Inhibition of <i>Entamoeba histolytica</i> proteolytic activity by human salivary IgA antibodies

Guerrero-Manríquez, Gloria G.; Sánchez-Ibarra, Francisco; Ávila, Eva E.

doi:10.1111/j.1699-0463.1998.tb00263.x

Cited by 10 publications

(5 citation statements)

References 23 publications

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“…Indirect evidence comes from one study showing that newborns living in an endemic area were protected against the amoebic intestinal infection during breastfeeding (33). Direct evidence comes from studies showing that sIgA isolated from salivas of patients with intestinal amoebiasis diminished in vitro the adhesion of virulent trophozoites to epithelial cells avoiding their destruction (34), purified sIgA reduce proteolytic activity of parasite extracts (35), and that the raising of this type of antibodies by immunization is associated with protection in experimental models against intestinal colonization (36) and, interestingly, against ALA (37). However, recent field studies in children suffering amoebiasis by the Petri group in Dhaka, Bangladesh, have provided the best evidence of association between the raising of sIgA anti‐Gal lectin and development of acquired immunity against the intestinal infection with E. histolytica .…”

Section: Secretory Immune Response In the Infection By Entamoeba Histmentioning

confidence: 99%

The role of the secretory immune response in the infection by Entamoeba histolytica

Carrero

Cervantes-Rebolledo

Aguilar-Díaz

et al. 2007

Parasite Immunology

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Intestinal infection with the protozoan parasite Entamoeba histolytica elicits a local immune response with rising of specific secretory IgA (sIgA) antibodies detectable in several compartments associated to mucosa. Anti-amoebic sIgA antibodies have been reported in faeces, saliva, bile and breast milk from dysenteric patients and research trying to elucidate their role in protection has recently intensified. IgA antibodies inhibit the in vitro adherence of E. histolytica trophozoites to epithelial cell monolayers by recognizing several membrane antigens, including the galactose-binding lectin (Gal-lectin), main surface molecule involved in adherence, and the serine and cystein-rich proteins, all of them potential vaccine candidates. In fact, the presence of sIgA anti-Gal lectin in faeces of patients recovered from amoebic liver abscess (ALA) was associated with immunity to E. dispar. Moreover, the combined nasal and intraperitoneal vaccination of C3H/HeJ mice with native and recombinant Gal-lectin protected mice against an intracecal challenge with virulent E. histolytica trophozoites, protection that seemed to be associated with the induction of specific intestinal sIgA antibodies. Therefore, the stimulation of intestinal secretory response by mucosal delivery of amoebic antigens has been positioned as a promising strategy for inducing protection against human amoebiasis.

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Section: Secretory Immune Response In the Infection By Entamoeba Histmentioning

confidence: 99%

The role of the secretory immune response in the infection by Entamoeba histolytica

Carrero

Cervantes-Rebolledo

Aguilar-Díaz

et al. 2007

Parasite Immunology

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“…46 IgA also inhibits amoebic proteolytic activities in vitro. 47 In asymptomatic carriers, the recognition of the E. histolytica 115-kDa surface protein by human sIgA has been reported. 48 In fact, it has been postulated for use in the vaccination with the E. histolytica Gal/Gal lectin, a molecule implicated in mediate parasite adherence to the colonic surface.…”

