Human bronchoalveolar macrophage cytotoxicity for cultured human lung-tumour cells

Augmentation of impaired tumoricidal function in alveolar macrophages from lung cancer patients by cocultivation with allogeneic, but not autologous lymphocytes

It has been reported that the in vitro development of tumoricidal function in alveolar macrophages from lung cancer patients is reduced significantly when compared to that in peripheral blood monocytes from the same patients or alveolar macrophages from control patients. In the present investigation, a method for potentiating the development of tumoricidal function in alveolar macrophages from lung cancer patients is described. This method, which relies on priming the macrophages with purified, allogeneic peripheral blood lymphocytes from normal donors, could not be demonstrated when autologous lymphocytes from lung cancer patients were used in the priming coculture. The augmentation of tumoricidal function appears to be mediated by one or more soluble factors, since supernatants from cocultures of alveolar macrophages and allogeneic peripheral blood lymphocytes could enhance the cytotoxic function of freshly obtained alveolar macrophages. Furthermore, it appears that NK cells are necessary for this effect, since depletion of CD56+/CD57+ cells from allogeneic lymphocytes eliminated their capacity to enhance alveolar macrophage cytotoxic function. The augmentation of cytotoxic function elicited in alveolar macrophages by this method was not associated with changes in the secretion of tumor necrosis factor alpha, or interleukin 1 beta.

Modulation of tumoricidal function in alveolar macrophages from lung cancer patients by interleukin-6

Previous studies have demonstrated that alveolar macrophages from lung cancer patients are impaired in their ability to develop tumoricidal function when stimulated by activators such as interferon gamma + lipopolysaccharide. However, these same macrophages have been shown to develop significant tumoricidal function when precultured with macrophage-depleted allogeneic peripheral blood lymphocytes from normal donors, an effect that was lost by the elimination of natural killer cells from the allogeneic lymphocyte population. In the present study, the effect of each activation condition on the expression of mRNA for interleukin-1 alpha (IL-1 alpha), IL-1 beta, tumor necrosis factor alpha (TNF alpha) and IL-6 was determined using reverse transcription/polymerase chain reaction. The results show that the non-permissive activation condition is associated with the expression of mRNA for IL-6 while the permissive activation condition is not. Antibodies against IL-6 were subsequently shown to permit the development of tumoricidal function in alveolar macrophages stimulated with interferon gamma + lipopolysaccharide while IL-6 protein was shown to inhibit the stimulatory action of allogeneic lymphocytes on the development of tumoricidal function in the same alveolar macrophages. Neither the permissive (i.e. allogeneic lymphocyte stimulation) nor the non-permissive (i.e. interferon gamma + lipopolysaccharide) activation condition had any effect on the capacity of alveolar macrophages from lung cancer patients to express mRNA for IL-1 alpha, IL-1 beta or TNF alpha. These results show that IL-6 can regulate the ability of alveolar macrophages from lung cancer patients to be stimulated by interferon gamma + lipopolysaccharide to develop significant tumoricidal function. They also show that allogeneic lymphocytes have the capacity to down-regulate IL-6 mRNA synthesis by alveolar macrophages thereby permitting the development and/or expression of macrophage tumoricidal function.

Bronchogenic carcinoma: immunologic aspects

Evidence that host immunologic function may influence the behavior of lung cancer is accumulating. Non-small-cell lung cancers are heavily infiltrated by host lymphocytes. The fact that monoclonal antibodies have been developed against lung cancer cells implies that such cells express surface antigens and are therefore vulnerable to immune recognition. Failure of the host defense mechanism to control tumor growth may involve (1) reduced natural killer cell activity, (2) inadequate lymphokine-activated killer cell function, or (3) tumor secretion of immunomodulating factors. Basic immunologic research studies of lung cancer are increasing the potential for clinical applications. New monoclonal antibodies have improved both the sensitivity and the specificity of immunohistopathologic analyses of pulmonary specimens. Links between immune function and prognosis in patients with lung cancer have been established. Finally, initial results from protocols that have used tumor-infiltrating lymphocytes, interleukin 2, and tumor vaccines suggest that immunobiologic treatment modalities may be increasingly applicable in patients with lung cancer.

