ABSTRACT
Toll-like receptors (TLR) are involved in the recognition of numerous pathogens, including Acanthamoeba spp. Thanks to this, it is possible for immune cells to recognize microorganisms and trigger the body's innate immune response. The stimulation of TLRs also leads to the activation of specific immunity. The aim of the study was to determine the TLR2 and TLR4 gene expression in the skin of BALC/c mice infected with Acanthamoeba with AM22 strain isolated from a patient. Receptor expression was assessed by real-time polymerase chain reaction (qPCR) in the amoeba-infected host with normal (A) and reduced immunity (AS) as well as in the control host with normal immunity (C) and reduced immunity (CS). Statistical analysis of TLR2 gene expression in A and AS groups compared to C and CS groups, respectively, were statistically insignificant. In the A group, we found statistical upregulation of TLR4 gene expression at 8 dpi compared to the C group. While in AS group, TLR4 gene expression was at a similar level, such as in the CS group. Taking into account the host's immune status, the TLR4 gene expression was statistically higher in the skin of host from A group than in host from AS group at the beginning of the infection. Increased TLR4 gene expression in hosts with normal immunity infected with Acanthamoeba suggests the involvement of the studied receptor in the course of acanthamoebiasis. The above research results provide new data on the involvement of the studied receptor in the skin in the host's immune defense triggered during the Acanthamoeba infection.
ABSTRACT
Giardia, Cryptosporidium, Cyclospora, and microsporidia are gastrointestinal pathogens that can cause various disease symptoms in both animals and humans. Numerous studies worldwide have confirmed the presence of these eukaryotic pathogens in nesting and migrating wild geese, ducks, and swans. Migration spreads these zoonotic enteric pathogens to distant locations, which could have public health implications. Soils and water bodies (lakes, ponds, rivers and wetlands) in urban and suburban areas have been shown to be vulnerable to contamination by waterfowl droppings. This review addresses the epidemiology of these enteric pathogens in wild migratory bird species (Anatidae) and some consequences of their spread in the environment. To date, both zoonotic pathogens and genotypes restricted to avian hosts have been found in faecal samples from 21 anatid species worldwide. One of the routes of infection for these zoonotic gastrointestinal micropathogens is the indirect route. For example, shared water bodies (e.g., for drinking or recreational purposes) previously contaminated by birds during the migratory season may facilitate infections of humans through water. However, it is unclear how much wild waterfowl contribute to the transmission of giardiasis, cryptosporidiosis, cyclosporosis, and microsporidiosis in many regions through contaminated environmental sources. Comprehensive epidemiological surveillance based on molecular data on gastrointestinal pathogens is crucial to take measures to control infections in the future.
ABSTRACT
Giardia duodenalis is a cosmopolitan flagellate that causes giardiasis, one of the most significant gastrointestinal diseases in humans. This parasite can be a serious threat to public health because it can cause waterborne outbreaks as well as sporadic infections in humans. Invasive raccoons (Procyon lotor) may play a role in disseminating Giardia into the environment and transmitting it to humans and domestic animals because they live in high densities and deposit their faces in latrines near areas used by humans. While Giardia infections have been reported from raccoons in North America, it is unknown whether they carry G. duodenalis with zoonotic assemblage A and B, which have the potential to cause illness in humans. We collected faecal samples from 66 legally harvested raccoons in Germany and Luxembourg and examined for Giardia using molecular techniques. Using a quantitative PCR based on primers specific to Giardia genetic assemblages A and B, we detected the presence of zoonotic assemblage B in 27% (95% CI, 17.0-39.6) of all examined faecal samples from raccoons, including animals sampled in buildings. We did not detect genetic assemblage A in any of the samples. Sequences obtained from the glutamate dehydrogenase and beta-giardin gene fragments from a selection of three of the positive samples showed that raccoons carried a zoonotic G. duodenalis genotype belonging to sub-assemblage BIV, which is commonly found in humans and animals worldwide. Our results suggest that free-ranging raccoons have the potential to play an increasingly important role in the epidemiology of Giardia and pose a threat to public health in Europe and other regions where this species is common and lives in close association with humans.
