Amebiasis and mucosal IgA antibody against the entamoeba histolytica adherence lectin in Bangladeshi children

Amebiasis is the third leading parasitic cause of death worldwide, and it i s not known whether immunity is acquired from a previous infection. An inve stigation was done to determine whether protection from intestinal infectio n correlated with mucosal or systemic antibody responses to the Entamoeba h istolytica GalNAc adherence lectin. E. histolytica colonization was present in 0% (0/64) of children with and 13.4% (33/246) of children without stool IgA anti-GalNAc lectin antibodies (P = .001). Children with stool IgA lect in-specific antibodies at the beginning of the study had 64% fewer new E. h istolytica infections by 5 months (3/42 IgA(+) vs. 47/227 IgA(-); P = .03). A stool antilectin IgA response was detected near the time of resolution o f infection in 67% (12/18) of closely monitored new infections. It was conc luded that a mucosal IgA antilectin antibody response is associated with im mune protection against E. histolytica colonization. The demonstration of n aturally acquired immunity offers hope for a vaccine to prevent amebiasis.