Prostaglandin-producing suppressor cells in Hodgkin's disease

The effect of indomethacin treatment on lymphocyte PHA reactivity in healthy controls and patients with lymphoma and sarcoidosis

Lymphocytes from healthy volunteers who took indomethacin orally for 3 d showed an enhanced in vitro response to phytohaemagglutinin (PHA). When indomethacin was added in vitro, lymphocytes from healthy controls showed similar but more consistent increases of PHA responses than lymphocytes from patients with sarcoidosis or lymphoma. Moreover, the enhancing effect of indomethacin was by and large more pronounced in those patients who had relatively normal PHA lymphocyte responses in the absence of indomethacin, and the presence of indomethacin failed in most instances to increase subnormal responses to normal control levels. These findings are not consistent with the notion that increased prostaglandin synthesis is the principal cause of subnormal PHA reactivity of lymphocytes from patients with sarcoidosis or lymphoma.

Acute-phase-proteins and parameters of humoral immunity in patients with advanced Hodgkin's disease

Serum concentrations of acute-phase-proteins C-reactive protein (CRP), alpha 1-antitrypsin (AAT), alpha 1-acid glycoprotein (AGP) as well as levels of immunoglobulins G, A and M and of complement components C3 and C4 were evaluated in 15 patients with advanced (stages III and IV) Hodgkin's disease. Of these patients 9 suffered from B symptoms including pruritus, night sweats and fever. While all patients had highly increased concentrations of CRP and AAT and 11 patients also had elevated levels of AGP in their sera, these concentrations were significantly (P less than 0.001) reducible by the administration of chemotherapy. Patients with B symptoms also had significantly higher concentrations of CRP (P less than 0.02), AAT (P less than 0.05) and AGP (P less than 0.05) in their sera than patients without. Plasmapheresis which was performed in 3 patients did not achieve a long-lasting reduction of serum concentrations of any acute-phase-protein tested. Complement components C3 and C4 exhibited a similar behaviour as acute-phase-proteins in that they were elevated in patients with B symptoms and reducible by the administration of chemotherapy (P less than 0.001 and P less than 0.02, respectively). We conclude that serum concentrations of CRP, AAT and AGP can serve as useful markers for the assessment of tumour activity in patients with advanced Hodgkin's disease. Whereas the concentrations of immunoglobulins G and A in patients were comparable to normal controls, IgM was significantly (P less than 0.05) reduced in patients who had received chemotherapy, but not in those who were newly diagnosed and had not received any treatment. Thus, chemotherapy lowered serum concentrations of IgM without influencing levels of IgG and IgA.

Quantitative and functional abnormalities of total T lymphocytes in relatives of patients with Hodgkin's disease

Seven patients, long-term survivors of Hodgkin's disease, and 24 of their relatives (parents, siblings and children), together with normal controls were studied for percentages, absolute counts and mitogen-proliferative responses by means of monoclonal antibodies, E rosette technique and in vitro cultures with PHA, ConA and PWM. The aim of the study was to ascertain whether the impaired cell-mediated immunity of Hodgkin's patients was also present in relatives in order to elucidate the still debated etiology of the defect and of the disease (congenital? environmental? infectious?). The results show that both Hodgkin's patients and their relatives have a significant decrease of total T cells (as T3+, T11+ and E rosette-forming cells) in peripheral blood and a significant impairment of polyclonal responses to all the mitogens employed. The Leu-7+ cells (i.e. a consistent amount of natural killer cells) are significantly increased only in the Hodgkin's patients but not in their relatives. The T cell subpopulations (T4 and T8), B cells and monocytes do not show any difference between the patients, their relatives and normal controls. Our results seem to support, at least in part, the presence of a common defect of T cell lineage both in patients and in their relatives, but its etiology still remains uncertain (genetic? environmental?).

Normalization of monocyte candidacidal deficiency by cyclooxygenase inhibitors in Hodgkin's disease

In a previous work, the authors found that the peripheral blood monocytes from patients with Hodgkin's disease (HD) had depressed lytic capability to kill Candida pseudotropicalis and depressed phagocytic function. The aim of this study was to evaluate if cyclooxygenase inhibitors could correct the defective macrophage functions. Fifteen untreated patients with HD and 10 normal subjects were studied. The incubation of the cells from the patients with HD with indomethacin (IM) at 1, 3, and 10 micrograms/ml and with acetylsalicylic acid (ASA) at 20 micrograms/ml increased their previously deficient ability to kill C. pseudotropicalis, reaching values close to those of normal subjects. The oral administration of ASA during 1 week also corrected the monocyte lytic deficiency in the patients' group. Neither the in vitro nor the in vivo treatment with these cyclooxygenase inhibitors had any significant effect on normal subjects' monocytes' lytic function. The drugs did not improve the impaired phagocytic function in patients with HD. These results indicate that the failure of the lytic activity of the monocytes in HD could be associated to an excessive production of PGE2, and the oral administration of inhibitors of the cyclooxygenase activity can correct such abnormality whereas the phagocytic dysfunction is not reverted by them.

Frequency and anatomic distribution of lymphadenopathic Kaposi's sarcoma in the acquired immunodeficiency syndrome: an autopsy series

Histologic material from 52 autopsies of persons who had died of the acquired immunodeficiency syndrome (AIDS) were reviewed. The study group included 23 Haitians, 19 homosexual men, five intravenous drug abusers, two hemophiliacs (type A), and three persons at unknown risk. Nineteen of the patients (36.5 per cent) had typical Kaposi's sarcoma alone, but 49 (94.2 per cent) had the inflammatory variant of Kaposi's sarcoma as well as typical Kaposi's sarcoma. Inflammatory Kaposi's sarcoma was found in all risk groups studied. In all cases of typical Kaposi's sarcoma, histomorphologic transitions of inflammatory Kaposi's sarcoma to typical Kaposi's sarcoma were observed. Lymph nodes and spleen were the organs most commonly involved by both typical and inflammatory Kaposi's sarcoma. The findings indicate that Kaposi's sarcoma is more common and has a wider morphologic spectrum in AIDS than is generally appreciated.

The effects of indomethacin and interleukin-2 on the proliferation of lymphocytes from patients with lung cancer

The effects of the addition of indomethacin and interleukin-2 (IL-2) to phytohemagglutinin (PHA)-stimulated lymphocytes from patients with untreated squamous-cell carcinoma of the lung and with chronic obstructive pulmonary disease and from normal individuals were studied. In 13 of 21 patients with lung carcinoma, the response of lymphocytes to PHA stimulation was significantly augmented by indomethacin. In these 13 patients, the nonaugmented PHA response was also significantly depressed, with only 1 patient falling in the normal range. In the other 8 patients, the average PHA reactivity was normal, as was the degree of augmentation by indomethacin. In additional studies, IL-2 was added to PHA-stimulated lymphocytes with and without the addition of indomethacin. In the normal group, IL-2 further increased PHA reactivity by an average of 46.0%. The addition of indomethacin to these cultures increased the PHA reactivity by only 8.8%, which is similar to the indomethacin effect for the PHA-stimulated cells without the addition of IL-2. In the cancer group, the PHA reactivity of 13 of 19 patients was significantly increased by the addition of IL-2. When indomethacin was added simultaneously with IL-2, the proliferative response for 12 of 19 patients was increased significantly more than for the normal controls. Thus, this study indicates that the PHA reactivity of lymphocytes from many lung carcinoma patients is augmented to a greater extent than for normal individuals by inhibiting prostaglandin synthesis. Also, the addition of IL-2 to these PHA-stimulated cultures did not mimic the addition of indomethacin, but instead the effects were usually additive.(ABSTRACT TRUNCATED AT 250 WORDS)