Tumor-infiltrating lymphoreticular cells. Histologic and immunohistologic investigations performed on metastasizing squamous cell carcinomas of the head and neck

Ten squamous cell carcinomas of the head and neck region and metastatic deposits in 41 cervical lymph nodes were investigated histologically and immunohistologically to determine the cellular immune response to the tumors, particularly the localization and phenotype of the tumor-infiltrating lymphoreticular cells. The lymphoreticular cells were accumulated preferentially in the stroma in and around the tumor. The foci of neoplastic cells usually contained smaller numbers of lymphoreticular cells. Lymphocytes and macrophages that lay in close contact with malignant cells did not exert histologically apparent signs of toxic effects on these cells. Macrophages (Ki-M6+) nearly always constituted the largest fraction of the lymphoreticular cells, but T-lymphocytes (Leu-1+), T4-cells (Leu-3a+), and plasma cells were also often observed in large numbers. T8-lymphocytes (Leu-2a+) and T-accessory cells (Leu-6+) most often occurred in moderate numbers. Leu-6+ cells represented the only cell type found predominantly in the atypical epithelial complexes. All other cells investigated, i.e., B-lymphocytes (To15+), B-accessory cells (Ki-M4+), natural killer cells (Leu-7+), eosinophils, and tissue mast cells were usually encountered only in very small numbers of were virtually absent from the lymphoreticular infiltrates. A comparison of the cellular reaction in the primary tumors and their corresponding cervical lymph node metastases revealed differences for T8-lymphocytes, T4-cells, and T-accessory cells. Although T8-lymphocytes were more numerous in both the stroma and tumor foci of the metastases than in the primary tumors, T4-cells and T-accessory cells were present in greater numbers only in the tumor foci of the metastases. The preferential localization of tumor-infiltrating lymphoreticular cells in the tumor stroma and the absence of a visible cytotoxic effect of lymphocytes and macrophages in direct contact with tumor cells support the hypothesis of a deficient immune response to clinically detectable squamous cell carcinomas of the head and neck region.

Impaired tumoricidal function of alveolar macrophages from patients with non-small cell lung cancer

The capacity of alveolar macrophages and peripheral blood monocytes from patients with non-small cell lung cancer to develop tumoricidal function after in vitro stimulation with different macrophage activators was investigated. Alveolar macrophages were found to be impaired in their ability to develop cytotoxic activity compared with either the peripheral blood monocytes from the same patients or alveolar macrophages from patients with nonmalignant lung disorders. This result was observed consistently under diverse culture conditions and with different macrophage activators including gamma-interferon (gamma-IFN), granulocyte-macrophage colony-stimulating factor (GM-CSF), phorbol myristate acetate, or endotoxin. The impairment in tumoricidal function observed in alveolar macrophages was not associated with reduced target cell binding compared to peripheral blood monocytes. Alveolar macrophages from patients with lung cancer were found to secrete significantly greater amounts of tumor necrosis factor (TNF) and interleukin-1 (IL-1) than either peripheral blood monocytes from the same patients or alveolar macrophages from the patients with nonmalignant disorders. These results are consistent with either different regulatory pathways for cytotoxicity and cytokine secretion in the alveolar macrophages of patients with lung cancer or diversity in the subpopulations of cells responsible for these functions.

Defective cytostatic activity of pulmonary alveolar macrophages in primary lung cancer

Macrophages are thought to play an important immune effector cell role in antitumor host defense. It remains unclear whether PAM antitumor activity in patients with lung cancer is normal or impaired. We examined PAM cytostasis in patients with lung cancer and in control subjects and determined whether the in vitro PAM response could be enhanced by gamma-interferon. Nineteen patients with primary lung carcinoma and 15 control patients underwent BAL. Five patients with cancer underwent lavage of both lungs to assess whether any abnormality found related to tumor proximity or was part of a more generalized defect. Cytostatic activity was assessed by measuring inhibition of incorporation of tritiated thymidine into the target cell U937. There was a significant difference in baseline cytostatic activity between patients with cancer (mean +/- SE, 59 +/- 7 percent) and control patients (92 +/- 2 percent) (p less than 0.0002). The increase in cytostatic function after stimulation with gamma-interferon (1,250 units/ml) was higher in the group with cancer (28 +/- 5 percent increase from baseline) than in controls (5 +/- 1 percent) (p less than 0.0005). Cytostasis after stimulation was not significantly different between the groups. In the bilaterally lavaged group, baseline cytostatic activity was not different between cancerous and noncancerous lungs and was again significantly lower than in control subjects. These results indicate (a) that PAM baseline cytostatic activity in patients with cancer is lower than in controls, (b) that gamma-interferon can significantly augment cytostatic function in patients with cancer, to levels comparable with those achievable in control patients, and (c) that the PAM abnormality is part of a generalized immune defect in lung cancer and does not simply reflect a local response to the carcinoma. It may be inferred from these results that PAMs from patients with primary lung cancer are not fully stimulated in vivo and that a defect of T cell lymphokine production may underlie the macrophage dysfunction.