Subject(s)
Giardia lamblia/genetics , Giardiasis/veterinary , Raccoons/parasitology , Zoonoses , Animals , Feces/parasitology , Female , Germany/epidemiology , Giardiasis/epidemiology , Giardiasis/parasitology , Luxembourg/epidemiology , Male , PhylogenyABSTRACT
BACKGROUND: Acanthamoeba spp. are cosmopolitan protozoans that cause infections in the brain, as well as extracerebral infections in the cornea, lungs and skin. Little is known about the mechanisms of the immunological response to these parasites in organs which are not their main biotope. Therefore, the purpose of this study was to determine the expression of TLR2 and TLR4 in the kidneys and heart of Acanthamoeba spp.-infected mice, with respect to the host's immunological status. METHODS: The mice were grouped into four groups: immunocompetent control mice; immunosuppressed control mice; immunocompetent Acanthamoeba spp.-infected mice; and immunosuppressed Acanthamoeba spp. infected mice. In the study, we used the amoebae T16 genotype which was isolated from a patient. The TLRs expressions in the kidneys and heart of mice were assessed by quantitative real-time polymerase chain reaction. Moreover, we visualized TLR2 and TLR4 proteins in the organs by immunohistochemical staining. RESULTS: In the kidneys, we observed a higher TLR2 expression in immunosuppressed mice at 24 days post-Acanthamoeba spp. infection (dpi) compared to the uninfected mice. There were no statistically significant differences in TLR4 expression in the kidneys between the immunocompetent and immunosuppressed mice, both of infected and uninfected mice. In the heart, we observed a difference in TLR2 expression in immunocompetent mice at 24 dpi compared to immunocompetent mice at 8 dpi. The immunocompetent Acanthamoeba spp.-infected mice had higher TLR4 expression at 8 dpi compared to the immunocompetent uninfected mice. CONCLUSIONS: Our results indicate that TLR2 is involved in response to Acanthamoeba spp. infection in the kidneys, whereas in the heart, both studied TLRs are involved.
Subject(s)
Acanthamoeba/physiology , Amebiasis/parasitology , Kidney/parasitology , Toll-Like Receptor 2/genetics , Toll-Like Receptor 4/genetics , Amebiasis/genetics , Amebiasis/immunology , Animals , Humans , Immunocompromised Host , Kidney/immunology , Male , Mice , Mice, Inbred BALB C , Toll-Like Receptor 2/immunology , Toll-Like Receptor 4/immunologyABSTRACT
INTRODUCTION: Toll-like receptors (TLRs) play an important role in fast activation of the immune response to a variety of pathogens, including parasites. In this study, we focused on TLR2, because this receptor is one of the best known and most frequently analysed members of the TLR family. The aim of this study was to assess the effect of Trichinella spiralis on expression of TLR2 during the intestinal stage of infection. MATERIAL AND METHODS: The experimental material consisted of isolates prepared from the intestines (jejunum and colon) of BALB/c mice infected with T. spiralis taken at 4, 8, and 16 days post infection. RESULTS: Our results based on quantitative real-time PCR showed that the mRNA level for TLR2 was statistically significantly higher in the jejuna of mice infected with T. spiralis than in this tissue of uninfected mice. In addition, the presence of TLR2 protein in the intestinal phase of trichinellosis was confirmed by a strong positive immunohistochemical reaction. CONCLUSION: Our results indicate that infection with T. spiralis changes the expression of TLR2 in the small intestine of the mouse host and suggest a contribution of these receptors to the host defence mechanisms during experimental trichinellosis.
ABSTRACT
Toll-like receptors (TLRs) play a key role in the innate immune response to numerous pathogens, including Acanthamoeba spp. The aim of this study was to determine the expression of TLR2 and TLR4 in the eyes of mice following intranasal infection with Acanthamoeba spp. in relation to the host's immunological status. Amoebae used in this study were isolated from the bronchial aspirate of a patient with acute myeloid leukemia (AML) and atypical symptoms of pneumonia. We found statistically significant differences in the expression of TLR2 and TLR4 in the eye of immunocompetent mice at 8, 16, and 24 days after Acanthamoeba spp. infection (dpi) compared to control group. Immunosuppressed mice showed significant differences in the expression of TLR2 at 16 and 24 dpi compared to uninfected animals. Our results indicate that TLR2 and TLR4 are upregulated in the eyes of mice in response to Acanthamoeba spp. We suggest that it is possible for trophozoites to migrate through the optic nerve from the brain to the eyes. The course of disseminated acanthamoebiasis may be influenced by the host's immunological status, and the observed changes in expression of TLR2 and TLR4 in the host's organs may indicate the role of these receptors in the pathomechanism of acanthamoebiasis.
