumor cells.

Flow cytometric study of lymphocyte subsets in patients at different stages of colorectal carcinoma

PURPOSE

The evaluation of lymphocyte subsets by using monoclonal antibodies in neoplastic patients has provided different results, partly in relation to the stage of the disease. Therefore, as a preliminary study of cancer patients treated with immunomodulating drugs, an analysis of lymphocyte subsets was performed in colorectal carcinoma patients.

METHODS

In this study, a flow cytometric evaluation of lymphocyte subsets was performed in 33 patients affected by colorectal carcinoma, with or without metastases.

RESULTS

A significant reduction of hemoglobin concentrations and hematocrit was observed in all of these subjects, associated with an evident increase of white blood cells, platelets, and HLA DR-positive T lymphocytes, whereas CD 3-CD 4-positive and CD 20-positive lymphocyte concentrations were decreased. Subjects without metastases showed an evident decrease of hemoglobin concentrations and an increase of white blood cells, platelets and CD 3-HLA DR-positive lymphocytes, while patients with disseminated disease also had reduced mean values of hematocrit, red blood cells, CD 3-CD 4-positive, and CD 20-positive lymphocytes.

CONCLUSIONS

The main differences between colorectal carcinoma patients with or without metastases were represented by a decrease of red blood cells, CD 3-CD 4-positive, and CD 20-positive lymphocyte concentrations in the latter group.

The relationship of chemotherapeutic and endocrine intervention on natural killer cell activity in human breast cancer

Peripheral blood natural killer (NK) activity against K562 target tumor cells was monitored in patients with breast cancer receiving no treatment, combination chemotherapy, and/or endocrine therapy. NK activity in untreated Stage I patients with no evidence of disease (ned) was significantly higher than in healthy controls. NK activity was shown to decline in individuals with cytotoxic drug therapy (P equals 0.036). There also were reduction in lymphocyte recoveries concomitant with chemotherapeutic intervention (P less than 0.001). Lymphocyte counts were incorporated in a calculation of absolute NK activity that more accurately reflected the significant reduction in NK activity that occurred in patients with localized and systemic disease on chemotherapy. Different chemotherapeutic agents were found to selectively affect NK activity. Stage II patients on phenylalanine mustard (P)/5-fluorouracil (F) (PF) and cyclophosphamide (C)/methotrexate (M)/5-fluorouracil (F) (CMF) protocols showed significant reductions in overall NK activity relative to healthy controls and Stage I patients with ned. Patients on P/doxorubicin (A)/F/tamoxifen (Tx) (PAFT) protocols showed reduced NK activity relative to Stage I patients. Patients on the short-dose C/A (CA) protocol showed normal levels of overall NK activity. High-risk Stage I patients on methotrexate (M)/F (MF)with sequential leucovorin rescue and patients with metastatic disease on endocrine therapy, i.e., Tx or megestrol acetate (Meg) showed overall NK activities in the range of healthy controls. Patients with systemic disease on CMF, CMF/vincristine/prednisone (CMFVP), vinblastine/A/thiotepa/fluoxymesterone (VATH), mitomycin/mitoxantrone (MtMx), and A regimens showed overall levels of absolute NK that were significantly less than either healthy controls or metastatic patients undergoing endocrine therapy. NK cytolytic data, monitored at multiple effector to target ratios, were subjected to exponential regression analysis. The elevation of NK cell responses in Stage I patients with ned and the decline of NK cell responses with cytotoxic chemotherapy were due to alterations in the maximal plateau levels of NK cell cytotoxicity represented by the A (asymptote) values. The k values obtained on regression analysis and indices of the relative killing capacities of individual NK cells remained unaltered in all populations. These results suggest that the cytolytic lymphocyte NK pool, elevated in Stage I patients with cancer, selectively declines as a result of cytotoxic therapy.

