Raúl Villegas Silva

Cytokine expression in CD4+ cells exposed to the monocyte locomotion inhibitory factor produced by Entamoeba histolytica

Entamoeba histolytica produces monocyte locomotion inhibitory factor (MLIF), a pentapeptide with in vitro and in vivo anti-inflammatory properties. MLIF may interfere with leukocyte migration, disturbing the balance of pro- and anti-inflammatory cytokines secreted by CD4+ T lymphocytes. We evaluated the effect of MLIF on expression of pro- and anti-inflammatory cytokines in human CD4+ T lymphocytes. Regulatory cytokines [interleukin-1 beta (IL-1β), IL-2, interferon gamma (IFN-γ), IL-5, IL-6, and IL-10] were studied by enzyme-linked immunosorbent assay method in CD4+-cell supernatant fluids. Proinflammatory cytokines were produced per se by MLIF (IL-1β, IL-2, and IFN-γ) and also anti-inflammatory cytokines (IL-5, IL-6, and IL-10) with 1-phorbol-12 myristate-13 acetate + MLIF; the IL-1β, IFN-γ, IL-5 and IL-6 production was inhibited but not that of IL-10 which disclosed increase in its expression. MLIF disturbs the pro- and anti-inflammatory balance, and it induces inhibition of IL-1β (principal proinflammatory cytokine) and increases IL-10 (prototype of an anti-inflammatory cytokine).

Does Entamoeba dispar Produce Monocyte Locomotion Inhibitory Factor (MLIF) Like Entamoeba histolytica

Entamoeba histolytica (Schaudinn, 1903) and Entamoeba dispar (Brumpt, 1925) are two morphologically identical protozoan parasites of the human intestinal tract. The former is a potentially invasive microrganism capable of causing important intestinal damage and extraintestinal disease, while the latter is considered a noninvasive commensal. Indistinguishable under the microscope, E. histolytica and E. dispar can, however, be separated biochemically, immunologically, and genetically into two different protozoan species (1). Several strains of axenically grown E. histolytica have been shown to produce a heat-stable, small (582 Da) pentapeptide [monocyte locomotion inhibitory factor (MLIF)] with in vitro as well as in vivo anti-inflammatory properties (i.e., inhibition of leukocyte locomotion, respiratory burst, nitric oxide production, DNCB skin hypersensitivity, Rebuck window inflammation sequence, etc.) that selectively affect various types of leukocytes (2– 4).We now studied whether E. dispar produces MLIF.