ABSTRACT
The presence of secretory Immunoglobulin anti-Entamoeba histolytica antibodies has been demonstrated in the bile of intracecally immunized rats, in human milk and in colostrum. Invasive amebiasis nearly always elicits prompt systemic humoral immune responses. Specific circulating antibodies are usually detectable one week after the onset of symptoms in experimental animals and humans. Immediate hypersensitivity skin reactions have been described using antigenic material obtained from Entamoeba histolytica grown in monoxenic or axenic medium. The humoral response that follows the invasion by Entamoeba histolytica apparently neither cures nor prevents subsequent reinfection, which can occur in the presence of high antibody titers. Passive immunoprophylaxis against amebiasis is of little practical interest for a disease with these clinical and epidemiological characteristics. Dogs passively immunized with whole blood from immune donors contracted infection less frequently than control animals, a state of immunity that lasted for 2 months.
