Antibody-dependent eosinophil-mediated damage to 51Cr-labeled schistosomula of Schistosoma mansoni: damage by purieid eosinophils.

Abstract

After earlier observations that antibody-dependent, cell-mediated damage to 51Cr-labeled schistosomula can be ablated by pretreatment of a mixed preparation of human peripheral blood leukocytes with an anti-eosinophil serum and complement, we investigated the cytotoxic effects of eosinophil-enriched cell preparations. Preparations containing up to 98.5% eosinophils and devoid of neutrophils were effective in mediating antibody-dependent damage to schistosomula. Preparations enriched in mononuclear cells or in neutrophils, and devoid of eosinophils, were inactive. Eosinophils from some patients with eosinophilia induced by schistosomiasis were less active on a cell-to-cell basis than cells from normal individuals. The possibility that such cells were initially blocked by immune complexes was considered, and it was found that reasonable cytotoxicity by purified eosinophils from patients with eosinophilia could be generated by overnight cultures. A possible requirement for cooperation between eosinophils and other cell types was also studied. Lymphocytes, neutrophils and monocytes failed to enhance eosinophil-mediated cytotoxicity. These results provide further evidence that the eosinophil is the only cell in man responsible for antibody-dependent, complement-independent damage to schistosomula in vitro. Eosinophils from individuals, however, differ in their cytotoxic potential by a mechanism yet to be elucidated. The possible relationship of these findings to immunity in vivo is discussed.

Role of Cell-generated Hydrogen Peroxide in Granulocyte-mediated Killing of Schistosomula of Schistosoma mansoni In Vitro

“…Furthermore, many helminths have developed elaborate mechanisms to evade host resistance, such as masking their surface or acquisition of host antigens (6). Recently several in vitro systems describing the interaction of the components of the host immune system and multicellular parasites have been developed to elucidate the mechanisms of resistance against these organisms (7)(8)(9)(10). Initially human eosinophils were demonstrated to damage the multicellular schistosomula of Schistosoma mansoni in the presence of specific anti-parasite antibodies (7).…”

Role of Immune Complexes from Pacients with Different Clinical Forms of Schistosomiasis in the Modulation of In Vitro Granuloma Reaction

“…Recent studies have demonstrated that several immunoregulatory mechanisms may be operative in human schistosomiasis. The possible interference of IC with cellular defense mechanisms against S. mansoni has been suggested by others (Butterworth et al 1977, Kamal & Higashi 1982. Afterwards, studies on in vitro granuloma reaction have shown that IC obtained from sera of INT patients are able to suppress INT patients PBMC reactivity to PB-SEA and PB-SWAP (Goes et al 1991, Rezende et al 1993).…”

Suppressing Effects of Purified Eosinophils Derived From Guinea Pigs Sensitized With Ascaris Antigen on Lymphocyte-Blastformation

“…Whether or not Eos emigration works for protection against or offers a comfortable environment for worms may be one of the important problems to be solved. Butterworth et al (1977) conceived that Eos had parasiticidal properties when working together with specific antibodies in experimental schistosomiasis in mice.…”