[Eicosanoids and phospholipases]

Prostaglandins, thromboxanes, and leukotrienes have been implicated to play an important role in physiology as well as in a growing list of pathophysiologic conditions. These oxidation products of 8.11.14-eicosatrienoic-, 5.8.11.14.-eicosatetraenoic-, and 5.8.11.14.17.-pentaenoic acids have been collectively designated eicosanoids. Many clinically important diseases are associated with altered eicosanoid biosynthesis. Furthermore, a series of hormones are known to induce acutely formation of eicosanoids, suggesting a crucial role in a multitude of tissue responses including phenomena such as secretion, platelet aggregation, chemotaxis, and smooth muscle contraction. The major precursor for the eicosanoids seems to be 5.8.11.14.-eicosatetraenoic acid or arachidonic acid. Virtually all of arachidonic acid however is present in esterified form in complex glycerolipids. Since cyclooxygenase and the lipoxygenases utilize arachidonic acid in its free form, a set of acylhydrolases is required to liberate arachidonic acid from membrane lipids before eicosanoid formation can occur. It became only recently apparent that a minor acidic phospholipid, phosphatidylinositol, comprising only 5%-10% of the phospholipid mass in mammalian cells, plays an important role in arachidonic acid metabolism. Phosphatidylinositol--after phosphorylation to phosphatidylinositolphosphate and phosphatidylinositolbisphosphate--appears to be hydrolyzed by specific phospholipases C generating 1-stearoyl-2-arachidonoyl-diglyceride. Diglyceride serves as substrate for diglyceride lipase to form monoglyceride and free fatty acid. Alternatively diglyceride is phosphorylated by diglyceride kinase yielding phosphatidic acid, which is believed to be reincorporated into phosphatidylinositol. In addition to phosphatidylinositol phosphatidylcholine, phosphatidylethanolamine and phosphatidic acid may contribute to arachidonic acid release. These phospholipids are substrates for phospholipases A2 generating free arachidonic acid and the respective lysophospholipid. Understanding of the biochemistry of arachidonic acid liberation may be critical in developing strategies of pharmacological intervention in a variety of pathological conditions.

Impaired interleukin regulation of the phytohemagglutinin response in Hodgkin's disease

Patients with active Hodgkin's disease (HD) often demonstrate an impaired T-cell proliferative response to phytohemagglutinin (PHA). The present study examined if interleukin regulation of the PHA response was defective in HD. The Hodgkin's PHA response was impaired at all concentrations of PHA utilized. Indomethacin increased the proliferative response but did not bring it to control levels. Stimulation of the cells with both PHA and irradiated Ia+ B cells normalized proliferation despite identical PGE2 concentrations as in the PHA alone cultures. Hodgkin's monocytes produced normal amounts of interleukin 1 (IL-1). Interleukin 2 (IL-2) production by Hodgkin's T cells was decreased in the PHA stimulated cultures, but was normal in the PHA and Ia+ cell stimulated cultures. In response to PHA stimulation alone, Hodgkin's T cells expressed less IL-2 receptor than control cells. The data suggest the diminished PHA response in HD is due to impaired IL-2 production resulting in diminished IL-2 receptor expression. However, when an Ia+ cell source is added to PHA as an additional stimulator, both TCGF production and proliferation are normalized. Monocytes serve to modulate the magnitude of the PHA response through production of both interleukin 1 and PGE2. However, in the presence of sufficient IL-2 production the influence of monocytes is minimized.

Modulation of suppressor-cell activity by cimetidine in patients with common variable hypogammaglobulinemia

Because of evidence of a possible immunoregulatory role for cimetidine, an antagonist to histamine H2 receptors, we studied the effects of this drug in five adult patients with common variable hypogammaglobulinemia. Three patients had excessive suppressor-cell function associated with panhypogammaglobulinemia, whereas the other two had no apparent T-cell defects. The patients were given a one-month course of oral cimetidine (1200 mg daily in four divided doses). Subsequently, the three patients with excessive suppressor-cell function had a marked reduction in suppressor activity along with a decrease in the number of suppressor cells (T8+). One of these three had a marked rise in both in vitro immunoglobulin secretion and serum immunoglobulin concentrations, which was reversible after the drug was stopped for three months and reproducible when therapy with cimetidine was repeated. There was no difference in immunoglobulin secretion or suppressor-cell activity while taking cimetidine between the two patients with common variable hypogammaglobulinemia without excessive suppressor-cell activity and control patients with duodenal ulcers. The data suggest that H2-receptor antagonists may decrease excessive suppressor-cell activity and allow endogenous immunoglobulin production in some patients with common variable hypogammaglobulinemia.

Immunosuppressor control as a modality of cancer treatment: effect of plasma adsorption with Staphylococcus aureus protein A

In tumor-bearing hosts both cellular and humoral tumor-growth-enhancing factors are present. They cause immunosuppression and facilitate the growth of tumors. Very early during tumor growth these factors are either elicited by the tumor cells or induced by the host immunocytes. Among these immunosuppressive agents, circulating immune complexes appear to play a predominant role. They also activate suppressor cell activity. Plasma adsorption of CIC and IgG by protein A of Staphylococcus aureus has been reported to cause tumor regression. Plasma adsorption with protein A-collodion charcoal, protein A-silica, or protein A-Sepharose also induced tumorilytic reactions. Even direct infusion of protein A induced tumor regressions in rat mammary tumors. Recent studies showing tumor regressions following S. aureus Wood 46 plasma adsorption or infusion of normal plasma adsorbed over S. aureus indicate that specific blocking factor removal by plasma adsorption may not be the mechanism for causing tumor destruction. Results indicate that S. aureus plasma adsorption leaches a number of staphylococcal agents. Thus, it appears that staphylococcal agents, protein A, enterotoxin, and other factors are responsible for the induction of reactions leading to tumor destruction. A unified mechanism explaining the results obtained with plasma adsorption using protein A of S. aureus, or S. aureus Wood, or direct protein A infusion, was presented.

Anti-Ia reactivity in sera of untreated patients with active Hodgkin's disease

The effect of sera from eight patients with Hodgkin's disease on the autologous and allogeneic mixed lymphocyte response of normal individuals was examined. Sera from three patients with active disease caused marked inhibition of both autologous and allogeneic mixed lymphocyte reaction without inducing significant reduction of the phytohemagglutinin-induced proliferative response. The inhibitory activity of Hodgkin's disease sera on the autologous mixed lymphocyte reaction was removed by adsorption with non-T, but not T, lymphocytes and it was correlated with the ability of such sera to block the binding of monoclonal anti-Ia antibody to Ia-positive target cells. Anti-Ia antibodies were detected in the same sera by double antibody radioimmunoassay and analysis on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, using 125I-labeled, partially purified, Ia antigens from two different human B-cell lines. This anti-Ia reactivity was strongly reduced or absent in sera taken from the same patients at the completion of multidrug chemotherapy.

