Role of mucosal secretory immunity in the development of an amebiasis vaccine.

Invasive colonic infection by the enteric protozoan Entamoeba histolytica elicits a mucosal anti-amebic IgA antibody response. The E. histolytica galactose-inhibitable adherence protein (GIAP) mediates parasite binding to colonic mucins and epithelial cells. Anti-GIAP secretory IgA antibodies are found during invasive amebiasis and can be elicited by immunization of rats with the native protein. Entamoeba histolytica contains potent IgA degradative activities due to its cysteine-specific proteases. Research is needed to further understand the role of secretory antibodies in natural or vaccine-induced immunity to E. histolytica.