Natural killer cell function in children with malignant solid neoplasias

Natural killer (NK) cell numbers and lytic activity were determined in 40 children with various types of solid malignant neoplasias and in 25 control children by NKH-1 monoclonal antibody and cytotoxicity against K562 target cells, respectively. Patients were analyzed at the time of diagnosis before initiation of therapy and followed over a median time of 15.8 months. Mean NK cell numbers and lytic activity were similar among different types of tumor analyzed. Patients with localized disease (stages I, II; n = 25) also showed values not statistically different from those of patients in advanced disease (stages III, IV; n = 15). According to their response to therapy, patients were divided into three groups: group 1 (complete remission; n = 28), group 2 (partial remission; n = 5), and group 3 (progression of disease; n = 6). Patients in group 3 showed at the time of diagnosis a mean NK activity significantly lower than that of patients in groups 1 and 2 and control children (P = 0.007). The defect in NK cell lytic capacity in vitro observed in patients with progressive disease suggests that NK cells play a role in the control of neoplastic growth in vivo and may imply that some children with refractory progressive disease can benefit from immunomodulation destined to improve the lytic potential of NK cells.

The in vitro development of cytotoxicity in response to granulocyte/macrophage-colony-stimulating factor or interferon gamma in the peripheral blood monocytes of patients with solid tumors: modulation by arachidonic acid metabolic inhibitors

The capacity of granulocyte/macrophage-colony-stimulating factor (GM-CSF) and interferon gamma (IFN gamma) to elicit monocyte cytotoxicity in vitro in the peripheral blood monocytes of patients with solid tumors was investigated. The cytotoxicity elicited by IFN gamma was significantly reduced in cancer patient monocytes compared to normal monocytes. The cytotoxicity elicited by GM-CSF, however, was comparable between cancer patient monocytes and normal monocytes, but was lower than that induced by IFN gamma. Indomethacin, a cyclooxygenase inhibitor, significantly augmented IFN gamma-elicited cytotoxicity in cancer patient monocytes, but not in normal monocytes. In contrast, indomethacin augmented GM-CSF-elicited cytotoxicity in both cancer patient monocytes and normal monocytes. Nordihydroguaiaretic acid (NDGA), a lipoxygenase inhibitor, was found to suppress cytotoxicity in response to IFN gamma and GM-CSF in both cancer patient monocytes and normal monocytes. The addition of leukotrienes to NDGA-treated cultures restored the development of cytotoxicity. Thus there are differences in the in vitro response of cancer patient monocytes and normal monocytes to distinct biological activators. Furthermore, these responses can be manipulated by agents that modulate arachidonic acid metabolism.

Alterations of rat natural killer (NK) cell cytotoxicity and cytokine production by 3-methylcholanthrene (3-MC)

The carcinogen 3-methylcholanthrene (3-MC) was found to exert immunosuppressive effects both in vitro and in vivo in this study. Spleen cells from 8-week-old male, Sprague-Dawley (S-D) rats exposed to 1, 10 or 100 micrograms/ml 3-MC in vitro for 18 h exhibited a dose-dependent decrease in natural killer (NK) cell cytotoxicity against the YAC-1 tumor target cells in a 4 h 51Cr-release assay. Peritoneal macrophage production of prostaglandin E2 (PGE2) was significantly decreased at all three 3-MC concentrations following a 24 h exposure in vitro. No effect of 3-MC on splenic interleukin-2 (IL-2) production was observed. A separate group of rats was inoculated with a single subcutaneous dose of 5 or 10 mg 3-MC and cytotoxic activity of spleen NK cells was examined at 1, 2, 3, 7, 14, 21, 28, 60, 120 and 180 days after the 3-MC injection. Natural killer cell cytotoxicity was suppressed as early as 24 h after 3-MC injection and persisted up to 21 days. This decrease in NK activity was accompanied by a decreased production of splenic interferon and elevated production of PGE2 by peritoneal macrophages. Natural killer cell cytotoxicity was elevated in the 3-MC-treated rats at 28 and 60 days post-treatment. At 120 and 180 days post-3-MC treatment, when the rats were bearing palpable chemically-induced tumors, NK activity was again significantly depressed. In addition, 3-MC-induced tumors were surgically removed and cultured in vitro. Supernatants from these tumor cell lines were shown to markedly inhibit NK cytotoxicity when tested in vitro. Preliminary results indicate that this inhibition may be mediated by prostaglandins.