Production of tumor necrosis factor-alpha by alveolar macrophages of lung cancer patients

The abilities of human alveolar macrophages (AM) obtained from healthy donors and patients with lung cancer to produce tumor necrosis factor (TNF) were compared with those of their blood monocytes after activation with lipopolysaccharide (LPS). TNF activity was assayed by measuring cytotoxicity against actinomycin D-treated L929 cells and TNF was determined quantitatively by sandwich enzyme-linked immunosorbent assay (ELISA) with polyclonal and monoclonal antibodies against TNF-alpha. Unstimulated AM from healthy donors released variable amounts of TNF spontaneously, whereas blood monocytes did not. When treated with LPS for 24 h, AM and monocytes produced TNF dose-dependently, but TNF production by AM was significantly more than that by blood monocytes. This TNF activity was inhibited completely by monoclonal anti-TNF-alpha antibody. Macrophages generated by in vitro maturation of monocytes induced by granulocyte-macrophage colony-stimulating factor (GM-CSF) produced more TNF than freshly isolated monocytes. No difference was found in the abilities of AM from healthy donors and patients with lung cancer to produce TNF after activation stimuli. These observations suggest that human AM may be important in in vivo antitumor defense of the lung through TNF-alpha production.

Assessment of phagocytic function using chemiluminescence

Chemiluminescence is a simple and reliable method of assessing phagocytic function. The bactericidal properties of phagocytes are dependent on the production of powerful oxidising species by the respiratory burst. These reactive oxygen radicals react with biological substrates to form excited compounds which then relax to their ground state by photon emission. This energy release is in the form of light which can be amplified by chemiluminescent probes and measured in a luminometer. Activation of cells is achieved using various agents that stimulate the respiratory burst. There is a close correlation between chemiluminescence and other methods of assessing phagocytic function, including bactericidal ability. The technique can be used to assess the function of polymorphonuclear leukocytes, monocytes, and tissue macrophages in response to disease, drugs, and toxins. This article describes the theory of cellular chemiluminescence, and the use of chemiluminescent probes and various cellular stimuli. Practical aspects of cell isolation and factors affecting chemiluminescence are considered. Finally, the clinical applications of chemiluminescence are discussed.

Bronchoalveolar lavage and the immunology of primary lung cancer

Bronchoalveolar lavage (BAL) is a powerful tool with which the immunology of the lung in health and disease can be studied. This technique has been successfully used to characterize localized humoral and cell-mediated responses in sarcoidosis and a number of other interstitial pneumonitides. In contrast, BAL in patients with lung cancer has resulted in some confusion regarding the extent and type of local and systemic immunity in these patients. This review summarizes some of the data obtained from these patients via BAL, but does not attempt to explain the reported discrepancies. The objective of this review is rather to identify gaps which exist in our knowledge of the environmental factors influencing pulmonary immunity in primary lung cancer.

Further studies on the differences in cytotoxicity of human peripheral blood monocytes and bronchoalveolar macrophages for cultured human lung cells

Previously reported differences between the cytostatic activity of human peripheral blood monocytes (PBM) and bronchoalveolar macrophages (BAM) for cultured human lung tumor cells have been further investigated. The differences are both quantitative and qualitative and are shown not to be due to the respective methods of purification. There was a varying contribution of cytolysis to the cytostasis detected by the 75selenomethionine post-labeling assay used. Bronchoalveolar macrophages were cytolytic when tested at both low and high E:T ratios but PBM were only cytolytic at the low E:T ratio. A variable dependence upon soluble cytostatic factor(s) was suggested, and there was evidence of heterogeneity in the factors released by the two populations. Cytostatic factor production by both populations appeared to be under similar regulatory constraints. In vitro maturation of PBM altered their cytostatic dose-response curve to one resembling that previously reported for BAM. It was also shown that sera from poor-prognosis lung tumor patients, which suppressed the in vitro maturation of PBM, also suppressed the in vitro cytostatic activity of PBM for cultured human lung tumor cells.

Phagocytic activity of alveolar macrophages in patients with bronchogenic carcinoma

Human bronchoalveolar cells were obtained by lavage during diagnostic fiberoptic bronchoscopy of 21 patients suspected of having lung malignancies. Of these patients 11 were diagnosed as having primary lung cancer (Group I) and included individuals with squamous cell carcinoma, adenocarcinoma, undifferentiated large and oat cell carcinoma at varying locations and TNM stages, 4 patients demonstrated nonprimary metastatic carcinoma (Group II), and 6 patients did not reveal detectable tumors by bronchoscopy or follow-up (Group III) and were included as study controls. We examined the ability of pulmonary alveolar macrophages (PAMs) lavaged from patients in each of the three study groups to phagocytose opsonized sheep red blood cells. Phagocytic activity varied among patients in the same and different study groups; however, no significant differences were observed in the phagocytic or tumoristatic activities of PAMs recovered from tumor-bearing and nontumor-bearing lung regions of the same patient. Moreover, lavage fluids collected from tumor-bearing regions did not suppress the phagocytic activity of PAMs collected from control lungs nor lung regions contralateral to the tumor-bearing lung. The data do not support the view that bronchial neoplasms or their secreted products suppress phagocytic functions of alveolar macrophages.