R. Gonzalez-Cabello

Effect of silibinin and vitamin E on restoration of cellular immune response after partial hepatectomy

Our aim was to study the antioxidant and immunomodulatory effect of silibinin and vitamin E on the early postoperative course in rats that had undergone a partial hepatectomy (PHX). Male Wistar rats that were treated with silibinin (50 mg/b.w.kg i.p.) and/or vitamin E (500 mg/b.w.kg p.o.) were randomised to undergo 70% PHX. At 72 h after operation, Concanavalin A (Con-A) induced lymphocyte proliferation, and lipopolysaccharide (LPS) induced interleukin-1 (IL-1) mitogenicity and tumour necrosis factor-alpha (TNF-alpha) cytotoxicity were measured in the spleen. In addition, total free radical scavenger capacity of the liver was analysed. In PHX animals, Con-A induced lymphocyte proliferation was significantly decreased, and both LPS induced IL-1 and TNF-alpha activity were significantly increased as compared to Sham treated animals. Treatment with silibinin and vitamin E synergistically restored both lymphocyte proliferation (P<0.01) and cytokine activity (P<0.001) in PHX animals. In addition, silibinin and vitamin E synergistically (P<0.001) restored total hepatic free radical scavenger capacity as well as serum levels of AST and gammaGT, that were all markedly decreased in PHX animals. Our results suggest that preoperative treatment with silibinin and/or vitamin E modulates the cellular immunoresponse and restores impaired liver function following PHX, presumably through their antioxidant capacity. This may explain their beneficial effects on the postoperative course of liver repair.

Effector activity of OKT4+ and OKT8+ T-cell subsets in lectin-dependent cell-mediated cytotoxicity against adherent HEp-2 cells

The role of OKT4+ and OKT8+ T-cell subsets was studied in lectin-dependent cell-mediated cytotoxicity (LDCC) against adherent HEp-2 human epipharynx carcinoma target cells. LDCC was evaluated by detachment from the monolayer of [3H]thymidine prelabeled HEp-2 cells in a 24-hr assay with a concanavalin A (Con A) dose of 25 microgram/ml at effector:target cell ratios of 5:1, 25:1, and 50:1. Under these conditions but without Con A considerable natural cell-mediated cytotoxicity (NCMC) was not elicited; however, the cytotoxicity was significantly augmented in the presence of Con A (=LDCC) by sheep erythrocyte rosette-forming T lymphocytes and by both OKT4+ and OKT8+ T-cell fractions. LDCC activity by isolated OKT8+ T cells was superior to that by OKT4+ T cells and unfractionated T lymphocytes. By contrast, addition of either OKT4+ or OKT8+ T cells together with unfractionated T lymphocytes, or OKT4+ and OKT8+ T cells mixed at ratios of 1:1, 1:2, and 2:1, to target cells did not result in major differences in comparison of LDCC activities by these mixed effector cell populations with each other or with that by unfractionated T lymphocytes. Parallel studies were carried out to determine the effect of OKT4+ and OKT8+ T-cell subsets on the Con A-induced proliferation of peripheral blood mononuclear cells (PBMC). While OKT8+ T cells inhibited the mitogenic response to Con A, OKT4+ T lymphocytes had no major effect. A higher responsiveness of the OKT8+ to OKT4+ T-cell subset in LDCC to HEp-2 targets and in Con A-induced lymphocyte proliferation is suggested.

Ketoconazole in vitro inhibits mitogen-induced blastogenesis, antibody-dependent cellular cytotoxicity, natural killer activity and random migration of human leukocytes

Ketoconazole at concentrations of 1-10 micrograms/ml dose dependently inhibits mitogen-induced blastogenesis, antibody-dependent and spontaneous cytotoxic (natural killer) activity of human lymphocytes and random migration of human leukocytes. Lectin-dependent cytotoxic activity is not affected by the drug.