Natural killer cells in children with malignant solid tumors. Effect of recombinant interferon-alpha and interleukin-2 on natural killer cell function against tumor cell lines

Natural killer (NK) cells and NK cell activity were determined in three groups (newly diagnosed [n = 21], on therapy [n = 21], and off therapy [n = 18]) of children with various types of malignant solid tumors and in a control group (n = 26) by means of Leu-7 and Leu-11b monoclonal antibodies and a 4-hour 51Cr-release assay, respectively. The erythroleukemia cell line K562 was used as a target cell. The newly diagnosed group included eight patients with localized disease (Stage I-II), ten with bulky but nonmetastatic disease (Stage III), and three with metastases (Stage IV). The mean percent of NK cell activity in the newly diagnosed group was significantly higher than that of the control group. Children with Stage III tumors at diagnosis had higher mean NK cell function than those with Stage I-II and Stage IV. On therapy patients had significantly fewer NK cells and lower NK cell cytotoxicity than those in the other groups studied. We also studied the following: (1) the in vitro effect of recombinant interferon-alpha (rIFN-alpha) and recombinant interleukin-2 (rIL-2) on NK cell function of peripheral blood lymphocytes (PBL) from children with solid malignancies; and (2) the susceptibility of neuroblastoma-derived (CHP-126 and SKNSH) and rhabdomyosarcoma-derived (A-204) cell lines to NK cell lysis. Both rIFN-alpha and rIL-2 enhanced NK cell activity of PBL from children with malignancies and healthy children against K562 and solid tumor cell lines. The enhancing effect or rIL-2 was greater than that of rIFN-alpha. CHP-126 and SKNSH cell lines were susceptible to NK cell lysis mediated by the PBL of children with neuroblastoma and the control group. The A-204 cell line was less sensitive than K562 to NK cell cytotoxicity. Our results suggest a potential therapeutic role for both cytokines in the treatment of malignant solid tumors of childhood.

Natural killer cell activities of patients with breast cancer against different target cells

Natural killer (NK) cell activity against K 562 erythroleukemic- and MCF-7 breast carcinoma-derived cells was monitored in short-term (3 h/K 562) and long-term (18 h/MCF-7) chromium release tests for 60 patients with untreated primary breast disease. Target cell lysis was the same for patient groups with benign (n = 13) and malignant (n = 47) breast disease (27% versus 36% mean chromium release; target:effector ratio 40:1 for K 562 and 28% versus 40% for MCF-7 cells). NK activity as defined by short-term lysis of K 562 cells did not correlate with MCF-7 cell lysis in long-term assays for the carcinoma patients. This functional heterogeneity of natural cytotoxic activities of breast cancer patients was confirmed by a different age distribution for K 562 and MCF-7 cell lysis and high levels of MCF-7-directed NK activity in the grade I tumor group (56.2%). Our results indicate that measurement of peripheral blood NK activity against a breast carcinoma-derived cell line (MCF-7) defines a disease-related natural cytotoxic activity which correlates better with prognostic tumor parameters (tumor grading) than NK activity as defined by the lysis of K 562 erythroleukemic cells. NK activity testing against breast carcinoma cell lines should be used to monitor natural cytotoxic activities in breast cancer patients and its modulation by different routes of treatment.

Differential surface marker expression in patients with CD-16+ lymphoproliferative disorders: in vivo model for NK differentiation

In this study, we report on three patients, each with a CD-16+ lymphoproliferative disorder. Peripheral blood lymphocyte from all three patients were evaluated for lymphocyte morphology, natural killer (NK) function, and surface marker expression. In addition, two-color flow cytometric analysis was performed to determine the phenotype of the CD-16+ cells. Our findings indicate that the presence of increased numbers of CD-16+ cells alone is not a good predictor of NK activity. However, we observed a differential expression of the HLA class II molecules DR and DQ on the CD-16+ cells obtained from these patients that was associated with NK function. Hence, a CD-16+, Leu-7-, Leu-19+ (NKH-1A) and HLA class II+ phenotype did correlate with NK function in contrast to a CD-16+, Leu-7+, Leu-19- (NKH-1A) and HLA class II- phenotype. Of importance was the fact that the CD-16+, HLA class II+ cells did not express CD-25 or TFR, nor did they mediate cytotoxicity against solid tumor targets, suggesting that these CD-16+ cells are not activated. Thus, in contrast to previous studies of NK ontogeny that utilized in vitro activated NK cells, studies of patients with CD-16+ lymphoproliferative disorders may provide an alternative approach for examining NK differentiation.