Inhibition of interleukin 2 production by prostaglandin E2 is not absolute but depends on the strength of the stimulating signal

In view of the eminently important role of interleukin-2 (IL-2) in T-cell responses, and in view of reports about immune stimulatory effects of PGE2, we reinvestigated the question whether PGE2 inhibits IL-2 production. It was found that PGE2 does not inhibit IL-2 production in murine spleen cell cultures after optimal stimulation (5 micrograms/ml concanavalin A) but does inhibit at suboptimal stimulation conditions. The failure of PGE2 to inhibit IL-2 production at optimal concanavalin A concentration was demonstrated by two independent IL-2 assays namely by the co-stimulator assay and by the proliferation of IL-2-dependent T-cell clone W-2. Our observations indicated that the inhibitory effect of PGE2 depends on the strength of the stimulating signal. IL-2 production in cultures with 5 micrograms/ml concanavalin A was also not suppressed by PGE1, by prostaglandin D2, thromboxane B2 (T X B2), and prostaglandin F2.

Augmentation of mitogen-induced proliferative responses by in vitro indomethacin in patients with acquired immune deficiency syndrome and AIDS-related complex

The effect of indomethacin on mitogen-induced lymphocyte proliferative responses was studied in six normal heterosexual subjects and nine patients with the acquired immune deficiency syndrome (AIDS) and AIDS-related complex (ARC). Indomethacin enhanced only Con A-induced lymphocyte responses in six heterosexual men. In contrast, study of the cells from AIDS and ARC revealed that indomethacin enhanced PHA-induced lymphocyte proliferative responses from 52,600 counts/min to 70,900 counts/min (P less than 0.005) and 81,400 counts/min (P less than 0.001) at 0.1 and 1 microgram/ml. respectively and increased Con A-induced lymphoproliferation from 30,800 counts/min to 52,000 counts/min (P less than 0.01) at 0.1 microgram/mg and 51,1000 counts/min (P less than 0.005) at 1 microgram/ml. These results suggest that indomethacin enhanced mitogen-induced lymphoproliferative responses in vitro with cells from patients with AIDS and AIDS-related complex and may have therapeutic potential in some patients with AIDS.

Hodgkin's disease: five steps from autoimmunity to cancer

A five-step hypothesis on the pathogenesis of Hodgkin's disease (HD) is presented. Weak immune suppressor activity gives a predisposition for the development of the disease, after which a non-specific immune stimulation can initiate a self-perpetuating uncontrolled stimulation between interdigitating cells (IDCs), macrophages and helper T lymphocytes (TH). The disease spreads to other lymph nodes through the secretion of humoral factors and by migration of cells. The response of the suppressor branch of the immune system is delayed, and comes from areas not yet involved in the disease, primarily from the spleen and bone marrow. Treatment will result in the predominance of the suppressor activity and allow calming of the disease. In a terminal phase, a possible neoplastic transformation of the chronically stimulated immune cells may give rise to frequent extranodal localizations and a rapid progression of the disease.

Rationale for a novel immunotherapy of cancer with allogeneic lymphocyte infusion

A simple method of cancer immunotherapy has been developed which achieves marked objective response in 20-30% of patients with disseminated disease. Each course consists of a low dose of chemotherapy followed two days later by intravenous infusion of allogeneic lymphocytes. Courses are repeated on a monthly basis as needed. The function of the chemotherapy--too mild to significantly influence tumor growth directly--appears to be depletion of suppressor T cells, which sensitizes the patient to the immunostimulant action ("allogeneic effect") of the subsequently infused lymphocytes. The rationale for this method is discussed in the context of a review of past attempts at lymphocyte immunotherapy. We are now attempting to improve response rates by combatting anergy with nutritional immunopotentiators, and by preventing prostaglandin-mediated or -dependent immunosuppression with prostaglandin synthetase inhibition. By understanding and counteracting the various specific and general means by which a growing tumor induces host tolerance, it should prove possible to achieve immune-mediated tumor regression in a high proportion of patients. Best results may be seen when allogeneic lymphocyte therapy is initiated at an earlier stage of the disease, and is used in conjunction with surgery, radiotherapy, short-course intensive chemotherapy, or hyperthermia-based methods.

Amplification by macrophages of prostaglandin-mediated immunosuppression in mice bearing syngeneic tumors

The role of macrophages in tumor-mediated immunosuppression was examined, using C57B1/6 strain mice bearing four different immunosuppressive transplantable syngeneic tumors (Lewis Lung Carcinoma, B16 Melanoma, and two fibrosarcomas induced by methylcholanthrene in our laboratory). When tested for immunosuppressive activity, in inhibiting the induction of antibody formation by normal spleen cells in response to SRBC in vitro, the splenic and peritoneal macrophages from tumor-bearing mice were all significantly suppressive. The degree of suppression correlated with immunosuppression in tumor-bearing mice challenged in vivo with SRBC. Direct action of tumor cells on normal splenic macrophages in vitro caused them to become suppressive, the extent of suppression dependent on the time of interaction and on the immunosuppressive activity of the tumor cells in vivo. Pretreatment of suppressive splenic macrophages with indomethacin, a potent inhibitor of the synthesis of prostaglandins (PG), reduced significantly their immunosuppressive activity. Also, peritoneal macrophages from tumor-bearing mice produced significantly more PGE in culture than control macrophages. Thus, tumor-activated macrophages, presumably those macrophages that infiltrate the tumor in a host reaction against the tumor, serve to amplify the level of immunosuppression in the host by producing relatively large amounts of PGE that is a key physiological mediator in the activation and function of suppressor T lymphocytes. The stimulation of PGE synthesis in macrophages, as a result of their interaction with syngeneic tumors, is initiated by PGE produced in relatively large amount by the tumor cells.

Trypanosoma gambiense: immunosuppression and polyclonal B-cell activation in mice

The relationship between the suppression of antibody response and polyclonal B-cell activation was studied in mice treated with a cell homogenate of Trypanosoma gambiense. The cell homogenate injection in mice caused a progressive increase in splenic background plaque-forming cell response to sheep erythrocyte. In the mice with markedly increased background plaque-forming cell response, the different reactivity in the primary antibody response to sheep erythrocytes was observed between the intraperitoneal and intravenous immunization with sheep erythrocytes. The intraperitoneal immunization of mice with sheep erythrocytes strongly suppressed the antibody response, while the intravenous immunization with sheep erythrocytes led to an enhancement of the antibody response. The intraperitoneal injection of silica particles, a toxic agent to macrophages, 30 min before intraperitoneal immunization with sheep erythrocytes abolished the suppression of the antibody response completely. In addition, restoration of the suppressed antibody response was found in mice immunized intraperitoneally with a high dose of sheep erythrocytes. It appears that the suppression of antibody response is not attributable to polyclonal B-cell activation, and is associated with the elevation of the phagocytic activity of peritoneal macrophages.

In vitro antigen-induced antibody responses to hepatitis B surface antigen in man. Kinetic and cellular requirements

In this report we define the parameters of the human immune response after immunization with hepatitis B vaccine. 2 wk after booster immunization, there is significant spontaneous secretion of antibody to hepatitis B surface antigen (anti-HBs IgG), which is not further augmented by stimulation with antigen or pokeweed mitogen (PWM). By 4 wk there is little spontaneous secretion of specific antibody, and low doses of antigen or PWM produce significant increases in the amount of anti-HBs IgG produced. By 8 wk the peripheral blood mononuclear cells are refractory to stimulation by antigen, but anti-HBs IgG is produced in response to PWM. 0.5 yr or more after the last immunization, some individuals will manifest an antigen-induced specific antibody response. This induction of anti-HBs IgG by hepatitis B surface antigen (HBsAg) is monocyte- and T cell-dependent. Note that there is a dichotomy in the T cell response to HBsAg. The specific antibody response is clearly T cell dependent, but no in vitro T cell proliferative response to HBsAG could be demonstrated in the immunized individuals. Although the precise reason for the absent proliferative response to HBsAg despite well-established humoral immunity has not been determined, there was no evidence to suggest nonspecific suppression by HBsAg or the presence of an adherent suppressor cell population. The ability to evaluate antigen-induced, antigen-specific responses to HBsAg will be useful in defining the unique interaction between the human immune response and this clinically important viral agent.

