Biological variation in Trichinella species and genotypes

Antiparasitic Activity of Enterocin M and Durancin-like from Beneficial Enterococci in Mice Experimentally Infected with Trichinella spiralis

Beneficial/probiotic strains protect the host from pathogens by competitive displacement and production of antibacterial substances, i.e., bacteriocins. The antiparasitic potential of bacteriocins/enterocins and their producing strains in experimental murine trichinellosis were tested as a new therapeutic strategy. Enterocin M and Durancin-like and their producers Enterococcus faecium CCM8558 and Enterococcus durans ED26E/7 were administered daily to mice that were challenged with Trichinella spiralis. Our study confirmed the antiparasitic effect of enterocins/enterococci, which reduced the number of adults in the intestine (Enterocin M-43.8%, E. faecium CCM8558-54.5%, Durancin-like-16.4%, E. durans ED26E/7-35.7%), suppressed the Trichinella reproductive capacity ex vivo (Enterocin M-61%, E. faecium CCM8558-74%, Durancin-like-38%, E. durans ED26E/7-66%), and reduced the number of muscle larvae (Enterocin M-39.6%, E. faecium CCM8558-55.7%, Durancin-like-15%, E. durans ED26E/7-36.3%). The direct effect of enterocins on Trichinella fecundity was documented by an in vitro test in which Durancin-like showed a comparable reducing effect to Enterocin M (40-60%) in contrast to the ex vivo test. The reducing activity of T.spiralis infection induced by Enterocin M was comparable to its strain E. faecium CCM8558; Durancin-like showed lower antiparasitic activity than its producer E. durans ED26E/7.

Trichinella britovi recombinant proteins produced in Pichia pastoris expression system for specific IgG antibody detection in the sera of mice and pigs infected with Trichinella spp

Trichinellosis, a disease caused by infection with Trichinella spp, poses an economic problem in the animal sector and a recurrent health problem for humans. Discovering the new diagnostic tests may be achieved by identification and production of species- and stage-specific recombinant proteins of Trichinella genus which are recognized by the host antibodies after infection. In this study the T. britovi proteins identified earlier in excretory-secretory (ES) products: CTRL, ES21 and HSP20, were cloned and produced using a eukaryotic Pichia pastoris system. Their immunodiagnostic properties were verified by measuring the abundance of specific IgG antibodies in sera from mice and pigs experimentally infected with T. britovi or T. spiralis. The rTbCTRL and the rTbES21 proteins were more effectively produced and stable than rTbHSP20. The most sensitive protein for serodiagnostic purposes occurred to be CTRL; anti-rTbCTRL IgG level increased at 41 days post infection (dpi) in pigs infected with T. britovi and 45 dpi for those infected with T. spiralis. The rTbES21 protein was the most specific for the T. britovi species, as no antibody titers were observed in pigs infected with T. spiralis. Following the multiple-antigen strategy, the combination of rTbCTRL + rTbES21 was applied in ELISA, but no significant difference in IgG level was detected in the tested conditions.

Reprint of: Comparison between Trichinella patagoniensis and Trichinella spiralis infection in BALB/c mice

In Argentina, trichinellosis is an endemic disease acquired mainly through consumption of raw pork infected with nematodes larvae from the Trichinella genus. For years, the only species involved in outbreaks in humans and pig foci in Argentina was Trichinella spiralis. In 2008 the presence of a new Trichinella taxon from a cougar (Puma concolor) was detected and recorded in the province of Rio Negro, Argentina, and the finding was established as a new species in 2012: Trichinella patagoniensis. To the best of our knowledge, there is no information available on the intestinal phase and antibody response in a susceptible host during T. patagoniensis infection. Therefore, our research has been designed to study experimental infection with T. patagoniensis compared to infection with T. spiralis in BALB/c mice. One hundred and twenty eight BALB/c mice were divided into two groups and individuals in each group were infected per os with 500 larvae of T. patagoniensis or 500 larvae of T. spiralis, respectively. After that, they were euthanized on different days. Adult worm recovery from small intestines and artificial digestion of each carcass was performed. Histopathology of small intestines was performed using hematoxylin-eosin staining. Systemic cytokines and antibody kinetics were evaluated. Intestinal adult worm recovery of T. patagoniensis and T. spiralis took place until day 17 and 25, respectively. Systemic IFN-γ, IL-10, and TNF showed significant variations in T. patagoniensis infected mice. Seroconversion was detected in animals as from 15 days post-infection (pi) for both T. patagoniensis and T. spiralis, reaching the highest OD value at 42 days pi. Similar microscopic lesions were observed in the small intestine from mice infected with the same dose of T. spiralis and T. patagoniensis. Our findings contribute new information regarding the intestinal phase and the antibody kinetics of T. patagoniensis in BALB/c mice.