Peripheral blood natural killer cell activity in human breast cancer patients and its modulation by T-cell growth factor and autologous plasma

The role of clinical status and chemotherapeutic intervention on native and inducible natural killer cell (NK) activity in breast cancer was ascertained by determining the K562 cytotoxicity capacity of peripheral blood lymphocytes. The level of NK activity in breast cancer patients receiving chemotherapy (n = 62) was significantly lower than that observed in patients currently receiving no treatment (n = 56) (at effector: target [E:T] ratios of 20:1, 10:1, and 5:1, 23.8%, 17.9%, and 12.1% versus 34.9%, 25.6%, and 15.9%, respectively; P less than 0.01, two-way analysis of variance). The absolute level of NK activity in peripheral blood of cancer patients on therapy was further reduced when compared with untreated patients and healthy controls when reductions in lymphocyte counts concomitant with chemotherapeutic intervention were included in calculations of NK activity. T-cell growth factor (TCGF) increased NK activity in all breast cancer patients and healthy controls with maximal stimulation of basal activity at a concentration of 10% (volume/volume [v/v]) TCGF. The percent stimulation of basal NK activity by TCGF was significantly greater in patients receiving chemotherapy (26.4%, 24.3%, and 19.0% at an E:T of 20:1, 10:1, and 5:1, respectively; n = 23) than in untreated patients (16.6%, 18.5%, and 18.9%; n = 21) and healthy controls (23.5, 18.6, and 8.1; n = 8) (P less than 0.05 and P less than 0.01, respectively, two-way ANOVA). The influence of soluble factors and agents in serum on peripheral blood NK activity was assessed by monitoring the effects of autologous plasma on basal and TCGF-stimulated NK activity. Autologous plasma at concentrations less than or equal to 10% (v/v) enhanced basal NK activity. Levels of inducible NK activity in the presence of either 10% TCGF, 5% plasma, or a combination of both were not significantly different in statistical comparisons of both the effects of inducer and therapeutic modality. At concentrations of plasma greater than 10% (v/v), progressively decreasing NK activities were observed. T-cell growth factor could partially reverse the inhibitions of NK activity by 25% autologous plasma. In 13 experiments, basal NK activity and NK activity in the presence of 10% TCGF, 25% autologous plasma, and a combination of TCGF and plasma were 27.6%, 46.0%, 16.3%, and 28.1%, respectively (E:T = 20:1). This study indicates that NK function is compromised in breast cancer patients receiving cytotoxic drug-therapy. The potential use of TCGF in adjuvant immunotherapy as a modulator of NK function has been demonstrated.(ABSTRACT TRUNCATED AT 400 WORDS)

Abnormal monocyte function in patients with Kaposi's sarcoma

Monocyte-mediated functions were evaluated in the peripheral blood mononuclear cells (PBMC) of 11 previously untreated patients with Kaposi's sarcoma in association with the acquired immune deficiency syndrome (KS/AIDS). All patients had lymphadenopathy, an abnormal OKT.4/OKT.8 ratio, and a good performance status; none had clinically apparent infections at the time of testing. Monocyte functional assessments included immunoregulatory activity in phytohemagglutinin-stimulated (PHA) lymphoblastogenesis assays, natural killer (NK) assays, Interleukin 2 (IL2) production assays and, quantitation of opsonized zymosan-induced chemiluminescence responses. A group of seven hemophilia patients who had been receiving concentrated blood products and who presented with evidence of an abnormal OKT.4/OKT.8 ratio were also investigated as controls. As a group, the patients with KS/AIDS had a significantly depressed response to PHA compared with normal control subjects and patients with hemophilia; this was significantly elevated by indomethacin or by the removal of glass adherent cells. PBMC from KS/AIDS patients also had an impaired ability to produce IL2 in PHA-stimulated cultures which was enhanced by the addition of indomethacin. NK function was also suppressed in both groups of patients, but could not be augmented by the removal of glass adherent monocytes. Chemiluminescence responses to opsonized zymosan were variable, but found to be significantly different from normal in the majority of patients studied. These results demonstrate that monocyte function can be abnormal in patients with KS/AIDS and might contribute to some of the immunologic impairment seen in these patients.

