Immune cytotoxic activity of human eosinophils againstTrichinella spiralisnewborn larvae

Abstract

The ability of human eosinophils to kill the newborn larvae (NBL) of Trichinella spiralis of different maturation status, in the presence of antibody, was studied. A cytotoxic in vitro test was performed using NBL less than 2 h of age (NBL2) or NBL maintained in culture at 37 degrees C for 20 h (NBL20), peripheral blood eosinophils, anti-Trichinella serum and human fresh serum as source of complement. Under these experimental conditions eosinophils from normal individuals attached to NBL2 as well as to NBL20 but only the latter were killed. On the other hand, eosinophils from volunteers with eosinophilia killed NBL regardless of larval age. Neither adherence nor significant mortality was observed in the absence of immune serum. These results indicate that NBL maturation and eosinophil activation status are crucial for antibody-dependent cellular cytotoxic reaction (ADCC).

Contrasting roles for IL‐10 in protective immunity to different life cycle stages of intestinal nematode parasites

“…In summary, the data presented here demonstrate that IFN-+ is crucially involved in protection against newborn larvae, but does not affect the expulsion of adult worms. Mechanisms of IFN-+ -mediated immunity to newborn larvae may include enhanced cytotoxic killing by eosinophils, granulocytes and activated macrophages [45][46][47][48][49].…”

CCR3 Is Required for Tissue Eosinophilia and Larval Cytotoxicity After Infection withTrichinella spiralis

“…7). Although several studies indicated that eosinophils could kill Ts larvae in vitro (27)(28)(29), in vivo studies have generated conflicting results on this issue. Grove et al (23) found that suppression of the eosinophil response in CF1 outbred mice with an anti-eosinophil serum resulted in increased numbers of Ts larvae, counted after digestion of the host tissues.…”

“…The intestinal immune response to Ts is also accompanied by eosinophilia, but the eosinophil is not thought to be essential for the elimination of adult worms after a primary infection (19,21,(23)(24)(25)(26). Moreover, although both human and mouse eosinophils kill Ts larvae in vitro (27)(28)(29), their importance in clearance of larvae that are released by adult worms in vivo remains controversial based on the results of studies in mice (23)(24)(25)(26). Depletion of eosinophils in Ts-infected mice with a rabbit antieosinophil serum resulted in increased larval burdens (23), whereas eosinophil depletion by an mAb that blocked the actions of IL-5, a cytokine essential for normal eosinophil responses, had no effect on larval burden (24).…”

Differences in cellular immune responses of mice BALB/c to low and high infective doses of Trichinella spiralis

“…infection, the proliferation of splenic B cells was stimulated only at the muscle phase, from day 45 p.i., when also seroconversion for specific antibodies was recorded (Dvorožňáková et al, 2010). T-cells play a central role in immune and inflammatory responses against Trichinella infection (Wakelin & Grencis, 1992;Dvorožňáková et al, 2005Dvorožňáková et al, , 2012. Trichinella spp.…”

“…Numbers of muscle larvae in mice with the light infection were 40-fold lower than were the parasite burden in mice with the heavy infection. Mechanism of IFN-γ mediated immunity to newborn larvae may include enhanced cytotoxic killing by eosinophils, granulocytes and activated macrophages (Venturiello et al, 1995). Kołodziej-Sobocińska et al (2006 found an increased metabolic activity of peritoneal macrophages during the first months after infection.…”