Cellular gene expression induced by parasite antigens and allergens in neonates from parasite-infected mothers.

Prenatal exposure to parasite antigens or allergens will influence the profile and strength of postnatal immune responses, such contact may tolerize and increase susceptibility to future infections or sensitize to environmental allergens. Exposure in utero to parasite antigens will distinctly alter cellular gene expression in newborns. Gene microarrays were applied to study gene expression in umbilical cord blood cell (UCBC) from parasite-exposed (Para-POS) and non-exposed (Para-NEG) neonates. UCBC were activated with antigens of helminth (Onchocerca volvulus), amoeba (Entamoeba histolytica) or allergens of mite (Dermatophagoides farinae). When UCBC from Para-POS and Para-NEG newborns were exposed to helminth antigens or allergens consistent differences occurred in the expression of genes encoding for MHC class I and II alleles, signal transducers of activation and transcription (STATs), cytokines, chemokines, immunoglobulin heavy and light chains, and molecules associated with immune regulation (SOCS, TLR, TGF), inflammation (TNF, CCR) and apoptosis (CASP). Expression of genes associated with innate immune responses were enhanced in Para-NEG, while in Para-POS, the expression of MHC class II and STAT genes was reduced. Within functional gene networks for cellular growth, proliferation and immune responses, Para-NEG neonates presented with significantly higher expression values than Para-POS. In Para-NEG newborns, the gene cluster and pathway analyses suggested that gene expression profiles may predispose for the development of immunological, hematological and dermatological disorders upon postnatal helminth parasite infection or allergen exposure. Thus, prenatal parasite contact will sensitize without generating aberrant inflammatory immune responses, and increased pro-inflammatory but decreased regulatory gene expression profiles will be present in those neonates lacking prenatal parasite antigen encounter.

Effects of in vitro exposure of Echinococcus multilocularis metacestodes to cytostatic drugs on in vivo growth and proliferation of the parasite.

The cytostatic drugs Vincristine (VCR), Navelbine (NAV), and Methotrexate (MTX) were evaluated for their growth inhibitory potential against metacestodes of Echinococcus multilocularis (Em) by in vitro and in vivo assays. In vitro cultures of E. multilocularis were exposed to IC 90, IC 80, and IC 5 concentrations of VCR, NAV, or MTX for 1 week, then parasite tissue cultures were kept for 1 week without drug exposure in vitro, and thereafter, metacestode tissues were injected intra-peritoneally into Meriones unguiculatus. Metacestode growth was monitored for several months post-infection (p.i.) by body weight control, magnetic resonance imaging (MRI), and autopsy at 5 months p.i. Weight monitoring of infected M. unguiculatus did not provide conclusive evidence for Em-metacestode growth, while MRI could detect growing Em-metacestode in the MTX-treated group at 8 weeks (p.i.), whereas metacestodes exposed to VCR and NAV were at 17 weeks (p.i.) detectable. MRI disclosed progressive and massive growth of Em-metacestode in the VCR- and MTX-exposed groups, while the NAV-pretreated Em-metacestodes' volume did not exceed 4 cm(3). At autopsy, Em-metacestodes of less than 4 cm(3) were found in infected M. unguiculatus, which was not detected by MRI. In summary, the cytostatic drugs Methotrexate, Navelbine, and Vincristine--as applied in the present work--did not show parasitocidal or clear parasitostatic effects on metacestodes of E. multilocularis. While parasite growth in vivo was inhibited in NAV- and VCR-pretreated Em-metacestodes, MTX pretreatment seemed to enhance parasite proliferation. Magnetic resonance imaging appears suitable to monitor in vivo the effects of drugs on growth progression and regression only of larger Em-metacestode tissues.

Cytokine and chemokine responses in adults, newborns and children exposed to Entamoeba histolytica/dispar, Onchocerca volvulus and Plasmodium falciparum.

Cytokine and chemokine response profiles were studied in newborns, 10-yr-old children and post partum mothers. All study groups were repeatedly exposed to Entamoeba histolytica, Onchocerca volvulus and Plasmodium falciparum infections as indicated by their Immunoglobulin (IgG) responses to parasite-specific antigens. As key indicators for regulatory and pro-inflammatory cytokine and chemokine responses, Interferon (IFN)gamma and regulatory IL-10 were investigated, along with the chemokines MIP-1 alpha/CCL3, MIP-1 beta/CCL4, MDC/CCL22 and TARC/CCL17. Entamoeba histolytica antigens (EhAg) strongly activated pro-inflammatory MIP-1 alpha/CCL3 and MIP-1 beta/CCL4 responses of similar magnitude in mothers, children and neonates alike. Plasmodium falciparum antigens (PfAg) enhanced MIP-1 alpha/CCL3, MIP-1 beta/CCL4 and MDC/CCL22 production in neonates, but did not trigger these chemokines in mothers or 10-yr-old children. Onchocerca volvulus antigens (OvAg) activated IFN-gamma and TARC/CCL17 production in mothers but not in neonates and children. Crude IL-10 production [i.e., without subtracting spontaneous cellular release (baseline)] was highest in mothers and somewhat lower in neonates, while the lowest IL-10 amounts of all were released by peripheral blood mononuclear cells from 10-yr-old children. In summary, strong inflammatory chemokine responses to plasmodia and ameba antigens in newborns and 10-yr-old children suggest that adequately balanced immune regulatory mechanisms may not have developed yet in these age groups and that repeated exposure to parasite infections and immune maturation during childhood is required to generate similar cytokine and chemokine profiles as in adults.