Kinetic analysis of the inhibition of natural killer (NK) activity by multiple populations of tumor-activated suppressor cells

Previous studies have shown that the progressive growth of the M-1 fibrosarcoma in DBA/2J mice is associated with the activation of suppressor cells which inhibit both mitogen-induced proliferative responses and antibody synthesis. In this study, we have analyzed the effect of tumor growth on NK cell activity. Mice in the advanced stages of tumor growth did have a significant depression in NK activity, and this depression could not be overcome by the injection of the interferon inducer, polyinosinic-polycytidylic acid (Poly I:C). The decline in NK activity was associated with the presence in the spleens of suppressor cells capable of inhibiting the NK activity of spleen cells from Poly I:C-treated syngeneic mice. In order to characterize the suppressor cells, we used a combination of negative selection procedures and kinetic analysis. These studies demonstrated that the spleens of tumor-bearing mice contained two distinct populations of suppressor cells which were not evident in normal mice. One population was non-adherent to nylon wool, Thy-1-, non-phagocytic, did not bind target cells, and had a non-competitive mechanism of suppression. The second population was adherent, Thy-1-, phagocytic, and had a competitive mechanism of suppression. In addition, the spleens of both normal and tumor-bearing mice contained an adherent, non-competitive suppressor cell population which was enriched following negative selection procedures removing T cells or phagocytic cells.

Effect of chemotherapy on NK function in the peripheral blood of cancer patients

The effects of cytotoxic chemotherapy on NK cell function and on glass adherent cell regulation of NK cell function was evaluated in the peripheral blood mononuclear cells of 20 previously untreated solid tumor patients. Most of the patients studied had lung cancer and received one of four combination chemotherapy treatment regimens. In addition, one patient with colon carcinoma and one patient with melanoma were studied, each of whom received treatment with a single agent. The results demonstrated that chemotherapy exerted a differential influence on NK activity which correlated with the pretreatment NK level of function in the individual patient. In patients with depressed NK levels prior to treatment, chemotherapy augmented NK function; in patients with normal levels prior to treatment, chemotherapy depressed NK function. The effects observed appeared to be associated with the capacity of chemotherapy to influence glass adherent cell regulation of NK activity. There was no apparent correlation between the effects of chemotherapy on numbers of NK effector cells, Leu11+ cells, or latex-ingesting cells. Also, there was no correlation between the effects seen and the type of drug treatment that was administered; rather, this was dependent on the pretreatment NK level of function which in turn was associated with glass adherent cell regulation of NK function.

The relationship of clinical status and therapeutic modality to natural killer cell activity in human breast cancer

The role of clinical status and therapeutic intervention on natural cell-mediated cytotoxicity in breast cancer was ascertained by monitoring natural killer (NK) cell activity in peripheral blood samples. Patients with localized disease on chemotherapy showed significant reductions in NK activity concomitant with reduced lymphocyte numbers, when compared to untreated patients (18.1% versus 32.7%, P less than 0.005). Lymphocyte counts were included in a calculation of the absolute proportion of NK activity that incorporates a correction factor for the leukopenia that occurs as a result of cytotoxic therapy and disease progression. This calculation more accurately reflects the significant reduction of NK activity that occurs in patients with localized and systemic disease on chemotherapy when compared to untreated patients with no current evidence of disease (10.3% and 14.9% versus 30.7%, respectively; P less than 0.001). Different chemotherapeutic regimens were found to selectively affect NK cell function. The levels of both actual and absolute NK activity were significantly reduced in patients receiving 5-fluorouracil and L-phenylalanine mustard; cyclophosphamide, methotrexate, and 5-fluorouracil; and vincristine, Adriamycin (doxorubicin), and 5-fluorouracil, whereas only the levels of absolute NK activity were significantly reduced in patients receiving mitomycin, Megace (megestrol acetate), and Adriamycin when compared to untreated cancer patients. In contrast, tamoxifen-treated patients demonstrated levels of actual and absolute NK activity observed with untreated cancer patients. Patients receiving tamoxifen showed significantly elevated NK activity when compared to patients on all other chemotherapies. These results indicate that monitoring NK cell function may be useful in assessing the immunosuppressive effects of chemotherapeutic intervention.