Subject(s)
Amebiasis/immunology , Eye Proteins/immunology , Eye/immunology , Gene Expression Regulation/immunology , Toll-Like Receptor 2/immunology , Toll-Like Receptor 7/immunology , Acanthamoeba/immunology , Amebiasis/pathology , Animals , Eye/parasitology , Humans , Male , Mice , Mice, Inbred BALB CABSTRACT
The genus Acanthamoeba, which may cause different infections in humans, occurs widely in the environment. Lung inflammation caused by these parasites induces pulmonary pathological changes such as pulmonary necrosis, peribronchial plasma cell infiltration, moderate desquamation of alveolar cells and partial destruction of bronchial epithelial cells, and presence of numerous trophozoites and cysts among inflammatory cells. The aim of this study was to assess the influence of plant extracts from Artemisia annua L. on expression of the toll-like receptors TLR2 and TLR4 in lungs of mice with acanthamoebiasis. A. annua, which belongs to the family Asteraceae, is an annual plant that grows wild in Asia. In this study, statistically significant changes of expression of TLR2 and TLR4 were demonstrated. In the lungs of infected mice after application of extract from A. annua the expression of TLRs was observed mainly in bronchial epithelial cells, pneumocytes (to a lesser extent during the outbreak of infection), and in the course of high general TLR expression. TLR4 in particular was also visible in stromal cells of lung parenchyma. In conclusion, we confirmed that a plant extract of A. annua has a modulatory effect on components of the immune system such as TLR2 and TLR4.
Subject(s)
Acanthamoeba/physiology , Amebiasis/drug therapy , Artemisia annua/chemistry , Lung Diseases, Parasitic/drug therapy , Plant Extracts/therapeutic use , Toll-Like Receptors/metabolism , Amebiasis/metabolism , Animals , DNA, Complementary/metabolism , Immunohistochemistry , Lung/parasitology , Lung/pathology , Lung Diseases, Parasitic/metabolism , Mice , Mice, Inbred BALB C , Plant Extracts/pharmacology , RNA, Messenger/metabolism , RNA, Protozoan/genetics , RNA, Protozoan/isolation & purification , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction , Reverse Transcription , Toll-Like Receptor 2/drug effects , Toll-Like Receptor 2/genetics , Toll-Like Receptor 2/metabolism , Toll-Like Receptor 4/drug effects , Toll-Like Receptor 4/genetics , Toll-Like Receptor 4/metabolism , Toll-Like Receptors/drug effects , Toll-Like Receptors/geneticsABSTRACT
The treatment of acanthamoebiasis is a still a problem. Our previous studies showed that the application of extracts from Artemisia annua L. significantly prolonged the survival of mice infected by Acanthamoeba. This plant has medicinal properties in the treatment of human parasitic diseases. The aim of this study was to evaluate the effects of A. annua on expression of Toll-like receptors (TLRs) 2 and 4 in brain of mice with Acanthamoeba infection. Mice were infected with Acanthamoeba sp. strain Ac309 (KY203908) by intranasal inoculation without and after application of A. annua extract. The administration of extract from A. annua significantly reduced the level of expression of TLR2 and modified the level of expression of TLR4. A. annua extract is a natural substance that is well tolerated in animals and may be considered as a combination therapy in treatment of acanthamoebiasis. Our study suggested that A. annua extract may be used as an alternative therapeutic tool.
Subject(s)
Acanthamoeba/drug effects , Amebiasis/drug therapy , Artemisia annua/chemistry , Brain/metabolism , Phytotherapy , Toll-Like Receptors/drug effects , Amebiasis/metabolism , Animals , Brain/pathology , Gene Expression , Immunohistochemistry , Mice , Mice, Inbred BALB C , Plant Extracts/pharmacology , Plant Extracts/therapeutic use , RNA, Messenger/metabolism , Real-Time Polymerase Chain Reaction , Toll-Like Receptor 2/drug effects , Toll-Like Receptor 2/genetics , Toll-Like Receptor 2/metabolism , Toll-Like Receptor 4/drug effects , Toll-Like Receptor 4/genetics , Toll-Like Receptor 4/metabolism , Toll-Like Receptors/genetics , Toll-Like Receptors/metabolismABSTRACT
INTRODUCTION: Toll-like receptors (TLRs) play a key role in the rapid activation of the innate immune response to a variety of pathogens. The aim of this study was to evaluate the effect of Trichinella spiralis infection on the level of expression of the tlr4 gene in mouse intestines during the intestinal phase of experimental trichinellosis. MATERIAL AND METHODS: The experimental material consisted of the small and large intestines of BALB/c mice infected with Trichinella spiralis sampled at 4, 8, and 16 days post infection (dpi). RESULTS: A statistically significant increase was demonstrated in the tlr4 mRNA level isolated from the infected mice jejunum at 4, 8, and 16 dpi over the uninfected control. Moreover, at 4, 8, and 16 dpi in the jejunum of infected mice, a strong positive reaction for the presence of TLR4 protein compared with that of uninfected mice was observed. CONCLUSION: Infection with T. spiralis changes the expression of the tlr4 gene in the small intestine of the mouse host.
