Destruction of normal human eosinophils by Entamoeba histolytica

Abstract

We evaluated the in-vitro interaction of normal human eosinophil leucocytes and a virulent strain of Entamoeba histolytica (HM1-IMSS) in the presence of immune serum. At a 10:1 (eosinophil:amoeba) ratio a significant time-dependent destruction of eosinophils was found from the first hour onward, and a similar, albeit weaker, cytopathic effect was found in the 200:1 ratio mixtures, with some delay in the microscopic evidence of such effect. Results were unaffected by serum factors, and amoebae emerged virtually unharmed throughout these experiments, again regardless of the presence of serum factors. These results indicate that, as with neutrophil leucocytes, virulent E. histolytica is capable of destroying normal human eosinophils in vitro.

Entamoeba histolyticaelectrondense granules secretion in vitro and in vivo: Ultrastructural study

“…In these lesions macrophages, polymorphonuclear leukocytes and eosinophils are the most frequent inflammatory cells. Previous studies have reported that these cells may be damaged and phagocyted by E. histolytica trophozoites (López-Osuna and Kretschmer, 1989). Likewise, in our study numerous granules characteristic of eosinophils were identified in the cytoplasmic vacuoles of trophozoites, suggesting that these cells were endocyted by the parasite.…”

Eosinophils, HLA and amebic disease

“…Not to our surprise, normal (i.e. non-activated) human eosinophils -just like their alleged kin, the neutrophils -easily succumbed to the lytic effect of the voracious amebas, the presence of anti-amebic antibodies notwithstanding [3]. In contrast, activated eosinophils turned out to be quite efficient in destroying the parasite, although ultimately succumbing in the process as well.…”

Does the eosinophil have a protective role in amebiasis?

“…Moreover, axenically grown trophozoites of E. histolytica kill in vitro normal human neutrophils and eosinophils (not-withstanding the aid by antibody and complement), normal monocytes and lymphocytes, without suffering changes in their own viability (Jarumilinta & Kradolfer 1964, Artigas et al 1966, Guerrant et al 1981, Salata et al 1985, 1987, López-Osuna et al 1986, López-Osuna & Kretschmer 1989 fectively destroying virulent amebas, even though finally succumbing in the process as well (Salata et al 1985). In our laboratory we found that the same occurs with activated human peripheral blood eosinophils (López-Osuna et al 1992).…”