Multiple concurrent immunoregulatory defects in cancer patients with depressed PHA-induced lymphocyte DNA synthesis

S. aureus superantigen protein A expands CD4(+)/CD8(+)/CD19(+)/CD34(+) cells in mice: a potential immunorestorer

Protein A (PA) of Staphylococcus aureus is known for its immunostimulatory, anti-cancer, and anti-toxic properties. The present study revealed that PA stimulates specific immunocytes to act as a potential immunorestorer. It has also been shown that the percentage of various cell types bearing different clusters of differentiation markers, e.g., CD4(+), CD8(+), CD19(+), increases considerably after inoculation with PA. It has also been observed that CD34(+) progenitor cells of bone marrow also increased significantly (P < 0.05) upon PA treatment. PA significantly elevated Th-1 cytokines, e.g., IFN-gamma, TNF-alpha, and IL-1alpha. The increased percentages of CD4(+), CD8(+), CD19(+), CD34(+) cells and elevated cytokine levels in PA treated animals may contribute to the reported anti-tumor, anti-fungal, anti-parasitic, and anti-toxic properties of PA. Since in various diseased conditions and during toxic drug therapy lymphocytes bearing such differentiation markers get suppressed, this type of approach could help in immunorestoration of the host. These findings might help in designing therapeutic approaches toward various diseases which cause immunosuppression.

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.

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.

Inhibition of mitogen-activated proliferation of human lymphocytes by hypochlorous acid in vitro: protection and reversal by ascorbate and cysteine

Hypochlorous acid (HOCl) at concentrations of 6.25 microM and greater caused statistically significant, dose-related inhibition of mitogen-activated proliferation of human mononuclear leucocytes (MNL). The anti-proliferative effects of HOCl, which were evident using both undepleted and adherent-cell depleted MNL, could not be attributed to decreased mitogen binding by HOCl-treated cells. The anti-oxidants ascorbate and cysteine (50 microM), when added to MNL prior to exposure to HOCl (25 microM), prevented the anti-proliferative effects of the oxidising agent. Likewise reversal of oxidant-mediated inhibition of the responsiveness of MNL to mitogens was observed when ascorbate and cysteine were added after HOCl treatment of the cells. These results suggest that HOCl, derived from activated phagocytes, is a potential mediator of immunosuppression, especially in the setting of abnormal host anti-oxidant defences.

Plasma glutamate concentration and lymphocyte activity

Elevated glutamate concentrations are commonly observed in tumor patients, and glutamate was recently found to competitively inhibit the membrane transport of cystine. We therefore investigated the possibility that elevated plasma glutamate levels may damage the immune system. The experiments in this report demonstrate a link between the individual plasma glutamate level and the individual immunological reactivity as measured by mitogenic responses. This correlation has been analyzed in 39 colorectal carcinoma patients, 40 oat cell carcinoma patients, 24 large cell lung carcinoma patients, and 31 apparently healthy persons (blood donors). Blood cells from all three groups of tumor patients in comparison with cells from healthy persons produced markedly reduced mitogenic responses against PWM, and all three groups of tumor patients had on average significantly elevated plasma glutamic acid concentrations. Our analysis revealed a linear regression of the logarithm of the individual plasma glutamate levels (before therapeutic treatment) on the logarithm of the corresponding mitogenic reactivity against PWM for the entire population of 134 persons tested (correlation coefficient -0.80; level of significance P less than 0.00001). A statistically significant linear correlation with a similar regression equation was also observed in the group of the healthy blood donors (n = 31; correlation coefficient -0.56; P less than 0.01), indicating that this correlation is universal and not dependent on the presence of a tumor. Mitogenically stimulated murine lymphocyte cultures revealed an inverse correlation between glutamate concentration and cell proliferation in response to the mitogens PHA and PWM.

Elevated plasma glutamate levels in colorectal carcinoma patients and in patients with acquired immunodeficiency syndrome (AIDS)

Amino acid concentrations were analyzed in the sera of HIV (LAV/HTLV-III) positive persons and in the plasma of colorectal carcinoma patients. Both groups of persons showed significantly elevated glutamate concentrations when compared with healthy control persons. Glutamate concentrations were found to be strongly elevated in all groups of HIV-positive persons including patients with acquired immunodeficiency syndrome (AIDS) or lymphadenopathy as well as HIV-positive persons without overt symptoms, indicating that increased plasma glutamate levels may be among the earliest consequences of the HIV infection. Moreover, the increased plasma glutamate concentrations in the colorectal carcinoma patients were correlated with a decreased immunological reactivity (mitogenic responses against concanavalin A). This suggests the possibility that the increased plasma glutamate concentrations may be causally responsible for the decreased immunological reactivity in colorectal carcinoma patients as well as in patients with AIDS.