ABSTRACT
The Toll-like receptors (TLRs) of the innate immune system play an important role in the recognition of pathogens such as bacteria, viruses, fungi, and parasites. In this study, we examined the changes in the level of expression of TLR2 and TLR4 mRNA and protein in the brains of mice infected with Acanthamoeba spp. The Acanthamoeba strains were isolated from a patient with Acanthamoeba keratitis (AK) (Ac55) and Malta Lake (Ac43). In the brain isolated from mice at 2 days post-infection (dpi) with Acanthamoeba strains Ac55 and Ac43, mRNAs for TLR2 and TLR4 were significantly more strongly expressed in comparison with the uninfected mice. In Acanthamoeba-infected mice, TLR2 and TLR4 expression was detected in neurons, glial cells, and endothelial cells within the neocortex. These receptors showed more intense expression in ependymocytes of the choroid plexus of infected mice at 2 dpi. Increased levels of TLR2 and TLR4 mRNA expression in infected mice suggest the involvement of these TLRs in the recognition of Acanthamoeba spp. pathogen-associated molecular patterns (PAMPs).
Subject(s)
Acanthamoeba/immunology , Amebiasis/immunology , Brain/metabolism , Endothelial Cells/metabolism , Ependymoglial Cells/metabolism , Neurons/metabolism , Toll-Like Receptor 2/immunology , Toll-Like Receptor 4/immunology , Acanthamoeba/genetics , Acanthamoeba Keratitis/parasitology , Animals , Brain/parasitology , Mice , Mice, Inbred C57BL , RNA, Messenger/genetics , Toll-Like Receptor 2/genetics , Toll-Like Receptor 4/geneticsABSTRACT
Toll-like receptors (TLRs) play a key role in the innate immune responses to a variety of pathogens including parasites. TLRs are among the most highly conserved in the evolution of the receptor family, localized mainly on cells of the immune system and on other cells such as lung cells. The aim of this study was to determine for the first time the expression of TLR2 and TLR4 in the lung of Acanthamoeba spp. infected mice using quantitative real-time polymerase chain reaction (Q-PCR) and immunohistochemical (IHC) staining. The Acanthamoeba spp. were isolated from a patient with Acanthamoeba keratitis (AK) (strain Ac 55) and from environmental samples of water from Malta Lake (Poznan, Poland - strain Ac 43). We observed a significantly increased level of expression of TLR2 as well as TLR4 mRNA from 2 to 30 days post Acanthamoeba infection (dpi) in the lungs of mice infected with Ac55 (KP120880) and Ac43 (KP120879) strains. According to our observations, increased TLR2 and TLR4 expression in the pneumocytes, interstitial cells and epithelial cells of the bronchial tree may suggest an important role of these receptors in protective immunity against Acanthamoeba infection in the lung. Moreover, increased levels of TLR2 and TLR4 mRNA expression in infected Acanthamoeba mice may suggest the involvement of these TLRs in the recognition of this amoeba pathogen-associated molecular pattern (PAMP).