Effects of prostaglandin E2 on responses of T-cell subsets to mitogen and autologous non-T-cell stimulation

The cellular basis for prostaglandin E2 (PGE2)-mediated suppression of human T-cell proliferative responses was examined. Proliferation in response to concanavalin A was found to be more sensitive to the suppressive influence of PGE2 than was that to phytohemagglutinin. Studies of separated T cells indicated that T4+ cells were inhibited to a greater extent than were T8+ cells. Addition of interleukin 2 (IL-2) to the cultures did not overcome the suppression. In studies conducted in the autologous mixed-lymphocyte reaction (AMLR), both the T4+ cells and the T8+ cells were inhibited by PGE2, however, the T8+ cells were much more prominently inhibited. The inhibitory effect of PGE2 on the responsiveness of T8+ cells was found to be due to inhibition of T4+-dependent IL-2 production. In contrast to the case of mitogen-induced proliferation, the suppression of the AMLR by PGE2 was overcome by addition of IL-2. These results help explain the previously reported suppression of the (B + null) cell induced AMLR by macrophages (which produce PGE). Moreover, they indicate that the effects of the macrophage product, PGE2, can be differentially observed in functional activities of T-cell subsets.

Indomethacin enhances the proliferation of mitogen-stimulated T lymphocytes of homosexual males with persistent generalized lymphadenopathy

The possibility that cyclooxygenase products of arachidonic acid might contribute to the defective T lymphocyte function of homosexual men with the reactive lymph node syndrome was examined in vitro. T lymphocyte proliferation, assessed by the uptake of [3H]thymidine after the addition of phytohemagglutin, was 72,870 +/- 66,816 counts per minute (mean +/- SD) for eight patients and 119,589 +/- 64,913 counts per minute for 30 controls (P less than 0.05, Student's t test). Treatment with the cyclooxygenase inhibitor indomethacin increased the phytohemagglutin-induced proliferation of the T lymphocytes from five of eight patients, but none of 12 healthy homosexual and heterosexual control subjects. The production of prostaglandin E2 by T lymphocytes from six patients was 16.1 +/- 10.5 pg/5 X 10(6) cells/hr, as contrasted with that of 4.9 +/- 1.3 and 4.3 +/- 2.1 pg/5 X 10(6) cells for four healthy homosexual and six healthy heterosexual control subjects, respectively (P less than 0.01, Student's t test). The production of prostaglandin E2 by the patients' monocytes was normal. Abnormalities of the cyclooxygenase pathway of T lymphocytes of patients with the reactive lymph node syndrome may reflect an immunoregulatory defect, which predisposes to infections and may evolve into the more severe abnormalities of the acquired immune deficiency syndrome.

Soluble suppressor factors elaborated in experimental malignant ascites

Soluble suppressor factors in the sera of cancer patients inhibit lectin-stimulated lymphocyte proliferation. These factors, derived from human material, preclude easy corroboration by other investigators. To gain a general understanding of soluble suppressor factors and to avoid the necessary restrictions of human experimentation, an animal model was devised. Sprague-Dawley rats were injected ip with the Walker 256 carcinoma. The resultant ascites proved to be a stable, reproducible source of soluble suppressor factors. Ascites inhibited phytohemagglutinin (PHA)-induced blastogenesis of normal splenocytes by 98%. The possibility of a toxic effect was eliminated by vital staining of splenocytes and by examination in a specific lymphotoxin assay. Suppressor activity persisted after heating at 100 degrees C for 40 min. Extraction by lipid solvents revealed that the bulk of suppressor activity resides in the lipid phase. The active fraction of heat-treated ascites passed through an Amicon PM-10 filter. Thin-layer chromatography revealed the presence of prostaglandins E2 and F2 alpha. Tissue culture supernatants from short-term cultures derived from tumor-bearing animals revealed suppressor activity from thymus, spleen, and liver cultures (97, 91, and 71%, respectively). No suppressor activity was detected in cultures of cancer cells. This study has demonstrated in this animal model that prostaglandins play a major role in suppression of lectin-induced blastogenesis. All suppressor factors appear to be host derived. An understanding of the mechanism of release of these suppressor substances may open new avenues in the immunotherapy of cancer.

Characterization of multiple immune defects in human malignant lymphoma

Sixty-three patients with Hodgkin's disease (HD) or non-Hodgkin's lymphoma (NHL) were studied to analyze the mechanisms responsible for impaired in vitro lymphocyte reactivities to the mitogen concanavalin A. Lymphocytes from 43 of the 52 untreated patients acquired enhanced in vitro responsiveness after preculturing in media alone for 3 days. However, 38 of the untreated patients failed to achieve entirely normal lymphocyte responses after preculturing . Suppressor cells were detected in 25 patients, but the intensity of suppression was much less than expected when compared with the severity of in vitro impairments. Suppressor activity did correlate with certain clinical characteristics in NHL, whereas no correlation was observed for HD. In contrast to the untreated patients, successfully treated patients demonstrated either normal responses or profound, irreversible impairments. The data indicate that several mechanisms which usually coexist can contribute to the impaired in vitro lymphocyte responses in untreated HD and NHL, and that a single, irreversible type of mechanism explains the impaired reactivities in successfully treated patients.

Specific suppressor T cell function in a patient with Graves' disease and her healthy identical twin

Immunoregulatory defects have been suggested in autoimmune disorders including Graves' disease. The finding that Concanavalin A-induced suppressor T cell function was sub-optimal in Graves' disease has been disputed; a restricted defect in TSH-receptor antigen-specific suppressor cells has instead been proposed by Okita et al. (1980). To explore this further, we studied both specific and non-specific suppressor cell function in a pair of HLA identical twins, one of whom had Graves' disease. By contrast to the euthyroid healthy twin and 10 healthy controls (612 cpm/10(6) cells) the patient's mononuclear cells (MNCs) incorporated more (3H)-thymidine (7365 cpm/10(6) cells) in response to thyroid membrane antigen (TMA). Removal of glass-adherent cells before addition of antigen increased (3H)-uptake by cells from the healthy twin to 1808 cpm but reduced those from the Graves' twin to 3411 cpm. The influence of MNCs cultured with Con A or TMA for 24 h upon (3H)-thymidine uptake by 2 X 10(6) indicator cells triggered by Con A for 72 h or TMA for 96 h was taken as a measure of non-specific and specific suppressor cell function respectively. Both Con A and TMA induced suppressor cells were reduced, the latter to a more marked degree, in the patient compared to the healthy twin; mixing of MNCs from patient and healthy twin in a 1:1 ratio improved the patient suppressor cell function. When the patient's MNCs triggered for 24 h with Con A were mixed in a 1:1 ratio with her fresh MNCs and TMA, less blast transformation was found compared to an equal number of fresh cells (3H-thymidine uptake 3250 vs 7365 cpm/10(6). Similarly, preincubated cells from the healthy twin had greater suppressive effect (1820 cpm/10(6) cells). We conclude that (1) the HLA identical healthy twin has TMA autoreactive lymphocytes regulated by adherent regulatory cells; (2) the increased ratio of helper/suppressor cells in the adherent cell population in the patient leads to a decrease of (3H) incorporation upon their removal; (3) in the patient, the specific suppressor cell defect is more severe than the non-specific defect; (4) lack of specific TMA induced triggering may be the critical immunoregulatory defect in Graves' disease.

