Maria Concetta Berlinghieri

Different effects of bacterial lipopolysaccharide on superoxide anion production by macrophages from normal and tumor-bearing rats

Bacterial endotoxins or lipopolysaccharides (LPS) exhibit a wide range of modulatory activities on immunocompetent cells. Among the numerous effects of LPS on macrophages, an enhancement of superoxide anion (O2-) release has been reported. In previous studies carried out on tumor-bearing rats, it was found that several functions of peritoneal macrophages such as phagocytic, microbicidal and antiviral activities were depressed. In this paper we evaluated the spontaneous or phorbol myristate acetate (PMA)-induced production of superoxide anion by macrophages from tumor-bearing rats with respect to controls. Moreover, the effect of in vitro priming with LPS on O2- production by the same cells was studied. It was found that the pattern of superoxide release by macrophages from tumor-bearing rats is significantly different from controls. Preincubation of macrophages from normal rats with LPS enhanced the spontaneous and PMA-induced production of O2-. In contrast, the same concentrations of LPS did not prime macrophages from tumor-bearing rats.

The restoration of impaired macrophage functions using as immunomodulator the Corynebacterium granulosum-derived P40 fraction

Many microorganisms and compounds of microbial origin exhibit immunomodulatory activities and have been extensively used in immunotherapy of experimental animal tumors and in patients with neoplasia. In this paper we describe the effect of the C. granulosum-derived P40 fraction on the growth and metastatization of the transplantable epithelioma T8 of Guèrin. Moreover, we evaluated the effect of P40 treatment on several depressed macrophage functions of tumor-bearing rats. In particular, the phagocytic and chemotactic activities of such cells were studied, as well as the antiviral intrinsic and extrinsic activities against HSV-1 and the anti-Toxoplasma gondii activity. All these functions were depressed in untreated tumor-bearing rats. Administration of a single intravenous injection of P40 fraction led to the restoration of all depressed macrophage activities to normal values. In particular, the possibility of restoring the antimicrobial activity of macrophages from tumor-bearing rats by treatment with this immunomodulator is of great concern when one considers the increasing incidence of opportunistic infections in immunocompromised hosts. Results are discussed in terms of both the possible mechanism of action of P40 and of its possible target cells.

Meropenem: effects on human leukocyte functions and interleukin release

Modifications of the immune response have been reported for a number of antimicrobial agents following both in vivo and in vitro experiments. Present results were obtained from in vitro incubated human polymorphonuclear cells (PMN) and monocytes treated with meropenem, a novel carbapenem antibiotic. Only the highest concentrations of meropenem (50-200 microg/ml) significantly reduced the phagocytic activity and unstimulated superoxide release of neutrophils after 1 h of incubation. Moreover meropenem (100 and 200 microg/ml) reduced PMA-stimulated superoxide release by PMN after 1 h of incubation. Only the highest concentration used (200 microg/ml) was found to reduce significantly superoxide release by PMA-unstimulated and -stimulated PMN incubated for 2 h. Meropenem did not affect some of the PMN functions studied (killing of Candida albicans, chemotaxis and glucose consumption) over a broad range of concentrations (5, 10, 20, 50, 100, 200 microg/ml). The leukocyte viability did not change even at the highest antibiotic concentration used, as showed by the trypan blue exclusion test. The LPS-induced release of IL-1alpha, IL-6 and IL-8 from isolated monocytes was not impaired by meropenem (100 and 200 microg/ml), that significantly reduced TNFalpha stimulated by LPS, after 4 h of incubation. In conclusion our data suggest that therapeutically relevant concentrations (5-20 microg/ml) of meropenem did not modify substantially the viability and the functions of human leukocytes.

Inhibition of normal rat macrophage functions by soluble tumor products

SummaryThe phagocytic and chemotactic activities of normal rat peritoneal macrophages were inhibited by sera from tumor-bearing rats (TBR) and 3 M KCl extracts of tumor mass. However, sera from Corynebacterium parvum- or Listeria monocytogenes-treated TBR did not inhibit phagocytosis. On the other hand, sera from C. parvum-treated, but not from L. monocytogenes-treated TBR still inhibited the chemotactic response of the normal macrophages. Furthermore, 3 M KCl extracts of tumors from C. parvum-treated TBR did not inhibit phagocytosis and chemotactic response of the same cells. Similar results were obtained with extracts of tumor masses from L. monocytogenes-treated rats. It is suggested that treatment with bacterial immunomodulators can influence the release from neoplastic cells of soluble products influencing normal macrophage functions.

