Alternaria toxins as risk factors for cellular immunity disorders and cytokine profile imbalance (based on an in vivo experimental model)

Possible contamination of food products with Alternaria toxins determines the need to investigate immunotropic impacts of toxic metabolites to clarify the dose-dependent effects of their exposure.

The aim of the study was to evaluate the effect of tenuazonic acid (TeA) and Alternaria toxins extract as risk factors causing cellular immunity disorders and cytokine profile imbalance in rats in an in vivo experiment.

The experiment was conducted on three groups of male Wistar rats with an average body weight of 238 g. The animals received a balanced semi-synthetic feed and purified water (ad libitum). The rats of the control group (1st group) were administered a single intragastric injection of a 10 % aqueous solution of ethyl alcohol (solvent) in the amount of 3 ml/kg body weight (b.w.); the 2nd group – a solution of the pure TeA at a dose of 30 mg/kg b.w.; the 3rd group – a solution of the extract of the cultivation medium of the producer fungus Alternaria alternata, containing a mixture of Alternaria toxins: TeA (at a dose of 30 mg/kg b.w.), alternariol (AOH) (0.276 mg/kg b.w.) and its methyl ester (AME) (0.902 mg/kg b.w.), tentoxin (TEN) (0.018 mg/kg b.w.). The solutions administered to rats in groups 2 and 3 contained an amount of ethyl alcohol adequate to that in the control group. Twenty-four hours after the solutions were administered the rats were removed from the experiment by decapitation with collection of blood samples. The hematological profile was determined on a Coulter ACT TM 5 diff OV hematological analyzer. Expression of CD45R, CD3, CD4, CD8a, CD161 receptors on rat peripheral blood lymphocytes was determined by direct immunofluorescence staining of whole blood cells using a panel of monoclonal antibodies on an FC-500 flow cytometer. The content of cytokines IFN-γ (interferon-γ), IL-1β (interleukin 1β), IL-2, IL-5, IL-6, IL-10, IL-17A, MCP-1 (monocyte chemoattractant protein-1), MIP-1α (macrophage inflammatory protein-1α) and TNF-α (tumor necrosis factor-α) in blood plasma was determined by multiplex immunoassay on a Luminex 200 analyzer.

The results of the study indicate a proinflammatory effect produced by intragastric administration of TeA to rats, both as a monocomponent and as part of the extract of the Alternaria alternata culture medium. The Alternaria toxins used in the study are capable of inducing systemic inflammatory reactions identified by an increase in the content of B-lymphocytes responsible for humoral immunity and an increase in the levels of proinflammatory, proapoptogenic cytokines in the blood plasma: TNF-α, IL-1β, IFN-γ, IL-6, IL-10, IL-2, IL-5, IL-17A and chemokines MIP-1α and MCP-1. Introduction of TeA leads to a decrease in the levels of anti-inflammatory IL-5 and IL-10, which may be a consequence of a decrease in the activity of Treg (T-regulatory) lymphocytes confirmed by a decrease in the IL-10/IL-17A ratio.