Increased sensitivity to indomethacin of mice bearing the BCL1-leukemia

Indomethacin is a non-steroidal anti-inflammatory agent that inhibits prostaglandin synthesis. Administration of indomethacin, in doses which were non-toxic to normal BALB/c mice, to mice bearing the BCL1 leukemia resulted in increased mortality of these animals. This effect was only observed if the indomethacin was administered to animals with advanced disease (splenomegaly, hepatomegaly and leukemia). If indomethacin treatment was initiated prior to transplantation of the tumor or 2 weeks post-transplantation, and continued throughout the disease process, there was no effect on either the course of the disease or mortality. Injection of similar doses of indomethacin into mice bearing advanced B16 melanoma tumors did not result in increased mortality. Therefore, metabolic changes which occur in the leukemic animals may uniquely alter host sensitivity to this non-steroidal anti-inflammatory agent. The BCL1 leukemia may be a useful animal model to provide insights into the biochemical basis for the adverse reactions experienced by some Hodgkin's disease patients when they are treated with anti-inflammatory agents such as indomethacin.

Macrophages in murine uterus are immunosuppressive

The mechanisms by which the fetal allograft is protected from a maternal anti-fetal immune response are not understood. This study was designed to examine the possibility that tissues near the developing fetus contain immunoregulatory cells and to begin the process of identification of those cells. Dispersed uterine cell suspensions from pregnant Swiss/Webster mice consistently inhibited the responses of normal murine spleen cells to the polyclonal mitogen phytohemagglutinin (PHA). These suspensions contained few lymphocytes (mean 1%), but abundant macrophages (mean 28%), identified by morphology and Fc gamma-receptor expression. Depletion of Fc gamma-receptor-positive cells restored spleen cell (SC) responses to PHA to near normal levels and partial depletion of adherent cells provided varying degrees of relief of the observed suppression. Adherent cells (greater than 95% macrophages) recovered from plastic surfaces were highly immunosuppressive. Suppressor cells appeared to interfere with both early and late stages of spleen cell proliferative responses. The results suggest that cells with some characteristics of macrophages within tissues near the maternal-fetal interface may create a local environment prohibitive to maternal lymphocyte proliferation.

Management of the immunocompromised host

This article deals with the management of the immunocompromised host. Mechanisms of immunocompromise include alterations in skin and mucosal barriers, normal oral and intestinal flora, splenic function, and number or function of T cells, B cells, granulocytes, and monocytes. Discussed in this article are ways for maintaining those defenses not altered by the primary disease, minimizing the environmental risks to the patient, anticipating potential infections in order to institute appropriate prophylactic measures, and diagnosing and aggressively treating infections as they occur.

Decreased T lymphocyte migration in patients with malignancy mediated by a suppressor cell population

The migration and concentration of lymphocytes at sites of antigenic challenge are an integral part of the expression of delayed cutaneous hypersensitivity, as well as of tumor and graft rejection. In this study, we have analyzed the migration of T lymphocytes from patients with malignancy. We used casein and concanavalin A (Con A)-stimulated mononuclear cell supernatants to stimulate T cell locomotion. Peripheral blood T lymphocytes from 30 patients with established malignancy, 10 patients with indolent malignancy or benign tumor, and 42 normal adult controls were tested. Data are expressed as a migration index (MI), which represents the difference in micrometers between the distance migrated in response to a stimulus and the distance migrated in response to media alone. We observed a marked depression in casein-stimulated T lymphocyte migration in patients with established malignancy (mean MI +/- 1 SD = 17.0 +/- 9 microns) as compared with normal adult controls (mean MI +/- 1 SD = 35.3 +/- 10 microns). Similar results were observed with migration in response to Con A supernatants. T cells from patients with established malignancy had a mean MI of 5.8 +/- 4 microns to Con A supernatants as compared with 24.5 +/- 5 for controls. This depressed migration was apparent both in the distance that cells migrated and in the number of cells that migrated into the membrane. Of 10 patients with indolent malignancy or benign tumor, T cell migration in 8 was not significantly decreased as compared with controls. When we mixed equal concentrations of normal control T lymphocytes with T lymphocytes from patients with cancer and added the mixture directly to the upper compartment of the chemotaxis chamber, the response of the normal T cells to casein was inhibited by an average of 48%. We observed inhibition of this migration of normal cells when we added as little as 10% of patient cells to normal cells. When we mixed normal control T lymphocytes from different donors and added them directly to the upper compartment of the chemotaxis chamber, T lymphocyte migration in response to casein was not significantly altered. If T cells from patients with cancer were cultured overnight, the suppressive effect on lymphocyte locomotion was lost. Our results indicate that there is a population of T lymphocytes in patients with cancer that suppress normal T lymphocyte migration. This suppressor activity may partially explain the subversion of immunosurveillance in established neoplastic states, as well as the defective inflammatory reaction to intradermal injection of antigen observed in many patients with malignancy.

An improved method for assessing the incorporation of labeled precursors into DNA by human mononuclear cells

The blastogenic responsiveness of activated lymphoid cells is usually assessed in vitro by measuring the incorporation of radioactive thymidine or iododeoxyuridine, a thymidine analog, into DNA. The accuracy of this method is compromised by the presence in activated and unactivated lymphocytes and in some of the substances used to activate them, of degradative enzymes which compete with DNA synthetase, the incorporation efficiency of exogenous precursor is inherently low. We have done studies aimed at improving both the efficiency and the accuracy of the assay system by selectively inhibiting the enzymes responsible for thymidylate synthesis de novo and DNA precursor degradation. Culture conditions were investigated and potential inhibitors were tested using human peripheral blood mononuclear cells activated with phytohemagglutinin. Nucleoside-degrading activity of mammalian and bacterial cells is due largely to nucleoside phosphorylases, enzymes that require orthophosphate for activity. We partly inhibited DNA precursor degradation by lowering the phosphate concentration in the culture medium and lowering the pH, thereby reducing the orthophosphate concentration. To reduce precursor degradation further, we tested several potential nucleoside phosphorylase and thymidylate synthetase inhibitors at various concentrations. Our data show that the addition of 1 mM fluorouracil and 1 mM deoxyuridine to the culture medium largely prevents degradation of radioactive thymidine and iododeoxyuridine without unduly compromising the DNA-labeling efficiency of cells activated with mitogens or bacterial homogenates. Under these conditions, label incorporation increases linearly as the number of blast cells or the labeling time increases.

Spontaneous and Concanavalin A-induced suppressor activity in control and Hodgkin's disease patients

Indirect evidence suggests that abnormal regulation of B cells exists in Hodgkin's disease (HD) due, perhaps, to the sequestration of regulatory T-lymphocyte subpopulations in the spleen in this condition. Other work implicates the B-cell itself in this abnormality. In this study we have attempted to measure regulatory T-cell function by quantitating spontaneous and Concanavalin A(Con A)-induced suppressor activity in T-enriched spleen cells from control and HD spleens for pokeweed mitogen(PWM)-induced immunoglobulin (Ig) production. Using this polyclonal system, HD patients' spleen T-lymphocytes could not be shown to differ markedly from the control series. Cells capable of spontaneous and mitogen-induced modulation of Ig synthesis were present in both populations and showed a reciprocal relationship implying the activation of the same cell type. In this respect HD and control spleen resembled peripheral blood. A limited parallel investigation of PWM-regulatory activity in cells from spleen and peripheral blood from individual patients was also undertaken. Individual patients showed wide variation in suppression between the two compartments and, therefore, measurements of functional capacity in blood alone may not provide a true estimate of total regulatory capacity in lymphoma patients.