Changes in the host natural killer cell population in mice during tumor development. 2. The mechanism of suppression of NK activity

Our earlier studies revealed that a rapid and progressive loss of splenic NK activity in mice during the development of a number of transplanted tumors as well as of spontaneous tumors was due to an inactivation of natural killer (NK) lineage cells rather than to their disappearance. The mechanism of this inactivation have now been explored in CBA/J mice receiving transplanted Ehrlich ascites tumors and in C3H/HeJ mice bearing spontaneous mammary tumors or receiving transplants of syngeneic mammary tumor lines of recent origin. A poor activation state or maturation arrest of NK lineage cells due to a low interferon level in vivo was ruled out, since the host NK activity could not be restored after administration of either an interferon inducer poly(I:C) or interferon-alpha, although such treatments enhanced the activity in tumor-free mice by four- to eightfold. Possible presence of host suppressor cells acting on the effector or preeffector stage of NK cells was explored by mixing spleen cells from tumor bearers with normal spleen cells either during the NK assay, or for a 20-hr period of in vitro short-term culture prior to the NK assay. Mixing during the NK assay led to a reduction of NK activity explicable by a simple dilution of active NK cell concentration rather a suppression of active NK cells. On the other hand, a 20-hr coculture of the mixed population at various ratios led to a complete abrogation of the NK activity, indicating that the suppressor cells acted on the preeffector stage of the NK Lineage. A further characterization of suppressor cells revealed that they were (1) contained in the adherent fraction of the spleen of tumor bearers, (2) of monocyte/macrophage morphology, (3) capable of phagocytosing latex particles, and (4) positive for surface Mac-1 antigen, as noted from a radioautographic binding of 125I-labeled monoclonal anti-Mac-1 antibody. The mechanism of the suppression was identified, at least in part, as being mediated by prostaglandin-like molecules, since the presence of indomethacin, a prostaglandin-inhibitor, during the 20-hr coculture period completely abrogated the suppression. Indomethacin exerted no direct effect on the recruitment or killer activity of NK lineage cells in vitro. NK cell suppression may be another normal immunoregulatory mechanism which alters the host-tumor balance in favor of the tumor rather than the host.

Natural killer cells

It is proposed that this article will encompass a review of primarily the human natural killer cell. The following parameters of the human natural killer (NK) cell will be reviewed: its ontogeny; surface membrane characteristics including monoclonal antibody reactivity, cell lineage, the natural killer sensitive targets, and the proposed mechanism of action of natural killer cells cytotoxicity against these NK sensitive targets; the status of natural killer cell in relationship to clinical disease; the alteration of natural killer cells both in vitro and in vivo; and finally postulate relevance of the natural killer cell in context of the evolution or pathophysiology of human disease. There will be an attempt through this review to encompass the more recent publications that pertain to the various sections.

Regulation of NK cell activity by prostaglandin E2: the role of T cells

The influence of T cells on the production of prostaglandins (PGE2) and on PGE2-mediated regulation of natural killer (NK) activity was studied. Supernatants from peripheral blood mononuclear cells (PBMC) and from PBMC depleted of T cells ((PBMC)-T), both of which had been incubated in plastic petri dishes overnight, contained similar amounts of PGE2, as detected by radioimmunoassay and by their potential to inhibit NK activity of peripheral blood mononuclear cells in a 51Cr release assay with K 562 cells as the target population. However, the NK activity of PBMC was inhibited significantly more strongly (P less than 0.005) by PGE2-containing supernatants than was the NK activity of (PBMC)-T. In further assays, in which synthetic PGE2 in concentrations of 10(-4) and 10(-5)M was added, a significant inhibition of NK activity was observed in PBMC populations (P less than 0.05), but not in (PBMC)-T. Thus, T cells did not seem to be involved in the control of PGE2 production, but their presence was necessary for PGE2-mediated inhibition of NK activity.

