Immunology of Entamoeba histolytica in Human and Experimental Hosts. In: Talwar GP, editor. Progress in Vaccinology. New York: Springer; 1989. pp. 227-51. [DOI: 10.1007/978-1-4612-3508-8_22]

Immunoreactivity of Entamoeba histolytica antigens with sera from amoebic patients

Immune sera from 15 patients with cured amoebic liver abscess were used to recognise the antigens of Entamoeba histolytica (HMI) by immunoblotting. The amoebic proteins most frequently recognised by sera from patients with cured amoebic liver abscess had molecular masses of 8, 13, 18, 22, 29, 38, 45, 67 and 94 kDa. Six plasma membrane-associated amoebic proteins of molecular mass 29, 38, 45-67 complex, 85 and 94 kDa were strongly recognised by such sera. Two plasma membrane-associated antigens of 108 and 129 kDa were not recognised by any sera. None of the crude or plasma membrane-associated antigens were recognised by sera from five patients of idiopathic ulcerative colitis, five patients of persistent giardiasis and five normal healthy subjects. Identification of such antigens, especially plasma membrane-associated antigens may pave a way to develop specific diagnostic and immunoprotective agents.

Recognition of 29 kDa surface-associated adhesive molecule of Entamoeba histolytica by monoclonal antibodies

Monoclonal antibodies have been developed and used as specific probe to locate and identify a 29-kDa molecule of axenic Entamoeba histolytica trophozoites. Monoclonal antibody produced by clone C8 (MoAb C8) strongly agglutinated the amoebic trophozoites. The immunofluorescence of live E. histolytica trophozoites and surface fluorescence of acetone-fixed trophozoites by MoAb C8 indicated existence of a 29-kDa molecule on surface-associated plasma membrane of E. histolytica. The monoclonal antibody belonged to IgG1 isotype. The prior treatment of E. histolytica trophozoites with MoAb C8 resulted in significant (P less than 0.01) reduction in adherence of amoebic trophozoites to cultured Chinese Hamster Ovary cells and significant (P less than 0.01) reduction in cytotoxicity to cultured Baby Hamster Kidney cells. Pretreatment of amoebic trophozoites with MoAb C8 prior to cultivation in TPS-1 medium resulted in significant (P less than 0.01) reduction in growth of the parasite. Thus, the data suggested that the surface-exposed 29-kDa molecule may be one of the receptors involved in E. histolytica host cell interactions and may possibly modulate amoebic disease processes.