Modulation of immunologic responses in nontuberculous mycobacterial infections with indomethacin

We have previously reported that impaired in vitro cellular immunity is a common finding in patients with nontuberculous mycobacterioses and that the subnormal responses may be improved by indomethacin. Subsequently, we have studied the in vivo effects of indomethacin on cell-mediated immune functions of four patients with Mycobacterium avium-intracellulare infections. Prior to treatment none of the patients had delayed cutaneous reactions to purified protein derivative (PPD) of the tubercle bacillus, and their lymphocytes had subnormal in vitro proliferation responses to tuberculins from M. tuberculosis and M. avium-intracellulare and to phytohemagglutinin. The administration of indomethacin reconstituted both the in vitro lymphocyte responses and delayed cutaneous hypersensitivity. We propose that the impairment of T-cell dependent immune functions is mediated by a suppressive factor (or factors) that is a metabolic product(s) of the cyclooxygenase pathway of arachidonic acid metabolism. Preferential inhibition of this pathway with indomethacin allows the expression of cell-mediated responses.

Macrophage-derived prostaglandin E modulation of the mixed-lymphocyte reaction: an anomaly of increased production and decreased T-cell susceptibility during tumor growth

One-way mixed-lymphocyte reactions (MLR) were used to assess macrophage (M phi)-derived factor-mediated modulation of normal and tumor-bearing host (TBH) T-cell immune responsiveness. Normal and TBH M psi culture supernatants contained the inhibitory substance prostaglandin E (PGE) in concentrations of 10(-8) to 10(-9) M, with TBH M phi supernatant containing approximately twice the amount of PGE as its normal counterpart. Normal and TBH MLR reactivity were both suppressed by the addition of normal host M phi supernatant. However, TBH T cells were less inhibited by TBH M phi supernatant (55%) as compared to normal host T cells (73%). Although dialyzed M phi supernatants were less inhibitory (17-19%) on normal host T-cell MLR reactivity, TBH T-cell responses were enhanced (20-46%). Indomethacin or eicosatetraynoic acid treatment of M phi reduced PGE levels in the supernatants and in general enhanced MLR reactivity. When PGE1 and PGE2 were titrated in the MLR, normal host T lymphocytes were more susceptible to inhibition than were TBH. Concentrations of PGE1 and PGE2 comparable to that found in normal host M phi supernatants caused approximately 38% inhibition whereas whole M phi supernatants decreased MLR reactivity by greater than 70%, suggesting that another factor(s) was necessary to account for the additional M phi-mediated suppression of lymphocyte function. Isoelectric focusing was used to fractionate normal host M phi supernatant. Two factors with isoelectric points in the pH ranges 7.0-8.5 and 4.5-5.0 were inhibitory in the MLR. An enhancing factor was also identified with an pI in the range of pH 6.0-7.0. These data suggest that TBH M phi-derived PGE production was increased over its normal counterpart, but that TBH T cells were less susceptible to its effect and an additional factor(s) was working in concert with PGE.

Monoclonal antibody-defined T-cell phenotypes and phytohemagglutinin reactivity of E-rosette-forming circulating lymphocytes from untreated chronic myelocytic leukemia patients

T-cell phenotypes, as defined by murine monoclonal antibodies, (OKT3, OKT4, OKT8, OKIa1), and phytohemagglutinin (PHA) reactivity, were evaluated in E-rosette forming cells (T-cells) from 10 untreated chronic myelocytic leukemia patients. The proportion of T4+ cells was lower in patients than in controls (41.6 versus 61.7%, P less than 0.02); whereas the proportion of T8+ cells was similar in patients and controls. The decrease in T4+ cells in CML resulted in a decrease in circulating T4+/T8+ ratio (P less than 0.02). The Ia1+ T-cells were increased in most CML (8 of 9) patients, while control subjects never displayed Ia1+ T-lymphocytes (P less than 0.01). The PHA reactivity of E-rosette forming lymphocytes was significantly impaired in CML patients with respect to controls (P less than 0.02). The presence of Ia antigen on T-cells was positively correlated with the T8+ cell phenotype (P less than 0.001) and inversely correlated with the T4+ (helper) cell phenotype (P less than 0.05). Furthermore, there was a trend towards an inverse correlation between the PHA response and the level of Ia1+ or T8+ cells, there is no correlation between PHA reactivity and T4+ phenotype. The results suggest that the T-lymphocyte population from untreated CML patients is intrinsically abnormal.

Immune dysfunction in diabetes-prone BB rats. Interleukin 2 production and other mitogen-induced responses are suppressed by activated macrophages

Spleen cells of diabetes-prone BB Wistar rats were found to generate excessively low proliferative responses, and interleukin 2 (IL-2) levels in response to T-dependent mitogens. This abnormality was not due solely to abnormal T cell numbers since: (a) addition of BB spleen cells of BB splenic macrophages to normal major histocompatibility complex (MHC)-matched Wistar Furth (WF) spleen cells resulted in severe suppression of concanavalin A (Con A)-, phytohemagglutinin (PHA)-, and pokeweed mitogen (PWM)-mediated proliferation, and IL-2 production; (b) macrophage depletion from BB spleen cells, but not B cell or T cell depletion, removed completely the suppressive effects of BB cells on WF cells; (c) macrophage depletion greatly enhanced the response of BB lymphocytes to T-dependent mitogens. Although suppressor macrophages could also be found in the spleen of WF control rats they were present in much smaller numbers than in the spleen of BB rats. The suppressive effect of BB macrophages was partially reduced by addition of the prostaglandin synthetase inhibitor indomethacin to cultures. Furthermore, indomethacin (but not catalase or PMA) considerably augmented IL-2 secretion of Con A-stimulated BB spleen cells, but had little effect on WF spleen cells. In contrast, prostaglandins E1 and E2 (PGE1 and PGE2) suppressed IL-2 production. While IL-2 secretion was severely depressed in BB rats unstimulated and lipopolysaccharide (LPS)-stimulated IL-1 secretion by splenic macrophages was normal. BB macrophages did not inactivate IL-2. Low IL-2 production and macrophage-mediated suppression were features of all BB rats tested.

Macrophage depletion and manipulation of enhanced immune response in an animal model of bladder cancer

In a transplantable model of bladder cancer the inhibition of tumor growth by polyinosinic:polycytidylic acid (poly(I:C], concomitant stimulation of natural killer cell activity, and inhibition of both effects by prior inoculation with anti-interferon antiserum have been previously observed. The possible role of macrophages in these interactions is explored. Depletion of peritoneal macrophages by silica at concentrations that did not markedly depress natural killer cell activity was found to inhibit the enhancement of natural killer cell activity by subsequent in vivo poly(I:C) inoculation. Inoculation with silica also seemed to abrogate the tumor inhibitory effect of poly(I:C) treatment. To determine whether effects of poly(I:C) on natural cytotoxicity and tumor growth were mediated through production of interferon, anti-interferon antiserum (alpha-IF) was inoculated prior to poly(I:C) therapy. Tumor growth appeared to be uneffected by this maneuver even though poly(I:C)-induced enhancement of natural cytotoxicity was inhibited. Taken together, both macrophages and interferon may play a pivotal role in the immune response in both a stimulatory and a suppressive capacity. Additional study on such influences may be important if in vivo manipulation of these regulatory effects is to be accomplished successfully.

