Analysis of immune lesions in neurocysticercosis patients: central nervous system response to helminth appears Th1-like instead of Th2.

Neurocysticercosis (NCC) caused by the helminth Taenia solium is the most common parasitic infection of the human central nervous system (CNS) worldwide. Because clinical symptoms are associated with localized immunological responses in the brain, characterization of these responses are pivotal for understanding the pathogenesis of cysticercosis. Immunohistochemical analysis of brain specimens from several patients with cysticercosis revealed at least four types of immune responses, including: (i) an antibody response (IgM + plasma cells), (ii) a predominant NK response, (iii) an infiltrate with abundant macrophages and granulocytes, and (iv) an intense infiltrate with a predominance of macrophages and T cells. The intensity and type of immunity appeared to be associated somewhat with the parasite's viability and anatomical location. In most of the lesions, cell mediated responses were evident and proinflammatory cytokines including IL12 predominated. Moreover, IL4 was undetectable in the immune infiltrates. Thus, the CNS response to this helminth, unlike the systemic response, is predominately Th1-like.

Antigen induced eosinophilia protects gerbils (Meriones unguiculatus) against experimental amebic abscess of the liver.

While the normal human eosinophil is destroyed in vitro by virulent Entamoeba histolytica, notwithstanding the presence of antibodies and complement, activated eosinophils promptly destroy the parasite even though succumbing in the process as well. To study the possible in vivo participation of eosinophils in invasive amebiasis, we compared the induction of experimental amebic abscess of the liver (EAAL) in gerbils (Meriones unguiculatus) previously made eosinophilic (532 +/- 80 eosinophils/mm3) through Toxocara canis antigen injection and normal control gerbils (101 +/- 15 eosinophils/mm3). Shortly (6 and 24 h) after intraportal injection of 10(5) virulent E. histolytica, the ratio of gerbils with EAAL, as well as the number and size of the abscesses was comparable in eosinophilic and control gerbils. At 96 h post-inoculation, the ratio of animals with EAAL was still the same in both groups, yet number and size of abscesses were significantly (p < 0.05) smaller in eosinophilic gerbils. The actuarial EAAL survival curve up to 45 days post-amebic inoculation was significantly (p < 0.05) shifted to the right in eosinophilic gerbils. No significant changes in IL-5 levels were recorded throughout these experiments. The results suggest that antigen-induced eosinophilia may exert a protective effect against EAAL in gerbils. It is speculated that a less overwhelming EAAL strategy--more akin to human amebic abscesses--may reveal this protective effect more clearly.