Subject(s)
Acanthamoeba/physiology , Amebiasis/metabolism , Lung Diseases, Parasitic/metabolism , Toll-Like Receptor 2/metabolism , Toll-Like Receptor 4/metabolism , Animals , Gene Expression Regulation , Humans , Immunohistochemistry , Lung/metabolism , Lung/parasitology , Lung Diseases, Parasitic/parasitology , Mice , Mice, Inbred BALB C , RNA, Messenger/metabolism , Real-Time Polymerase Chain Reaction , Toll-Like Receptor 2/genetics , Toll-Like Receptor 4/genetics , Up-RegulationABSTRACT
The treatment of acanthamoebiasis is a great problem. Most cerebral invasions end with death, and the treatment of ocular invasions is usually long-lasting and not very effective. Numerous plant extracts and substances isolated from plants, which are effective against trophozoites or cysts, have been studied in the treatment of acanthamoebiasis. However, no agents that are simultaneously effective against both developing forms of amoebae have been discovered yet. It seems that such a plant which fulfils both tasks is Artemisia annua L. Our studies showed that water, alcohol and chloroform extracts from the herb A. annua L. can be applied in general and local treatment or in combined therapy with antibiotics in the treatment of acanthamoebiasis. Extracts from this plant show not only in vitro but also in vivo effects. Studies carried out on experimental animals infected with amoebae show that the application of these extracts significantly prolongs the survival of the animals.
Subject(s)
Acanthamoeba Keratitis/drug therapy , Amoeba/drug effects , Artemisia annua/chemistry , Encephalitis/drug therapy , Plant Extracts/pharmacology , Pneumonia/drug therapy , Animals , Plant Extracts/chemistry , Plant Extracts/isolation & purificationABSTRACT
Acanthamoeba are widespread free-living amoebae which may cause granulomatous amoebic encephalitis (GAE), keratitis, skin ulcerations and disseminated tissue infection. An important diagnostic and prognostic factor for the treatment of infection is a quick and correct diagnosis of amoebae strains. The aim of our study was to develop a rapid method for detection and identification of pathogenic Acanthamoeba spp. strains from diagnostic material collected from water. In this study we analysed five amplification-based genetic markers (Aca 16S, Ac6/210, GP, JDP, Nelson) used for identification of pathogenic Acanthamoeba spp. strains isolated in water sources in Poland, Iceland and Sweden. Our results demonstrated the presence of pathogenic Acanthamoeba strains in tap water. PCR assay appeared to be a more rapid and sensitive method to detect the presence of amoebae than the limited conventional techniques. Based on our observations, we can confirm that the use of four out of five genetic markers (Aca 16S, Ac 6/210, JDP, GP, Nelson) may be helpful in identification of Acanthamoeba spp. strains, but only one Aca 16S primer pair is a highly specific marker that distinguishes between pathogenic strains of Acanthamoeba and other free-living amoeba families.
Subject(s)
Acanthamoeba/isolation & purification , Amebiasis/parasitology , Polymerase Chain Reaction/methods , Protozoan Proteins/genetics , Acanthamoeba/genetics , Animals , DNA Primers/genetics , Genetic Markers/genetics , Humans , Iceland , Poland , Sensitivity and Specificity , Sweden , Time FactorsABSTRACT
Toll-like receptors (TLRs) play a fundamental role in the rapid activation of innate immune responses to a variety of pathogen-associated molecular patterns (PAMPs). In a previous study we observed an increase in the level of expression of TLR2 and TLR4 mRNA in the jejunum and colon during experimental hymenolepidosis in rats. In this study, we performed a quantitative real-time polymerase chain reaction (qRT-PCR), Western blot analysis and immunohistochemical staining of TLR3 and TLR9 receptors during experimental hymenolepidosis in rats. The levels of mRNA and protein expression of TLR3 and TLR9 in the jejunum had increased at 16 days post Hymenolepis diminuta infection (dpi) in the case of TLR3 and at 16 and 25 dpi in the case of TLR9. In the colon the expression of TLR3 and TLR9 had increased at 16, 25 and 40 dpi. The results of the immunohistochemical reactions showed that H. diminuta infected rats (16, 25, 40 and 60 dpi) exhibited changes in TLR3 and TLR9 localization and intensity in the epithelial cells of the jejunum and colon. The changes in the level of TLR3 and TLR9 expression may confirm involvement of the innate immune system in the pathomechanism of hymenolepidosis.
