Expulsion of the gastrointestinal cestode, Hymenolepis diminuta by tolerant rats: evidence for mediation by a Th2 type immune enhanced goblet cell hyperplasia, increased mucin production and secretion

The processes underlying expulsion of Hymenolepis diminuta in rats are not known. Expression levels of mRNAs of several cytokines revealed a Th2 response that differed between worm infection levels. IL-4 protein levels decreased while IL-13 levels increased in a 50-worm infection by 30 dpi; the converse was seen with a five-worm infection. A negative correlation was found between IL-4 or IL-13 mRNA expression and worm biomass, between IL-13 protein levels and worm number or worm biomass, and between IL-4 protein levels and worm biomass in 50-worm infections. A negative correlation between IL-4 mRNA or protein expression and worm biomass was observed with five-worm infections. A strong correlation between Muc2 mRNA expression and decreased worm number or biomass in a 50-worm infection was observed. Muc2 protein, goblet cell numbers and mucin decreased in a 50-worm infection by 20 days post-infection. These changes were not seen with five-worm infections where worms are not expelled. The data show that rats infected with 50 H. diminuta mount a Th2 response leading to high levels of IL-13, increased goblet cell numbers and increased mucin2 production and release. The mucus traps the worms, which are progressively expelled from the small intestine.     

Distribution of acetylcholinesterase activity during the development of cysticercoids of Hymenolepis diminuta (Cestoda)

The distribution of acetylcholinesterase (AChE) in oncospheres and developing cysticercoids of Hymenolepis diminuta was examined. The enzyme was localized in the nervous system and in some non-nerve cells of these larvae. In oncospheres AChE was detected in hook muscles and in the binucleated medullar center that is known to enclose two neurons. At early developmental stages of the cysticercoids the enzyme was localized in the post-oncospheral hook muscles and in subtegumental muscle fibers of the cercomer. At medium and late stages of development the activity of AChE was detected in the developing nervous system and in two and, subsequently, in four populations of cells, which gradually spread over the whole internal wall of the cyst, thus forming a thin multilayer AChE-positive lining of the cyst cavity. Following withdrawal of the scolex the lining separates the parenchyma of the turned neck from the cyst tissues and remains AChE-positive during the whole life of the parasite, i.e. up to the death of the infected host. The role played by non-neural AChE associated with the cyst cavity lining is unknown, but seems to regulate both the transport of nutrients and minerals into the scolex and waste substances in the opposite direction.     

Catalysis of NADH→NADP+ transhydrogenation by adult Hymenolepis diminuta mitochondria

Hymenolepis diminuta mitochondria catalyze nonenergy-linked and energy-linked NADH→NADP⁺ transhydrogenations, with the latter driven by electron-transport dependent NADH oxidation (electron transport-driven, ETD) or ATP hydrolysis (ATP-driven, ATPD). Using submitochondrial particles, NADH→NADP⁺ transhydrogenations were characterized further. ETD and ATPD reactions were enhanced by bovine serum albumin (BSA) and were inhibited by N,N′-dicyclohexylcarbodiimide (DCCD), carbonyl cyanide 3-chlorophenylhydrazone (CCCP), carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone (FCCP), and niclosamide. The nonenergy-linked reaction was unaffected by these additives. Except for DCCD inhibition of the ATPD reaction, BSA mitigated inhibitor effects on energy-linked activities. BSA enhanced NADH oxidase (but not ATPase) activity. Although DCCD inhibited NADH oxidase and ATPase, BSA only lessened oxidase inhibition. With protonophores, an increase in NADH oxidase (but not ATPase) activity was suggested. Oxidase inhibition by rotenone was unaffected by BSA. The ATP-hydrolyzed/NADPH-formed for the ATPD reaction was almost unity. A model for H. diminuta energy-linked transhydrogenation is presented.     