Hodgkin's disease followed by mycosis fungoides in the same patient. Case report and literature review

Hodgkin's disease and mycosis fungoides are only rarely reported to occur in the same individual. The authors report a patient who initially presented with Hodgkin's disease but later died with massive visceral mycosis fungoides. This sequence of events is unique in the world's reported lymphoma experience.

Synovial fluid and blood monocytes/macrophages in rheumatoid arthritis. Influence on polyclonal activation of autologous B lymphocytes

The regulatory role of synovial fluid monocytes/macrophages from patients with rheumatoid arthritis in terms of B lymphocyte activation was evaluated by a reverse haemolytic plaque-forming cell (PFC) assay. Macrophage-depleted blood mononuclear cells (BMC) failed to respond to pokeweed mitogen (PWM). With autologous synovial fluid macrophages added, the PFC responses of macrophage-depleted BMC increased, and optimal concentration for full restoration of the PFC responses ranged from 8 to 35%. Synovial fluid mononuclear cells (SMC) as well as macrophage-depleted SMC were not able to respond to PWM. Addition of irradiated autologous blood macrophages to SMC did not increase the SMC PFC responses. It is concluded that the regulatory properties of synovial fluid macrophages do not explain the low PFC response of SMC to PWM.

Benign fibrous histiocytoma in Hodgkin's disease

A case of benign fibrous histiocytoma in a patient with previous Hodgkin's disease is reported. Benign fibrous histiocytoma consists of a proliferation of benign histiocytes in addition to inflammatory cells and occasional Reed-Sternberg-like cells. Hodgkin's disease is considered a malignant disorder of the monocyte-histiocyte cell line but also includes benign inflammatory cells as part of its histological picture. The possibility that these two entities are biologically related is considered. The pathogenic relationship between both entities is discussed in the context of the immune dysregulation associated with Hodgkin's disease.

Possible role of prostaglandin producing monocytes in the depression of mitogenic responses of blood lymphocytes following radiation therapy

Previous studies have shown that the depression of mitogenic responses of cultured blood lymphocytes following radiation therapy can largely be explained by immunosuppressive cells. In this investigation we have shown that the addition of silica, a monocyte toxic agent, to the cultures enhance the PHA- and PPD-responses of the cells at completion of irradiation. Such an effect, however, was not noted before radiation treatment was started. Similar results were obtained by adding indomethacin, an inhibitor of prostaglandin synthesis, to the cultures. The results thus indicate that immunosuppressive monocytes which mediate their activity by prostaglandins are involved in the reductions of mitogen responses of blood lymphocytes following irradiation.

On the angiostructure of lymph nodes in Hodgkin's disease. An immunohistochemical study using the lectin I of Ulex europaeus as endothelial marker

Using an extended indirect immunoperoxidase method and the lectin I of Ulex europaeus ( UEA -I), whose binding sites in lymph nodes are restricted to endothelial cells and erythrocytes, the angioarchitecture of 31 lymph nodes affected by Hodgkin's disease (HD) was demonstrated and analyzed. Compared with the normal state, the lymphocytic predominance type has a low relative vascular density, and venular endothelium is epithelioid throughout. Mixed cellularity types, especially those rich in epithelioid cells, have the lowest relative vascular density; the venular endothelium is often flat. In the sclerosing areas of the nodular sclerosis type structurel differences between capillaries, arterioles and venules vanish. Due to parenchymal atrophy and cellular depletion, relative vascular density is markedly increased in such areas, as is the case in lymphocytic depletion types. Despite all the histomorphological changes occurring in HD, the vascular system of the lymph node, surprisingly, does not undergo profound alteration. There is a positive correlation between the degree of epithelioid transformation of venular endothelium and trans-venular lymphocytic traffic. The conditions are described under which the otherwise non-reactive sinus endothelium expresses the UEA -I receptor.

The effects of prostaglandins on the proliferation of cultured human T lymphocytes

The effects of PGE2 on cultured T lymphocytes (CTC) stimulated by either Con A, PHA, or lectin-free IL-2 were studied. PGE2, in a concentration ranging from 100 to 1 ng/ml, consistently and significantly inhibited the proliferation of CTC induced by either PHA or Con A. PGF2 alpha was essentially without effect. Although the degree of inhibition of PHA-treated CTC was increased with suboptimal amounts of PHA, significant inhibition still resulted with optimal PHA concentrations. PGE2, but not PGF2 alpha, was also effective in significantly inhibiting the proliferation of IL-2-treated CTC in a dose-related fashion; however, the addition of suboptimal amounts of IL-2 did not result in greater increases in the degree of inhibition by PGE2. Depleting the CTC of either OKT-4 or OKT-8 phenotypic cells did not abrogate this PGE2 inhibitory effect, indicating that PGE2 does not suppress the proliferative response solely by the activation of suppressor cells with the OKT-8 phenotype. PGE2 also was found to inhibit the production of IL-2 by fresh lymphocytes treated by either optimal or suboptimal amounts of PHA, however, this decrease in production by PGE2 was not necessarily associated with a decrease in the proliferation of these stimulated lymphocytes. Only with low PHA concentrations, where IL-2 production was markedly reduced and barely detectable, was lymphocyte proliferation appreciably reduced by PGE2. In additional experiments, LiCl was added to PGE2 containing cultures to determine whether LiCl could modulate the inhibitor effect of PGE2 of either PHA- or IL-2-stimulated CTC. In these studies, LiCl, in concentrations of 1-10 mM was found to lessen or completely abrogate the reduced PHA proliferative response induced by PGE2. This effect was more pronounced with suboptimal concentrations of PHA than with optimal PHA amounts. In contrast, the PGE2-induced inhibition of IL-2-stimulated CTC was not modified or altered by the addition of LiCl. Thus, these results suggest that LiCl acts at the level of IL-2 production instead of IL-2 action, and that PGE2 inhibits IL-2-induced proliferation of CTC by a different or additional mechanism than for PHA-treated cells. In conclusion, these results, taken as a whole, indicate that PGE2 suppresses the proliferation of stimulated CTC by at least two different mechanisms: 1) by reducing the production of IL-2 by stimulated lymphocytes; and 2) by directly acting on the responding CTC.(ABSTRACT TRUNCATED AT 400 WORDS)

Concanavalin A-induced and spontaneous suppressor cell activities in peripheral blood lymphocytes and spleen cells from gastric cancer patients

In 173 gastric cancer patients, activities of Concanavalin-A-induced suppressor cells (Con-AS) and spontaneous suppressor cells (SpS) in peripheral blood lymphocytes (PBL), splenic vein lymphocytes (SVL), and spleen cells (SCs) were investigated. Suppressions by Con-AS in PBL were significantly effective in patients of Stages III and IV, while suppressions by SpS were effective in patients with recurrent tumors. Thus, in PBLs of cancer patients, suppressor precursors, which are considered to be activated in vitro by Concanavalin-A, seemed to appear with the advances of the disease, and SpS activities, which could be already activated in vivo, seemed to increase in the terminal stage. In SCs, increased activities of Con-AS, but normal activities of SpS, were observed, and these suppressor-cell populations consisted of glass nonadherent cells. Suppressor activities of SCs would be due to suppressor T-cells, not to other types of cells. Furthermore, Con-AS existed in the medium-sized lymphocytes, which were fractionated on the basis of cell size, while SpS in the large-sized lymphocytes. A higher proportion of T-cells, bearing Fc receptors for IgG, was observed in the larger-sized lymphocyte fractions. Cell numbers in the large-sized lymphocyte fraction tended to increase with the advances of tumors. From these results, it is suggested that higher presence of suppressor precursors and the increase of SpS activities may occur in cancer patients, depending on the tumor advancing.