Coinfections with Schistosoma haematobium, Necator americanus, and Entamoeba histolytica/Entamoeba dispar in children: chemokine and cytokine responses and changes after antiparasite treatment.

The effect of polyparasite infections on cytokine and chemokine responses as well as the effect of antiparasite treatment was studied in children without parasite infection (the G0 group), in children singly infected with Schistosoma haematobium (the G1 group), and in children multiply infected with S. haematobium/Schistosoma mansoni, Entamoeba histolytica/Entamoeba dispar, and Necator americanus (the G3+ group). Linear regression analysis disclosed a significant risk for coinfection with hookworm and Schistosoma species. Polyparasite infections detected in 23% of children before treatment were present in 5% at 15 months after treatment. Chemokine responses to S. mansoni adult worm antigen (SmAg) diminished after treatment for macrophage inflammatory chemokine (MIP)-1alpha/chemokine (C-C motif) ligand (CCL)-3 (among G3+ children, by a factor of 200 [95% confidence interval {CI}, 33-1111]) and for MIP-1beta/CCL-4 (among G3+ children, by a factor of 26 [95% CI, 6-117]) but were enhanced for thymus- and activation-regulated chemokine/CCL-17 (among G3+ children, by a factor of 10 [95% CI, 3-32]) (P < .001 for all). In response to E. histolytica antigen, interleukin (IL)-13 levels increased after treatment among G1 children by a factor of 138 (95% CI, 12-1569) and among G3+ children by a factor of 21 (95% CI, 7-64) (P < .001 for both). Cellular production of interferon (IFN)-gamma in response to SmAg decreased 4 weeks after treatment among G3+ children, whereas T helper cell type 2 (Th2) IL-13 production was enhanced among G1 and G3+ children. In summary, polyparasite infections with S. haematobium/S. mansoni, E. histolytica/E. dispar, and N. americanus generated prominent proinflammatory cytokine and chemokine responses, and, after antihelminth treatment, the inflammatory chemokine response lessened as the Th2 responsiveness in coinfected children increased.

Echinococcus multilocularis: inflammatory and regulatory chemokine responses in patients with progressive, stable and cured alveolar echinococcosis.

The progressive growth of Echinococcus multilocularis metacestodes and their tissue infiltration will cause organ malfunction and finally failure. In few patients, E. multilocularis metacestode proliferation will spontaneously regress, but little is known about the determinants which may restrain metacestode survival and growth. In this study, chemokine responses were investigated in E. multilocularis patients at different states of infection, i.e. with progressive, stable and cured alveolar echinococcosis (AE). Characteristic chemokine profiles and changes in their production were observed in AE patients and infection-free controls when their peripheral blood cells were cultured with E. multilocularis antigens. The production of CC and CXC chemokines which associate with inflammation (MIP-1 alpha/CCL3, MIP-1 beta/CCL4, RANTES/CCL5 and GRO-alpha/CXCL1) was constitutively larger in AE patients than in controls; and the elevated chemokine releases were equal in patients with progressive, stable or cured AE. Cluster analyses identified three distinct chemokine response profiles; chemokines were enhanced, depressed or produced in similar quantities in AE patients and controls. A disparate cellular responsiveness was observed in AE patients to viable E. multilocularis vesicles; cluster 1 (GRO-alpha/CXCL1, MCP-3/CCL7, MCP-4/CCL13, TARC/CCL17, LARC/CCL20) and cluster 2 chemokines (PARC/CCL18, MDC/CCL22, MIG/CXCL9) were clearly diminished, while cluster 3 chemokines (MIP-1 alpha/CCL3, MIP-1 beta/CCL4, RANTES/CCL5) augmented. The increased production of inflammatory chemokines in patients even with cured AE could be induced by residual E. multilocularis metacestode lesions which continuously stimulate production of inflammatory chemokines. E. multilocularis metacestodes also suppressed cellular chemokine production in AE patients, and this may constitute an immune escape mechanism which reduces inflammatory host responses, prevents tissue destruction and organ damage, but may also facilitate parasite persistence.