STUDY: Protective immunity to amebiasis: new insights and new challenges.
JOURNAL: J Infect Dis 2001 Aug 15;184(4):504-6
AUTHORS: Stanley Jr SL.
ABSTRACT: Amebiasis, infection with the protozoan parasite Entamoeba histolytica, is the third leading cause of death from parasitic diseases. Despite its importance, we know little about protective immunity to amebiasis. Now, studies from a cohort of children in Bangladesh have provided some critical insights into immunity to intestinal amebiasis. Children with mucosal IgA antibodies to the amebic adherence lectin were found to be resistant to reinfection with E. histolytica. However, immunity was short-lived, and approximately 20% of children in the cohort had a second episode of E. histolytica infection during the study period. Theses findings indicate that immunity to amebiasis can develop in some children after intestinal infection, but protective immunity may be transient, and its importance in preventing disease remains to be established.
COMMENTARY: The immune system apparently can manufacture antibodies to lectins made by microbes (and used to attach to membranes of the gut.) What is not addressed in the article is the potential of anti-adherence therapy using blocking sugars (the Amoebic lectin is galactose (group and n-acetyl galactosamine (group A) specific, so the use of pectins and connective tissue mucopolysaccharides (such as chondroitin) may be of benefit in children recovering from parasitic infection. This may be even more significant for non-secretors, since the leck both free ABH antigens, and have lower than average levels of IgA (the antibody class of the anti-lectin antibodies).