Dendritic Cells in the Gut: Interaction with Intestinal Helminths

The mucosal environment in mammals is highly tolerogenic; however, after exposure to pathogens or danger signals, it is able to shift towards an inflammatory response. Dendritic cells (DCs) orchestrate immune responses and are highly responsible, through the secretion of cytokines and expression of surface markers, for the outcome of such immune response. In particular, the DC subsets found in the intestine have specialized functions and interact with different immune as well as nonimmune cells. Intestinal helminths primarily induce Th2 responses where DCs have an important yet not completely understood role. In addition, this cross-talk results in the induction of regulatory T cells (T regs) as a result of the homeostatic mucosal environment. This review highlights the importance of studying the particular relation “helminth-DC-milieu” in view of the significance that each of these factors plays. Elucidating the mechanisms that trigger Th2 responses may provide the understanding of how we might modulate inflammatory processes

Are Basophils Important Mediators for Helminth-Induced Th2 Immune Responses? A Debate

Helminth parasites induce Th2 immune responses. Immunological mechanisms leading to Th2 induction are mainly dependent on IL-4. However, early source of IL-4 has not been precisely identified. Noticeably, basophils seem to be important mediators for inducing and maintaining the Th2 response probably because they secrete IL-4 and exert functions similar to APCs. Nevertheless, recent experimental evidence points that DCs could be also significant participants during this process. The involvement of basophils during memory responses is also discussed

Echinococcosis in Mexico — A Story Worth Sharing

At the beginning of the XXI millennium, while working at a general hospital in Mexico City, a young lady arrived with a previous diagnosis of liver amebiasis given six years earlier. Different treatments in various clinical settings were provided. In the hospital, the first approach was an ultrasound study and unexpectedly an Echinococcus granulosus cyst was clearly identified. The patient received adequate treatment and accepted to participate as the index case in an epidemiological survey performed in her community. Inhabitants, dogs, cattle, pigs, and sheep were studied; cysts in humans, pigs, and sheep were searched by ultrasound and dogs by coproantigens, livestock, and dogs were negative for larval or adult stages respectively. The use of ultrasound allowed the detection of two cases (overall prevalence 0.95). DNA of the patient’s cyst recovered by surgery was purified, amplified, sequenced, and multiple alignments were performed and analyzed, identifying to Echinococcus ortleppi. Subsequently, in a population genetics study focused to evaluate the presence and genetic variability of the intestinal tapeworm in dogs and of cystic echinococcosis in livestock in central areas from Mexico, Echinococcus canadensis G7 was identified and was found only in pigs. Based on a genetic network analysis, the following deductions were made: 1) E. canadensis G7 in Mexico is very diverse and was probably introduced from abroad several times from different sources and from different countries; 2) G7 haplotypes grouped in the North American wildlife cluster are placed far from Mexican isolates, thus they might be ruled out as sources of introduction to Mexico; and 3) the species status for G7, formally named E. canadensis, is still controversial, because biologically different strains (G6 to G10) are currently unified, though ecological and genetic data appear to indicate otherwise

Proliferative Response of Hamster CD4+ T Cells after Different Mitogenic Stimulation

The measurement of effector cells involved in immune responses is an important parameter in various  fields of lymphocyte research using the Syrian Golden hamster as the experimental model. The aim of  the present study was to identify the percentage of peripheral hamster CD4+ cells that undergo proliferation  and the number of cell divisions induced by four different mitogenic compounds: phorbol-myristate  acetate plus ionomycin (PMA/ionomycin), concanavalin A (Con A), phytohaemagglutinin (PHA) and the  superantigen Staphylococcal enterotoxin B (SEB). The proliferative response was investigated by the use of  the cross-reactive mouse anti-CD4 antibody (clone H129.9) and analyzed by flow cytometry using the dye  carboxyfluorescein diacetate succinimydil ester (CFSE). PMA/ionomycin induced the highest proliferative  response of CD4+ cells. Interestingly, the down-regulation in the CD4 expression described after PMA/  ionomycin activation both in human and in mouse lymphocytes was not seen in hamster cells. Stimulation  with SEB and with Con A also induced up to 6 to 7 proliferation cycles in cells, whereas PHA induced the  lowest proliferation. These results provide useful tools for the study of CD4+ cells in the hamster model.

