Leher H, Kinoshita K, Alizadeh H, Zaragoza F L, He Y, Niederkorn J
Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas 75235-9057, USA.
Invest Ophthalmol Vis Sci. 1998 Nov;39(12):2337-43.
To determine whether oral immunization mitigates ongoing Acanthamoeba castellanii corneal infections in pigs.
Pigs were orally immunized with aqueous Acanthamoeba antigen mixed with cholera toxin (Ac-CT) or with saline, before or after ocular infection with A. castellanii. Mucosal secretions (i.e., tears and enteric wash) were tested for Acanthamoeba-specific IgA by enzyme-linked immunosorbent assay. Enteric washes were used as a source of IgA in assays measuring the binding of trophozoites to Chinese hamster corneal epithelial (CHCE) cells.
Pigs immunized with Ac-CT before ocular challenge with A. castellanii had significant anti-Acanthamoeba IgA antibody titers in their tears and enteric washes and were protected against ocular infection. Enteric washes from orally immunized pigs inhibited trophozoite binding to CHCE cells in vitro by more than 75%. By contrast, pigs immunized after corneal infections had been established displayed keratitis of the same severity and duration as that in control pigs. However, 80% of the orally immunized animals were resistant to rechallenge with Acanthamoeba-laden contact lenses, whereas none of the control animals was resistant.
Oral immunization with Ac-CT protects against Acanthamoeba keratitis when administered before corneal challenge. However, delaying oral immunization until after corneal disease is established fails to mitigate keratitis. The appearance of parasite-specific tear IgA correlates with protection and may act by preventing the parasite's binding to the corneal epithelium.
确定口服免疫是否能减轻猪体内正在进行的卡氏棘阿米巴角膜感染。
在猪眼部感染卡氏棘阿米巴之前或之后，用与霍乱毒素混合的棘阿米巴水性抗原（Ac-CT）或生理盐水对猪进行口服免疫。通过酶联免疫吸附测定法检测黏膜分泌物（即眼泪和肠道灌洗液）中的棘阿米巴特异性IgA。在测量滋养体与中国仓鼠角膜上皮（CHCE）细胞结合的试验中，肠道灌洗液用作IgA的来源。
在眼部受到卡氏棘阿米巴攻击之前用Ac-CT免疫的猪，其眼泪和肠道灌洗液中具有显著的抗棘阿米巴IgA抗体滴度，并受到眼部感染的保护。口服免疫猪的肠道灌洗液在体外可抑制滋养体与CHCE细胞的结合达75%以上。相比之下，在角膜感染已经形成后进行免疫的猪，其角膜炎的严重程度和持续时间与对照猪相同。然而，80%的口服免疫动物对载有棘阿米巴的隐形眼镜再次攻击具有抗性，而对照动物均无抗性。
在角膜攻击之前给予Ac-CT口服免疫可预防棘阿米巴角膜炎。然而，将口服免疫推迟到角膜疾病形成后并不能减轻角膜炎。寄生虫特异性泪液IgA的出现与保护作用相关，可能通过阻止寄生虫与角膜上皮结合而起作用。