Endogenous inhibition of autologous lymphocyte antibody-dependent cellular cytotoxicity

Previous reports have indicated that prostaglandins can inhibit certain immune mechanisms, particularly mitogen responsiveness and cell-mediated cytotoxicity of virus-infected or tumor cells. In this study an endogenous self-inhibitory mechanism for antibody-dependent cellular cytotoxicity (ADCC) with normal human peripheral blood mononuclear cells is described. This inhibition could be abrogated by the prostaglandin synthetase inhibitor indomethacin or by removing nylon wool-adherent cells but not platelets. ADCC inhibition was restored by adding exogenous PGE1, PGE2, or supernatant fluid from cultured plastic-adherent mononuclear cells. In contrast, supernatant fluid from adherent mononuclear cells cultured with indomethacin was not inhibitory for ADCC. These results suggest that peripheral blood mononuclear cells contain adherent cells, probably monocytes, which produce prostaglandins that inhibit the ADCC effector activity of normal peripheral blood lymphocytes. This may explain, in part, the wide variability of ADCC effector cell activity that has been reported previously. Monocyte proportions and/or activity may have profound effects on tests of ADCC effector cell activity in various disease states.

Decreased macrophage-mediated suppression of lymphocyte activation in chronic renal failure

Prostaglandin-dependent adherent cell suppressor activity was assessed in patients with end-stage renal insufficiency. Proliferative responses of uremic peripheral blood mononuclear cells to optimal concentrations of phytohemagglutinin and concanavalin A were impaired. Responses to the galactosyl-directed lectins, soybean agglutinin and peanut agglutinin, were, however, normal or supranormal. The addition of 1 microgram/ml of indomethacin, to cell cultures resulted in relatively less potentiation of blastogenic responses to the galactosyl-directed lectins in cells from uremic patients (soybean agglutinin, p less than 0.02; peanut agglutinin, p less than 0.05). Similarly, depletion of adherent cells markedly enhanced blastogenesis induced by the galactosyl-directed lectins in normal cell cultures, whereas the effect was much less pronounced (soybean agglutinin, p less than 0.02; peanut agglutinin, p less than 0.02) in uremic cells. Reduced activity of the adherent cell suppressor system in patients with renal failure might be associated with altered sensitivity of uremic lymphocytes to soluble mediators of suppression. The lymphocytes of uremic patients, depleted of adherent cells, were relatively resistant to the inhibitory action of prostaglandin E1 (0.001 microgram/ml, p less than 0.05, and 0.01 microgram/ml, p less than 0.02) on galactosyl-directed, lectin-induced mitogenesis. In contrast, dibutyryl cyclic AMP (10(-4) M), 8-bromo cyclic AMP (10(-5) M), and 3-isobutyl-1-methyl xanthine (20 micrograms/ml) inhibited both control subject and patient cultures to the same extent. Prostaglandin E1 in combination with methyl isobutyl xanthine produced, in adherent-cell-depleted control subjects, levels of cyclic AMP that were significantly higher than in cells from uremic patients (p less than 0.05). Thus, depressed adherent cell suppressor activity in patients with renal failure may result in part from impaired generation of cyclic AMP by lymphocytes.

The effects of indomethacin on in vitro peripheral blood mononuclear cell reactivity in human schistosomiasis

The peripheral blood mononuclear cell (PBMN) proliferative responses of cells from patients with schistosomiasis were studied in the presence and absence of indomethacin in the culture medium. PBMN cultures were exposed to antigenic extracts of either adult S. mansoni worms (SWAP) or cercariae (CAP), and assayed for the incorporation of tritiated thymidine. More than 70% of the 48 patients studied with SWAP and the 40 patients studied with CAP, were not substantially effected by the addition of indomethacin to the cultures. The remainder (less than 30%) was augmented more than 50% by indomethacin and comprise a group which gave initially low responses to these antigenic preparations. Further analysis indicated that in some schistosomal patients the effect of an adherent suppressor cell population may, in part, be based on a prostaglandin-mediated, indomethacin-sensitive suppressive mechanism. However, the majority of patients, most of whom display adherent suppressor cells, are unaffected by indomethacin. Apparently, other adherent cell suppressor mechanisms are responsible for the regulation observed.

Mononuclear cell function in Mycobacterium tuberculosis infected guinea pigs

In this study mononuclear cell function was studied in the lymph glands, spleen, and peripheral blood of Mycobacterium tuberculosis infected guinea pigs. Adherent cells from draining lymph nodes and spleens of infected animals spontaneously produced a factor which inhibited normal lymphocyte proliferative responses. As it has previously been shown that this factor activates a population of suppressor T cells, resident lymphocytes in the lymph nodes and spleen were examined and were shown to inhibit normal lymphocyte functions. It is suggested that adherent cells ingesting M. tuberculosis spontaneously release a suppressor cell activating factor (SCAF) which locally activates lymphocytes to become suppressor cells. Even at a time of overwhelming infection, peripheral blood adherent cells could not be shown to release SCAF and peripheral blood suppressor cells could not be identified. Although peripheral blood lymphocyte proliferative responses to PHA were normal in infected animals, their ability to produce the lymphokine macrophage inhibition factor was considerably reduced after the second week of infection. This dissociation between lymphocyte proliferation and lymphokine production is similar to that previously described in humans overwhelming tuberculosis.

Characterization of a human blood monocyte subset with low peroxidase activity

Two human monocyte subsets from the peripheral blood of healthy donors have been isolated in greater than 90% purity by countercurrent centrifugal elutration and human serum albumin gradients and their functional capabilities have been assessed. We have demonstrated that one subset ("regular" monocytes, RM) showed intense cytoplasmic peroxidase staining and contained substantial peroxidase activity. In contrast, another subset ("intermediate" monocytes, IM) stained poorly for peroxidase and had low peroxidase activity. By electron microscopic analysis combined with peroxidase localization, it was found that IM had fewer peroxidase-positive granules per cell than did RM. IM coelutriated with some lymphocytes and by cell sizing analysis were shown to be slightly smaller than RM. Functional and cytochemical analysis of these subsets indicated that IM had less activity than RM in assays such as accessory cell function for mitogen-induced T lymphocyte proliferation and antibody-dependent cellular cytotoxicity, and that fewer IM expressed OKM1 antigen and pokeweed mitogen (PWM) receptors on their membranes than did RM. The subset of IM not bearing either the PWM receptor or the OKM1 antigen had very low peroxidase activity. IM also were found to have a greater sensitivity to polyriboinosinic and polyribocytidilic acid (100 micrograms/ml)-induced secretion of interferon. There was no significant difference in the phagocytic capability, the percentage of Fc receptor-positive cells, 5'-nucleotidase activity, DR antigen expression, or the responsiveness to migration inhibitory factor of IM as compared with RM. Furthermore, it was found that the ratio of IM to RM increased after prolonged cytapheresis, which suggests that IM are more mobilizable than RM from the extravascular reservoirs of human monocytes.