Immunolocalization of TSOL18 and TSOL45-1A, the successful protective peptides against porcine cysticercosis, in Taenia solium oncospheres

Taenia solium life cycle includes humans as definitive hosts and pigs as intermediate hosts. One of the measures to stop the life cycle of this parasite is by vaccination of pigs. In experiments performed in pigs with TSOL18 and TSOL45-1A, two recombinant T. solium proteins, 99.5% and 97.0% protection was induced, respectively. The purpose of this paper was to localize these antigens in all stages of the parasite (adult worms, oncospheres and cysticerci) by immunofluorescence, with the use of antibodies against TSOL18 and TSOL45-1A that were obtained from the pigs used in the vaccination experiment. Results show that TSOL18 and TSOL45-1A are expressed on the surface of T. solium oncospheres and not in tapeworms or cysticerci, indicating that they are stage-specific antigens. This, therefore, might explain the high level of protection these antigens induce against pig cysticercosis

Development of Taenia pisiformis in golden hamster (Mesocricetus auratus)

The life cycle of Taenia pisiformis includes canines as definitive hosts and rabbits as intermediate hosts. Golden hamster (Mesocricetus auratus) is a rodent that has been successfully used as experimental model of Taenia solium taeniosis. In the present study we describe the course of T. pisiformis infection in experimentally infected golden hamsters. Ten females, treated with methyl-prednisolone acetate were infected with three T. pisiformis cysticerci each one excised from one rabbit. Proglottids released in faeces and adults recovered during necropsy showed that all animals were infected. Eggs obtained from the hamsters' tapeworms, were assessed for viability using trypan blue or propidium iodide stains. Afterwards, some rabbits were inoculated with eggs, necropsy was performed after seven weeks and viable cysticerci were obtained. Our results demonstrate that the experimental model of adult Taenia pisiformis in golden hamster can replace the use of canines in order to study this parasite and to provide eggs and adult tapeworms to be used in different types of experiments

Tomografía computarizada experimental en el cerdo

Se describe una técnica original para la obtenci6n de imágenes tomografías simples y contrastadas de encéfalo de cerdos parasitados con la fase larvaria de la Taenia solium

Use of Oxfendazole to Control Porcine Cysticercosis in a High-Endemic Area of Mozambique

A randomized controlled field trial to evaluate the effectiveness of a single oral dose of 30 mg/kg of oxfendazole (OFZ) treatment for control of porcine cysticercosis was conducted in 4 rural villages of Angónia district, north-western Mozambique. Two hundred and sixteen piglets aged 4 months were selected and assigned randomly to OFZ treatment or control groups. Fifty-four piglets were treated at 4 months of age (T1), while another 54 piglets were treated at 9 months of age (T2) and these were matched with 108 control pigs from the same litters and raised under the same conditions. Baseline data were collected on the prevalence of porcine cysticercosis using antigen ELISA (Ag-ELISA), as well as knowledge and practices related to Taenia solium transmission based on questionnaire interviews and observations. All animals were followed and re-tested for porcine cysticercosis by Ag-ELISA at 9 and 12 months of age when the study was terminated. Overall prevalence at baseline was 5.1% with no significant difference between groups. At the end of the study, 66.7% of the controls were found positive, whereas 21.4% of the T1 and 9.1% of the T2 pigs were positive, respectively. Incidence rates of porcine cysticercosis were lower in treated pigs as compared to controls. Necropsy of 30 randomly selected animals revealed that viable cysts were present in none (0/8) of T2 pigs, 12.5% (1/8) of T1 pigs and 42.8% (6/14) of control pigs. There was a significant reduction in the risk of T. solium cysticercosis if pigs were treated with OFZ either at 4 months (OR = 0.14; 95% CI: 0.05–0.36) or at 9 months of age (OR = 0.05; 95% CI: 0.02–0.16). Strategic treatment of pigs in endemic areas should be further explored as a means to control T. solium cysticercosis/taeniosis

Estimating the Non-Monetary Burden of Neurocysticercosis in Mexico

Neurocysticercosis (NCC) is a major public health problem caused by the larvae of the parasite Taenia solium. The condition occurs when humans ingest eggs of the pork tapeworm Taenia solium, which then develop into larvae in the central nervous system. The disease is predominantly found and considered important in Latin American, Asian, and African countries and is associated with a large social and economic burden. Very few studies have been conducted to evaluate the burden of NCC and there are no estimates from Mexico. We estimated the disability adjusted life years (DALYs) lost due to NCC in Mexico incorporating morbidity and mortality due to NCC-associated epilepsy, and morbidity due to NCC-associated severe chronic headaches. NCC-associated epilepsy and severe chronic headaches were estimated to cause a loss of approximately 0.25 healthy year of life per 1,000 persons annually in Mexico. This is the first estimate of DALYs associated with NCC in Mexico. However, this value is likely to be underestimated since only the clinical manifestations of epilepsy and severe chronic headaches were included