Impairment of immunological functions in genetically epilepsy-prone rats.

1. In genetically epilepsy-prone rats (GEPR-9s), which represent a natural genetic model of epilepsy, we observed that the number of peritoneal macrophages was significantly lower with respect to normal rats, and that some functional parameters (i.e. phagocytosis and intracellular killing) of these macrophages were impaired. 2. The count of lymphocyte populations showed a predominance of T-helper over T-cytotoxic/suppressor both in the spleen and lymph nodes. Moreover, an increased T-cell/B-cell ratio was observed in GEPR-9s. Flow cytometry revealed that GEPR-9s spleens possessed a large percentage of T-helper cells in comparison to normal rats. 3. By using concanavalin A-induced proliferation of GEPR-9s cultured lymphocytes, we have shown increased functional activation. 4. We suggest that the alterations in T-cell functions in GEPR-9s could be due to the involvement of the neuroendocrine system in the modulation of immunity, in the shift between Th1 and Th2, and in the activation of stress response.

Effect of bacterial endotoxin on lipoxygenase and cyclo-oxygenase metabolites by rat neutrophils and correlation with cellular functional parameters.

SummaryThe effect ofSalmonella enteritidis endotoxin on in vitro rat neutrophil cyclo-oxygenase and lipoxygenase metabolism, phagocytic activity, superoxide (O2-) generation, and microbicidal activity was investigated. Incubation of polymorphonuclear leukocytes (PMN) with 5, 25, and 50 µg of endotoxin significantly enhanced synthesis of immunoreactive (i) leukotriene (LT)C4/D4 and thromboxane (Tx)B2 (P < 0.001) as compared to control cells. Endotoxin 5 µg/ml produced optimal stimulation of the arachidonic acid metabolites. Calcium ionophore, A23187, significantly enhanced iLTC4/D4 and iTxB2 synthesis more than that elicited with endotoxin. Although phagocytic function was not significantly altered by endotoxin, intracellular killing ofC. albicans demonstrated enhanced microbicidal activity at 5 µg/ml of endotoxin. Superoxide generation was significantly enhanced in neutrophils stimulated with phorbol myristate acetate (PMA). Endotoxin (5 µg/ml) further potentiated superoxide generation by these cells when stimulated by PMA. These findings demonstrate that endotoxin directly enhances neutrophil iLTC4/D4 and iTxB2 synthesis. The enhanced arachidonic acid metabolism elicited by endotoxin in these cells parallels increased microbicidal activity and superoxide generation.

Immunoprofilo nei pazienti affetti da psoriasi

SummaryThe most recent literature’s evidences on pathogenic mechanisms of psoriasis have been presented. They involve genetic factors, immune-response alteration, cytokines hyper-production and can be triggered by environmental stress. Thus, psoriasis may evolve in different and subsequent phases with different clinical behavior. The laboratory can support the early diagnosis and may address a personalized therapeutic treatment performing the evaluation of the immunoprofile of the patient. This consists in the measurement of the number and the activity of lymphocytes involved in this disease, for instance T-reg, and in the evaluation of circulating levels of cytokines, for instance IL-1, IL-17, TNFα

Effect of oral administration of different combinations of killed bacteria on some depressed macrophage functions in tumor-bearing rats

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Teicoplanin reduces in-vitro reactivity and murine lethality of Salmonella minnesota R595 lipopolysaccharide

, through accurate and reproducible methodologies in order to perform a correct diagnosis and evaluate the efficacy of the personalized therapy.

Effect of RO 23-9424, cefotaxime and fleroxacin on functions of human polymorphonuclear cells and cytokine production by human monocytes

In the present study, we compared the ability of different bacterial species administered orally in various combinations to restore some depressed peritoneal macrophage functions in tumor-bearing rats. Phagocytosis, killing of Candida albicans and chemotactic response of resident peritoneal cells from treated tumor-bearing rats were influenced by different associations of bacteria. In particular, when Staphylococcus aureus was administered together with other bacterial species, the phagocytic activity of peritoneal cells was restored to normal values, and intracellular killing of C. albicans was enhanced. The results are discussed in relation to the possible influence of mucosal bacterial flora on the level of activation of peritoneal macrophages. The possibility that bacterial species can influence in various ways immunocompetent cells in relation to the different chemical composition of some common structures is also discussed.