Subject(s)
Hymenolepiasis/metabolism , Hymenolepis diminuta/genetics , Toll-Like Receptors/genetics , Animals , Blotting, Western , Gene Expression Regulation , Hymenolepis diminuta/metabolism , Immunohistochemistry , Intestine, Large/metabolism , Intestine, Large/parasitology , Intestine, Small/metabolism , Intestine, Small/parasitology , Male , RNA, Messenger/isolation & purification , Rats , Rats, Wistar , Real-Time Polymerase Chain Reaction , Toll-Like Receptor 3/genetics , Toll-Like Receptor 3/metabolism , Toll-Like Receptor 9/genetics , Toll-Like Receptor 9/metabolism , Toll-Like Receptors/metabolismABSTRACT
Selected fractions of ethanolic extracts obtained from leaves and roots of Eryngium planum (Apiaceae) were evaluated in vitro for amebicidal activity against Acanthamoeba castellanii. This free-living ameba is the cause of Acanthamoeba keratitis, which is a painful, vision-impairing disease of the eyes, and chronic granulomatous amebic encephalitis. Treatment is very difficult and not always effective because of encystation, which makes the amebae highly resistant to anti-amebic drugs. The search for novel natural amebicidal agents is still of current interest. Fractions of E. planum ethanolic extract from basal leaves: flavonoid fraction (Lf), flavonoid-saponin fraction (Lf-s), saponin fraction (Ls) and phenolic acids fraction (La) and from roots: saponin fraction (Rs) and phenolic acids fraction (Ra) were assayed for antiamebic activity. In the presence of the saponin fractions and phenolic acid fractions (ranging from 1-5 mg/mL), the number of the trofozoites of Acanthamoeba castellanii viable strain 309 decreased during the experimental period (0-72 h). On the other hand, the flavonoid fraction from leaves showed a stimulating activity on the amebae. Almost all fractions (except the flavonoid fraction) showed a time- and dose-dependent amebistatic activity on the trophozoites. Of the fractions tested, the phenolic acid fraction from roots at the concentration of 5 mg/L showed the amebicidal activity on the trophozoites.
Subject(s)
Acanthamoeba castellanii/drug effects , Amebicides/pharmacology , Plant Extracts/pharmacology , Acanthamoeba castellanii/growth & development , Amebicides/isolation & purification , Dose-Response Relationship, Drug , Eryngium/chemistry , Ethanol/chemistry , Flavonoids/isolation & purification , Flavonoids/pharmacology , Hydroxybenzoates/isolation & purification , Hydroxybenzoates/pharmacology , Phytotherapy , Plant Extracts/isolation & purification , Plant Leaves , Plant Roots , Plants, Medicinal , Saponins/isolation & purification , Saponins/pharmacology , Solvents/chemistry , Time FactorsABSTRACT
The glutathione S-transferases (GSTs) are a family of multifunctional enzymes involved in cellular detoxification. The aim of this study was to evaluate the effect of albendazole--drug of choice for trichinellosis--on the total activity and kinetics of cytosolic GST in the mouse intestines during experimental trichinellosis. Our results showed a statistically significant decrease in the total GST activity both in the small and large intestines of the mice infected with the nematode Trichinella spiralis (Owen, 1835) and treated with albendazole, compared with the control mice that were infected but untreated with the drug. Furthermore, albendazole administration modified the kinetics of substrate saturation of GST in the intestines of the infected mice because the drug caused changes in Michaelis constant values of this enzyme. Based on our observations, we suggest that the quaternary structure of GST from the mouse intestines is impacted by this drug during trichinellosis.
Subject(s)
Albendazole/pharmacology , Anthelmintics/pharmacology , Glutathione Transferase/metabolism , Intestines/enzymology , Trichinellosis/drug therapy , Animals , Glutathione Transferase/genetics , Intestines/drug effects , MiceABSTRACT
The glutathione S-transferases (GSTs) are a group of multifunctional enzymes, which play a critical role in cellular detoxification. Our investigations deal with the contribution of GST in the biochemical defense against Trichinella spiralis infection. The aim of this study was to examine the effect of T. spiralis infection on the total activity and kinetic properties of cytosolic GST in the intestine during the intestinal phase of experimental trichinellosis in mice. Our results showed a statistically significant increase (relative to the uninfected control) in the total GST activity both in the small and large intestines of the infected mice. Moreover, we observed changes in the kinetics of substrate saturation of GST. Trichinellosis in the small intestine caused a 12-fold decrease in the low K (m) value and a sixfold increase in the high K (m) value. In the large intestine, infection with T. spiralis caused only a fivefold increase in the low K (m) value, whereas the high K (m) value remained unchanged. We suggest that GST from the mouse small intestine could be involved in the detoxification of parasite excretory-secretory products released to the host intestine during trichinellosis and that these products influence the quaternary structure of this enzyme.