Monocyte-mediated-antibody-dependent cellular cytotoxicity in malignant lymphoma and solid tumors

Monocyte-mediated-antibody-dependent cellular cytotoxicity (MO-ADCC) was studied in 21 patients with Hodgkin's disease (HD), 15 patients with a long-lasting remission of HD, 11 patients with non-Hodgkin's lymphoma (NHL), 11 patients with solid tumors, and 15 normal controls. Lymphocyte ADCC (LY-ADCC) was evaluated in 12 patients with HD and 9 normal controls. Monocytes lymphocytes were isolated with cell-scatter monitored counterflow centrifugation providing high purity and yield. Antibody-dependent cellular cytotoxicity was evaluated by means of DNA flowcytometry, using antibody-coated chicken erythrocyte targets (CRBC). In comparison with normal controls MO-ADCC was significantly increased in HD (P less than 0.0005), NHL (P less than 0.005), and solid tumors (P less than 0.005). In patients in long-lasting complete remission of HD, MO-ADCC was in the normal range. Lymphocyte-ADCC of 12 patients with HD was similar to that of 9 normal controls. In all experiments LY-ADCC was invariably lower than MO-ADCC of the same donor, indicating the monocyte as the most potent effector cell towards CRBC targets. Results indicate the following: (1) purified cell suspensions of both lymphocytes and monocytes are essential to unravel their role as effector cells; (2) LY-ADCC in HD is similar to normal controls; (3) MO-ADCC enhancement is not uncommon in malignant lymphoma and several solid tumors; (4) normal MO-ADCC in a group of successfully treated patients with HD suggests a disease-related induction of enhanced MO-ADCC.

Prospective study of natural cytotoxicity in peripheral blood of patients with nonlymphoid solid malignancies

Natural killer (NK) cells have been implicated as an initial immunosurveillance mechanism for carcinogenesis in humans. Work in the murine system as well as the findings of depressed NK activity in patients with advanced malignancies and the discovery of increased incidences of cancer in humans congenitally deficient in NK ability have supported this. Few prospective studies have demonstrated a prognostic change in NK activity with respect to malignant disease course. In 32 healthy donors, NK activity against K562 was determined. No race or sex difference existed with respect to NK cell function. Esophageal (5), bronchogenic (3), breast (3), cervical (3), and endometrial (1) cancer patients who had received no prior chemotherapy were compared to controls. All patients subsequently received radiotherapy. Prior to such treatment NK activity could not be associated with stage of malignancy. Of the 15 patients studied, 11 were sequentially followed. Five of eight patients with stable or improving clinical courses as assessed by weight and Karnofsky scores were found to have increasing NK activity. Two of three patients with poor clinical courses presented with subnormal killing which never rose to normal while the third declined to subnormal before expiring. Esophageal, cervical, and endometrial carcinoma patients all presented with low or subnormal NK activity. Of these, only cervical and endometrial cancer patients exhibited an increase to normal levels.

The biology of the human natural killer cell

Natural killer (NK) cells in the human are a population of large granular lymphocytes (LGL) with at least one unique surface antigen not expressed on cells of other lineages. NK-target-cell interaction appears to involve carbohydrate recognition and, following binding, the NK cells are induced to generate O2-, transmethylate membrane phospholipids, and activate phospholipase A2. Some or all of these activities trigger a cascade of events which ultimately leads to the secretion of a substance toxic to the target cell. A variety of genes controls various steps in this cytolytic pathway. There is a good deal of evidence in the mouse, and some in the human, that NK cells play a role in host surveillance against tumor development, resistance to viral infections, and, possibly, hematopoietic regulation.