Adaptive immune responses to Acanthamoeba cysts.
Acanthamoeba cysts are not eliminated from the corneas of human subjects or experimentally infected animals. The persistence of Acanthamoeba cysts in the cornea indicates that either the cysts escape immunological elimination or are not recognized by the host's immunological elements. The aim of this study was to determine the immunogenicity and antigenicity of the Acanthamoeba cyst. Mice were immunized intraperitoneally and serum anti-Acanthamoeba IgG was measured by ELISA. Lymphoproliferative assay and delayed type hypersensitivity (DTH) responses to Acanthamoeba castellanii cyst and trophozoite antigens were used to determine the cell mediated immune responses against Acanthamoeba cysts. A. castellanii cysts were both immunogenic and antigenic, producing anti-Acanthamoeba serum IgG, T lymphocyte proliferation, and delayed type hypersensitivity responses. These results indicate that Acanthamoeba cysts are recognized by the immune system. The persistence of the organism in the human cornea means that these adaptive immune responses fail to kill Acanthamoeba cysts.
McClellan
Kathy
K
Department of Ophthalmology, University of Sydney, GPO BOX 4337, Sydney, NSW 2121, Australia.
Howard
Kevin
K
Mayhew
Elizabeth
E
Niederkorn
Jerry
J
Alizadeh
Hassan
H
D000048:Acanthamoeba / Q000276:immunology*; D015823:Acanthamoeba Keratitis / Q000276:immunology*; D000818:Animals; D000913:Antibodies, Protozoan / Q000096:biosynthesis; D000953:Antigens, Protozoan / Q000276:immunology; D018929:Cell Culture Techniques; D002455:Cell Division / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006968:Hypersensitivity, Delayed / Q000276:immunology; D007111:Immunity, Cellular; D007074:Immunoglobulin G / Q000096:biosynthesis; D051379:Mice; D008810:Mice, Inbred C57BL; D015800:Protozoan Proteins / Q000032:analysis; D013601:T-Lymphocytes / Q000276:immunology
D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D007074:Immunoglobulin G; D015800:Protozoan Proteins