Reactive oxygen intermediates from eosinophils in mice infected with Hymenolepis nana

A large number of eosinophils were recruited to the intestinal villi after infection with Hymenolepis nana . Eosinophil numbers were increased more rapidly in challenged mice than in primary infected mice. Local intestinal eosinophils from challenged mice showed more extracellular oxygen radical release, as assessed by histochemical mothods using nitro blue tetrazolium, accompanied with tissue injury and larval degradation. Intestinal eosinophils isolated from the lamina propria induced specific oxygen radical generation in response to H. nana oncosphere extract as measured by luminol-dependent chemiluminescence. This response was stronger in challenged mice than in primary infected mice. Radical generation from uninfected mice was negligible. Lipid peroxidation in the small intestine, as measured by formation of malondialdehyde, was increased during H. nana challenge infection, the peak activity coinciding with the elimination of challenge larvae. Continuous administration of a NADPH oxidase inhibitor to sensitized mice interfered with the degeneration of challenge larvae. These results suggest that intestinal eosinophils may be the major contributor to oxygen radical production in response to H. nana and that reactive oxygen species may play a part of effector molecule in the resistance to reinfection with H. nana     

The growth ofHymenolepis microstoma in intact and gonadectomized mice

Gonadectomy or sex of the host had no effect on the mean dry weight ofHymenolepis microstoma examined on day 12 postinfection (p.i.). However, on day 20 p.i. worms from intact or sham-operated male mice were significantly heavier than those recovered from the corresponding groups of female hosts. Orchiectomy of hosts lowered the average weight of these older worms, but ovariectomy had no effect.     

Prevalence of Giardia intestinalis and Hymenolepis nana in Afghan refugee population of Mianwali district,Pakistan

Background

Present study aimed to investigate prevalence of Giardia intestinalis and Hymenolepis nana in Afghan refugees visiting Central Health Unit (CHU), Kot Chandana (Mianwali, Northern Punjab) during two years period (February 2007 to December 2009).

Methods

A total of 687 stool samples were collected from different age groups of both genders. Samples were processed under sterile conditions after gross examination. Microscopic examination was done on same day along with eggs (H. nana), cyst and trophozoites (G. intestinalis) detection after staining.

Results

The prevalence of G. intestinalis was significantly higher (x2=59.54, p<0.001) than that of H. nana. Females were found more likely to be infected as compared to males (OR: 1.40, 95% CI=1.03–1.92). Prevalence of both parasites decreased with age and highest prevalence was observed in young individuals belonging to 1–15 years of age group (41.8% and 48.7% respectively for H. nana and G. intestinalis, p<0.001). Abdominal distress (OR: 1.13, 95%CI=0.83–1.53), vomiting (OR: 1.13, 95%CI=1.13–1.81) and rectal prolapse (OR: 4.26, 95%CI=1.38–13.16) were the gastro-intestinal clinical symptoms observed in G. intestinalis. Whereas, bloody diarrhea (OR: 1.56, 95%CI=1.00–2.43) and rectal prolapse (OR: 5.79, 95%CI=1.87–17.91) were associated with H. nana infections.

Conclusions

Intestinal parasitic infections are common among Afghan refugees and serious preventive measures should be implemented to promote the safety and healthy lifestyle of these people.     

Adoptive transfer of helminth antigen‐pulsed dendritic cells protects against the development of experimental colitis in mice

Infection with helminth parasites and treatment with worm extracts can suppress inflammatory disease, including colitis. Postulating that dendritic cells (DCs) participated in the suppression of inflammation and seeking to move beyond the use of helminths per se, we tested the ability of Hymenolepis diminuta antigen‐pulsed DCs to suppress colitis as a novel cell‐based immunotherapy. Bone marrow derived DCs pulsed with H. diminuta antigen (HD‐DCs), or PBS‐, BSA‐, or LPS‐DCs as controls, were transferred into wild‐type (WT), interleukin‐10 (IL‐10) knock‐out (KO), and RAG‐1 KO mice, and the impact on dinitrobenzene sulphonic acid (DNBS)‐induced colitis and splenic cytokine production assessed 72 h later. Mice receiving HD‐DCs were significantly protected from DNBS‐induced colitis and of the experimental groups only these mice displayed increased Th2 cytokines and IL‐10 production. Adoptive transfer of HD‐DCs protected neither RAG‐1 nor IL‐10 KO mice from DNBS‐colitis. Furthermore, the transfer of CD4⁺ splenocytes from recipients of HD‐DCs protected naïve mice against DNBS‐colitis, in an IL‐10 dependent manner. Thus, HD‐DCs are a novel anti‐colitic immunotherapy that can educate anti‐colitic CD4⁺ T cells: mechanistically, the anti‐colitic effect of HD‐DCs requires that the host has an adaptive immune response and the ability to mobilize IL‐10.