Comparison between Trichinella patagoniensis and Trichinella spiralis infection in BALB/c mice

In Argentina, trichinellosis is an endemic disease acquired mainly through consumption of raw pork infected with nematodes larvae from the Trichinella genus. For years, the only species involved in outbreaks in humans and pig foci in Argentina was Trichinella spiralis. In 2008 the presence of a new Trichinella taxon from a cougar (Puma concolor) was detected and recorded in the province of Rio Negro, Argentina, and the finding was established as a new species in 2012: Trichinella patagoniensis. To the best of our knowledge, there is no information available on the intestinal phase and antibody response in a susceptible host during T. patagoniensis infection. Therefore, our research has been designed to study experimental infection with T. patagoniensis compared to infection with T. spiralis in BALB/c mice. One hundred and twenty eight BALB/c mice were divided into two groups and individuals in each group were infected per os with 500 larvae of T. patagoniensis or 500 larvae of T. spiralis, respectively. After that, they were euthanized on different days. Adult worm recovery from small intestines and artificial digestion of each carcass was performed. Histopathology of small intestines was performed using hematoxylin-eosin staining. Systemic cytokines and antibody kinetics were evaluated. Intestinal adult worm recovery of T. patagoniensis and T. spiralis took place until day 17 and 25, respectively. Systemic IFN-γ, IL-10, and TNF showed significant variations in T. patagoniensis infected mice. Seroconversion was detected in animals as from 15 days post-infection (pi) for both T. patagoniensis and T. spiralis, reaching the highest OD value at 42 days pi. Similar microscopic lesions were observed in the small intestine from mice infected with the same dose of T. spiralis and T. patagoniensis. Our findings contribute new information regarding the intestinal phase and the antibody kinetics of T. patagoniensis in BALB/c mice.

Comparative analysis of excretory-secretory products of muscle larvae of three isolates of Trichinella pseudospiralis by the iTRAQ method

Trichinella pseudospiralis is a non-encapsulated intracellular parasitic nematode that can possess a strong ability to modulate the host immune response. Here, we compared the differentially expressed proteins of excretory-secretory (ES) products in three isolates of T. pseudospiralis muscle larvae (ML) [from Russia (RUS), United States of America (USA) and Australia (AUS)] using isobaric tags for relative and absolute quantification (iTRAQ)-based technology. A total of 2591 nonredundant proteins were identified, of which 65 (146), 72 (98) and 43 (103) significantly upregulated (downregulated) differentially expressed proteins were detected among pairwise comparisons (T4RUS vs T4USA, T4AUS vs T4USA and T4RUS vs T4AUS). In addition, GO annotation, KEGG and STRING analyses were carried out on the screened differentially altered proteins. The main biological processes involved included carbohydrate metabolic processes, DNA metabolic processes, cellular protein modification processes and homeostatic processes. The majority of KEGG pathways were found to be related to the metabolic pathways, lysosome pathway and protein processing in endoplasmic reticulum. Moreover, all ES protein expression levels involved in the lysosome pathway were significantly higher in the T4USA isolate than in the other two isolates. We also found differences in the expression of some important immunoregulatory proteins, such as protein disulfide-isomerase, thioredoxin protein and deoxyribonuclease-2-alpha, between different isolates of T. pseudospiralis ML. Flow cytometry was used to detect the increase in the CD4+/CD8 + T-cell ratio in pig peripheral blood and to verify the effect of T. pseudospiralis on the Th1/Th2 polarization of the host. Quantitative real-time PCR analysis also confirmed that the changes in the transcriptional level of genes were consistent with those at the proteomic level. These findings reveal the possible role of significantly differentially expressed proteins in ES products of the different isolates of T. pseudospiralis in antagonizing and participating in the regulation of the host immune response and maintaining a stable growth environment.

Effect of probiotic bacteria on phagocytosis and respiratory burst activity of blood polymorphonuclear leukocytes (PMNL) in mice infected with Trichinella spiralis

This study focusses on the effect of probiotic (bacteriocinogenic) strains on parasite infection and innate immunity - phagocytosis and oxidative burst of blood monocytes and polymorphonuclear leukocytes (PMNL) in mice infected with Trichinella spiralis. Bacteriocinogenic and probiotic strains of different origin (Enterococcus faecium AL41=CCM8558, Enterococcus durans ED26E/7, Lactobacillus fermentum AD1=CCM7421, Lactobacillus plantarum 17L/1) were administered daily in dose of 10⁹CFU/ml in 100μl and mice were infected with 400 larvae of T. spiralis on 7th day of treatment. Phagocytic activity of blood leukocytes was inhibited at week 3 and 4 post infection (p.i.), i.e. in the time of massive muscle invasion with larvae T. spiralis. Administration of bacterial strains to mice prior to T. spiralis infection elevated and prolonged phagocytic activity of blood leukocytes and their ingestion capability from week 1 to 3 of the infection and the phagocytosis was inhibited only at week 4 p.i. The highest stimulative effect on phagocytosis was induced by strains E. durans ED26E/7, L. fermentum AD1=CCM7421, and L. plantarum 17L/1. The percentage of cells with respiratory burst and their enzymatic activity was increased after T. spiralis infection with the exception of week 3 p.i. In contrast, in all mice treated with bacterial strains the enzymatic stimulation was observed after the infection, with the highest intensity caused by strains E. durans ED26E/7, L. fermentum AD1=CCM7421 and L. plantarum 17L/1. The administration of probiotic strains stimulated phagocytosis and respiratory burst of blood PMNL that could contribute to a decreased larval migration and a destruction of muscle larvae and then reduced parasite burden in the host. The protective effect against T. spiralis infection was induced by all strains, but the highest reduction was recorded by E. faecium AL41=CCM8558.