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Identifier

000348210

Title

Επίδραση ανοσοτοξικών παραγόντων σε in vitro μοντέλο ανοσοποίησης

Author

Βλατά, Ζαχαρένια

Thesis advisor

Τζανακάκης, Γιώργος

Reviewer

Κραμποβίτης, Ηλίας
Τσατσάκης, Αριστείδης
Πλαϊτάκης, Ανδρέας
Σπαντίδος, Δημήτριος
Σουρβίνος, Γεώργιος
Ζαφειρόπουλος, Αλέξανδρος

Abstract

Mycotoxins are fungal secondary metabolites that have been associated with severe toxic effects to humans and animals. The potential presence of mycotoxins in foods renders them a public health hazard and their toxicity needs to be better understood. In the present study we used human peripheral blood mononuclear cells (PBMC) to address the in vitro immuno-cytopathicity of two selected mycotoxins, Τ-2 toxin and Zearalenone (ZEA), as well as one neurotoxin Botulinum-Α (BoNT-A) (BOTOX). Here we report the effects of these toxins on the proliferation and cell death patterns of untreated or mitogen-activated PBMC. T-2 toxin is a type A trichothecene mycotoxin with high immunotoxicity. Investigating the effects of T-2 at sub-toxic (0.1ng/ml) and toxic (10ng/ml) levels on PBMC we observed no direct influence on untreated lymphocytes. In the phytohemagglutinin (PHA) - activated cultures, however, the toxic dose of T-2 totally inhibited the PHA-induced T cell proliferation and caused early apoptosis peaked 8 hours after exposure. Transient elevation of intracellular calcium ion levels (Ca2+) was noted, prior to apoptosis. The two main T lymphocyte subsets, CD4+ and CD8+, showed a positive response to T-2 at 8 hours followed by a sharp decline after 96 hours, which were confirmed by corresponding changes of naïve (CD45RA+) and memory/effectors (CD45RO+) subpopulations. T-2 at sub-toxic doses appeared to exhibit co stimulatory properties to PHA-stimulated cells. These results suggest that the immunotoxicity of T-2 is related to the mechanism of activation-induced cell death (AICD) of T lymphocytes. ZEA is a non-steroidal estrogenic mycotoxin with a relatively low toxicity. We investigated the effects of ZEA at two limited concentrations (30μg/ml and 1μg/ml) on human PBMC. The higher concentration of 30μg/ml ZEA totally inhibited the T and B lymphocyte proliferation induced from PHA- and pokeweed mitogen (PWM) respectively. By examining the apoptosis and necrosis profiles using flow cytometry, we showed that ZEA exerted a distinct necrotic effect on PBMC, irrespective of mitogen stimulation, whereas apoptotic activity was less evident. Increased intracellular Ca2+ levels were observed only in the monocyte/granulocyte gated cells. Using the lysosomal inhibitors phenylmethyl sulfonyl fluoride (PMSF) and ammonium chloride, we demonstrated that ZEA-induced necrosis was inhibited by both PMSF at 0.05mM and ammonium chloride at 1 and 10mM, whereas apoptosis was less affected. Expose of PBMC to 1μg/ml ZEA did Περίληψη 9 not alter the viability of the cells. Our results suggest that high ZEA concentrations in the blood can induce cytotoxic effects that merit further investigation. BOTOX, a neurotoxin Botulinum A, has become a standard therapy for many neurological disorders. In this study we examined the effects of BOTOX and tetanus neurotoxin on PBMC from patients who had been treated with BOTOX. We observed low immunotoxicity of BOTOX at tested doses, as were shown by the limited T- and B- cell responses and the absence of detectable antibodies cross-reacting with tetanus. However, exposure of both neurotoxins to PBMC from patients with anti-tetanus antibodies, BOTOX appeared to exert co stimulatory effect to tetanus-stimulated cells. Moreover, BOTOX affected the T lymphocyte subsets where we observed reduction of the naïve (CD45RA+) subpopulation and an increase of the effectors/memory (CD45RO+) subpopulation at the same time. These observations indicate the need for a more detailed study on the effects of repeated use of BOTOX on the immune system. The results from this study provide useful information about the mechanisms by which mycotoxins and BOTOX can affect the immune system and induce immunotoxicity, providing potential on effective management and treatment of these toxins.

Physical description

176 σ. : πιν. ; 30 εκ.

Language

Greek

Subject

Mycotoxins

Μυκοτοξίνες

Issue date

2007-12-14

Collection

School/Department--School of Medicine--Department of Medicine--Doctoral theses

Type of Work--Doctoral theses