Section: Amoebicidal Effect Of Human Milk Is Due To the Protein Fractmentioning

confidence: 99%

Amoebicidal Activity of Milk, Apo-lactoferrin, sIgA and Lysozyme

León-Sicairos¹,

López-Soto²,

Reyes-López³

et al. 2006

Clinical Medicine & Research

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Entamoeba histolytica is a pathogenic, parasitic protozoan that can infect the large intestine and cause amoebiasis, an illness responsible for at least 100,000 deaths annually worldwide. The capacity of human milk to kill amoebas 6,15 and the amoebicidal action of secretory immunoglobulin type A (sIgA) 16 have been reported. However, it is unknown which other components of milk are amoebicides. As milk contains several microbicidal components, we fractionated milk and tested each fraction against trophozoites in axenic cultures to describe any amoebicidal effects of other components of human and bovine milk such as lactoferrin, lysozyme and sIgA. We also sought to identify any combined effect among these molecules. Objectives: To identify amoebicidal components in human milk and the effect of iron on the amoebicidal activity. Original ResearchDesign: Investigation in axenic cultures of Entamoeba histolytica trophozoites.Methods: Amoebas were treated with 5%-20% of human, bovine and swine milk, with 10% of human milk fractions (i.e., casein, proteins except casein and fat) or with 1 mg/ml of human milk apo-lactoferrin, human secretory immunoglobulin type A (sIgA) and chicken egg-white lysozyme (i.e., purified proteins). Milk proteins were detected using immunoblot. Confocal microscopy was used to define the interaction of milk proteins (100 µM each) and amoebas. Experiments were done at least three times in triplicate, and mean and standard deviations were calculated.Results: Human and bovine milk were amoebicidal showing a concentration-dependent effect. The amoebicidal effect was increased in the absence of iron. Milk protein fractions, with the exception of casein, were the components responsible for the amoebicidal activity found. Apo-lactoferrin, sIgA and lysozyme were identified in the amoebicidal milk protein fraction. Apo-lactoferrin showed the major amoebicidal effect. These proteins, either alone or in combination, showed a killing effect on the trophozoites.They bound to the amoebic membrane causing cell rounding, lipid disruption and damage. Conclusions:Milk proteins such as apo-lactoferrin, sIgA and lysozyme are able to kill Entamoeba histolytica trophozoites.This study confirms the importance of feeding breast milk to newborns.

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“…Amoebic CPs are potent immunogens, as they induce high levels of antibodies in infected humans and animals. Thus, up to 84% of human salivary samples from patients with intestinal amoebiasis recognized a purified 70 kDa CP on Western blot, and the specific secretory IgA antibodies inhibited the proteolytic activity of E. histolytica extracts [ 124 ]. Based on this finding, CPs have been proposed as targets for the development of new treatments and vaccines.…”

Section: Entamoeba Histolytica Cysteine Proteases: Repertoir...mentioning

confidence: 99%

Extracellular Cysteine Proteases of Key Intestinal Protozoan Pathogens—Factors Linked to Virulence and Pathogenicity

Argüello-García

Carrero

Ortega-Pierres

2023

IJMS

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Intestinal diseases caused by protistan parasites of the genera Giardia (giardiasis), Entamoeba (amoebiasis), Cryptosporidium (cryptosporidiosis) and Blastocystis (blastocystosis) represent a major burden in human and animal populations worldwide due to the severity of diarrhea and/or inflammation in susceptible hosts. These pathogens interact with epithelial cells, promoting increased paracellular permeability and enterocyte cell death (mainly apoptosis), which precede physiological and immunological disorders. Some cell-surface-anchored and molecules secreted from these parasites function as virulence markers, of which peptide hydrolases, particularly cysteine proteases (CPs), are abundant and have versatile lytic activities. Upon secretion, CPs can affect host tissues and immune responses beyond the site of parasite colonization, thereby increasing the pathogens’ virulence. The four intestinal protists considered here are known to secrete predominantly clan A (C1- and C2-type) CPs, some of which have been characterized. CPs of Giardia duodenalis (e.g., Giardipain-1) and Entamoeba histolytica (EhCPs 1-6 and EhCP112) degrade mucin and villin, cause damage to intercellular junction proteins, induce apoptosis in epithelial cells and degrade immunoglobulins, cytokines and defensins. In Cryptosporidium, five Cryptopains are encoded in its genome, but only Cryptopains 4 and 5 are likely secreted. In Blastocystis sp., a legumain-activated CP, called Blastopain-1, and legumain itself have been detected in the extracellular medium, and the former has similar adverse effects on epithelial integrity and enterocyte survival. Due to their different functions, these enzymes could represent novel drug targets. Indeed, some promising results with CP inhibitors, such as vinyl sulfones (K11777 and WRR605), the garlic derivative, allicin, and purified amoebic CPs have been obtained in experimental models, suggesting that these enzymes might be useful drug targets.

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Inhibition of Entamoeba histolytica proteolytic activity by human salivary IgA antibodies

Cited by 10 publications

References 23 publications

The role of the secretory immune response in the infection by Entamoeba histolytica

The role of the secretory immune response in the infection by Entamoeba histolytica

Amoebicidal Activity of Milk, Apo-lactoferrin, sIgA and Lysozyme

Extracellular Cysteine Proteases of Key Intestinal Protozoan Pathogens—Factors Linked to Virulence and Pathogenicity

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