Surface phenotypes of human peripheral blood mononuclear cells from patients with gastrointestinal carcinoma

Peripheral blood mononuclear cells (PBMC) from 40 patients with gastrointestinal carcinoma (GIC), 13 patients with primary carcinoma in other localizations(non-GIC), and from 57 apparently healthy donors were isolated by Ficoll-Paque gradient centrifugation. The separated cells were stained with several monoclonal antibodies and subjected to analysis on a fluorescence-activated cell sorter. A decreased percentage of PBMC expressing T cell antigens was noted amongst GIC patients, and was mainly due to a reduction of the Leu 2a subset, thus, leading to an increase in the Leu 3a/Leu 2a ratio from 1.4 to 2.1 Non-GIC patients had decreased numbers of both T helper and suppressor cells. Amongst PBMC from GIC and non-GIC patients a statistically increased percentage of cells expressed LeuM 2 (P less than 0.001), LeuM 3 (P less than 0.001), OKM 1 (P less than 0.005), VEP 9 (P less than 0.001), and HLA-DR (P less than 0.001) antigens compared to healthy controls. The percentage of cells bearing these monocyte/macrophage antigens correlated well with the number of cells having monocyte morphology, stained for non-specific esterase, phagocytosed latex particles, and expressed Fc IgG receptor. Our results demonstrate clearly that tumor-bearing patients have an increased relative number of monocytes. The data suggest that cells of the macrophage lineage may be involved in defense mechanisms and changes of the immune system evoked by various tumors.

Modulation of lymphocyte responsiveness to phytohemagglutinin by micromolecular fibrinogen degradation products

The ability of fibrinogen degradation products (FDP) to influence the regulatory function of adherent cells from peripheral blood mononuclear cells (PBMC) was evaluated. FDP were prepared by digestion of fibrin clots with plasmin. These FDP were incubated overnight with glass-adherent cells following which these treated and untreated cells were cocultivated with fresh autologous responder PBMC in the presence of the T-cell mitogen, phytohemagglutinin (PHA). Lipid metabolism of FDP-treated monocytes was evaluated in cells that had been prelabeled with [3H]arachidonic acid (AA) prior to their overnight incubation with FDP; supernatants were analyzed for conversion of AA to cyclooxygenase and lipoxygenase products by thin-layer chromatography. Treatment of glass-adherent cells with the FDP digests converted these monocytes into suppressor cells. The suppression exerted by these cells in the PHA assay was dose dependent. The suppression exerted by FDP-pretreated monocytes was reversed by treating the PHA-stimulated cocultures with indomethacin and was associated with increased cyclooxygenase activity. These studies demonstrated that FDP can alter T-cell immune function through the induction of monocyte suppressor cells; the means by which that occurs is associated with stimulation of lipid metabolism and secretion of eicosanoids with immunoregulatory capacity.

Mitogen-induced gamma interferon production in peripheral blood lymphocytes from patients with colorectal tumors

Mitogen-induced interferon production in peripheral blood lymphocytes from patients with colorectal tumors was not significantly different from that observed in patients with Crohn's disease and sex- and age-matched controls. In the group of patients with colorectal carcinomas, no correlation was obtained with regard to the interferon titer, the in vivo lymphocyte proliferation and the clinical stage of the disease or tumor staging and grading respectively. Most importantly, the data show that despite an obvious defect in T-lymphocyte proliferation, measurement of lymphokine production in mitogen-stimulated cell cultures was not impaired.

Relationship of arachidonic acid metabolism to indomethacin-sensitive immunoregulatory function and lymphocyte PGE sensitivity in peripheral blood mononuclear cells of disseminated solid tumor cancer patients

The relationship between the conversion of arachidonic acid (AA) to E series prostaglandins (PGE), indomethacin-sensitive immunoregulation and lymphocyte PGE sensitivity was investigated in the peripheral blood mononuclear cells (PBMC) of normal subjects and disseminated solid tumor patients. Production of PGE was assessed by thin layer chromatography of ether-extracted glass adherent cells following a 24-hour pulse with 3H-AA. Immunoregulatory cell function was assessed in PHA-stimulated PBMC cultured in the presence of the prostaglandin synthetase inhibitor, indomethacin. Lymphocyte PGE sensitivity was assessed in PHA stimulated glass nonadherent cells cultured in the presence of 10(-8) M PGE. The cells from cancer patients demonstrated greater AA conversion to PGE and greater indomethacin sensitive immunoregulatory cell function than the cells of normal subjects. However, lymphocyte PGE sensitivity was comparable for both groups. When levels of arachidonic acid conversion to PGE were correlated to levels of indomethacin-sensitive immunoregulatory cell function by linear regression analysis, a significant correlation was found. These data suggest that the increased indomethacin-sensitive immunoregulatory cell function seen in PBMC from cancer patients can be directly correlated with increased production of E series prostaglandins by cancer patient peripheral blood monocytes.

Serial immune testing in surgically resected lung cancer patients

Immunoregulation of phytohemagglutinin (PHA) responsiveness by glass-adherent cells and prostaglandin-synthesizing cells was serially monitored in the peripheral blood mononuclear cells (PBMC) of surgically resected stage I and stage II lung cancer patients entered on a trial of adjuvant immunotherapy. The relationship between immunoregulatory cell function, immunocompetence, and disease relapse was determined. Immunoregulatory activity was measured in PHA-stimulated cultures in the presence and absence of 2 micrograms/ml indomethacin and in the presence and absence of glass-adherent cells. In each instance of disease relapse seen, an increase in immunoregulatory cell function to a level significantly different from normal was observed 3 months prior to or coincident with clinical confirmation of disease recurrence. This was usually associated with a decline in PHA responsiveness. In the patients who did not relapse, the levels of PHA responsiveness and immunoregulatory function persisted within normal limits throughout the course of study. Percentages and numbers of leukocytes and leukocyte subsets and delayed cutaneous hypersensitivity were also monitored in this study, but could not be consistently correlated with early changes in clinical disease status. These data suggest that the development of indomethacin-sensitive and glass-adherent suppressor cells may precede and predict for tumor recurrence in surgically resected lung cancer patients.