The Effect of Heat-Inactivated Helicobacter pylori on the Blastogenic Response of Peripheral Blood Mononuclear Cells of Patients with Chronic Urticaria

Background:Helicobacter pylori, the most important etiologic factor of gastritis and peptic ulcer, has recently been associated with several extradigestive diseases. Previous studies reported conflicting results on H. pylori eradication in chronic urticaria, in that some studies showed a benefit, while others found no effect. Methods: Peripheral blood mononuclear cells of 24 chronic urticaria patients (13 seropositive/11 seronegative for H. pylori) and 18 healthy controls (9 seropositive/9 seronegative) were stimulated with whole heat-inactivated H. pylori (8 × 105, 8 × 106 and 8 × 107 bacteria/well), phytohemagglutinin (2 µg/ml) and pokeweed mitogen (5 µg/ml). The proliferative response was determined by 3H-thymidine incorporation. Helicobacter-specific IgG antibody response was determined by ELISA. Results: There were significantly higher proliferative responses to various concentrations of whole heat-inactivated H. pylori antigen in 6- to 7-day cultures of peripheral blood mononuclear cells of chronic urticaria patients compared to healthy controls. We found a tendency to exhibit a higher proliferative response to either Helicobacter antigens or mitogens in seropositive compared to seronegative patients. Conclusion: Our results support the hypothesis that there is an increased lymphocyte reactivity in chronic urticaria, perhaps further enhanced by the presence of H. pylori which, therefore, may be involved as a trigger in the pathogenesis of chronic urticaria.

Depressed natural and lectin-dependent cell-mediated cytotoxicity against adherent HEp-2 cells in patients with systemic lupus erythematosus.

Natural cell-mediated cytotoxicity /NCMC/ was evaluated using human adherent 3H-thymidine-prelabelled HEp-2 epipharynx carcinoma cells as targets at 50:1 effector-target cell ratio in a 24 hr assay. For lectin-dependent cell-mediated cytotoxicity /LDCC/ studies cultures contained also 25/micrograms/ml concanavalin A /Con A/. Peripheral blood mononuclear cells /PBMC/ of nine patients with active systemic lupus erythematosus /SLE/ failed to exert NCMC or LDCC against HEp-2 targets. In contrast, an increased adherence /decreased detachment from the monolayer/ of HEp-2 target cells was observed in the presence of PBMC from SLE patients that was further promoted by the addition of Con A during LDCC assay.

Depressed lectin-dependent cell-mediated cytotoxicity against adherent HEP-2 cells in patients with carcinoma of the uterine cervix

SummaryLectin-dependent cell-mediated cytotoxicity of peripheral blood mononuclear cells from patients with uterine cervix carcinoma was evaluated using human adherent 3H-TdR-prelabeled HEp-2 epipharynx carcinoma cells as targets at a 50:1 effector-target cell ratio with 25 ώg concanavalin A/ml in a 24-h assay. Peripheral blood mononuclear cells from 13 patients with cervical carcinoma in stage IV failed to exert cytotoxicity against HEp-2 targets. In contrast, an increased survival (decreased detachment from the monolayer) of HEp-2 cells was observed in the presence of peripheral blood mononuclear cells from patients, this being significantly enhanced by addition of concanavalin A during the lectin-dependent cell-mediated cytotoxicity assay.

Contrasting effects of RNA and protein synthesis blocking on natural and lectin-dependent cell-mediated cytotoxicity against adherent HEp-2 cells

In this study, earlier observations2,9 concerning the independence of both natural (NCMC) and lectin-dependent cell-mediated cytotoxicity (LDCC) from DNA synthesis have been confirmed. In addition, blocking of RNA synthesis by actinomycin D and of protein synthesis, reversibly by puromycin (PM) and irreversibly by emetine (EM) had different effects on NCMC and LDCC against3H-thymidine-prelabeled HEp-2 target cells. Similarly to the Con A-induced proliferation of lymphocytes, LDCC activity was also inhibited by blocking of RNA and protein synthesis. NCMC to HEp-2 target cells was not affected by blocking of RNA synthesis, while both PM and EM strongly enhanced NCMC activity.

Effect of Fc receptor blocking on human natural and lectin-dependent cell-mediated cytotoxicity against adherent HEp-2 cells

The effect of Fc receptor (FcR) blocking by aggregated human gamma-globulin (AGG) was studied on natural (NCMC) and lectin-dependent cell-mediated cytotoxicity (LDCC) against adherent HEp-2 human epipharynx carcinoma target cells. Cytotoxicity was measured by detachment from the monolayer of [3H]TdR-prelabelled HEp-2 cells. LDCC was evaluated in a 24 h assay at 50:1 effector-target cell ratio in the presence of 25 micrograms/ml concanavalin A (Con A). Under these conditions but without Con A considerable NCMC was not elicited by normal lymphocytes. FcR blocking by AGG treatment of effector cells resulted in a significant NCMC activity to HEp-2 targets. In contrast, AGG treatment profoundly depressed LDCC. Monocyte depletion of effector cells had no major influence on the effect of AGG on NCMC and LDCC activities. An interference of FcR blocking by AGG and LDCC in response to Con A is suggested.