Department of Microbiology, University of Mississippi Medical Center, Jackson, MS 39216, USA.
J Ocul Pharmacol Ther. 2010 Dec;26(6):571-7. doi: 10.1089/jop.2010.0077. Epub 2010 Oct 29.
To determine whether immunization with pneumolysin (PLY) protects against pneumococcal endophthalmitis.
New Zealand white rabbits were immunized with a mutant form of PLY that retains only 1% of its cytolytic activity until serum IgG titers were ≥51,200. For a negative control, rabbits were immunized with phosphate-buffered saline (mock). Each vitreous was injected with 10(2) colony-forming units of a clinical endophthalmitis isolate of Streptococcus pneumoniae. Severity of endophthalmitis was graded by slit lamp examination at 24 and 48 h postinfection (PI). Serial dilutions of vitreous were plated for bacterial colony-forming units quantitation, eyes were extracted for histology, and a whole blood survival assay was performed.
Immunized rabbits had a significantly lower mean slit lamp examination score at 24 and 48 h PI when compared to mock immunized rabbits (P ≤ 0.002). There was not a significant difference in bacterial load in the vitreous at 24 or 48 h PI. Histological sections showed that retinas of mock immunized rabbits appeared to be destroyed, whereas those of PLY immunized rabbits remained largely intact. Damage spread to the aqueous humor, stroma, and conjunctiva of mock immunized rabbits by 48 h PI. Minimal damage was observed in the vitreous of PLY immunized rabbits and did not spread to other parts of the eye. Whole blood from immunized rabbits inhibited the growth of bacteria better than whole blood from mock immunized rabbits.
Immunization with PLY helps protect the eye from damage caused by pneumococcal endophthalmitis.
确定肺炎球菌溶血素（PLY）免疫是否能预防肺炎球菌性眼内炎。
用仅保留 1%细胞溶解活性的 PLY 突变体对新西兰白兔进行免疫，直至血清 IgG 滴度≥51200。作为阴性对照，用磷酸盐缓冲盐水（模拟）对兔子进行免疫。每个玻璃体注射 10（2）个临床眼内炎分离株肺炎链球菌的菌落形成单位。感染后 24 和 48 小时（PI）通过裂隙灯检查对眼内炎的严重程度进行分级。对玻璃体进行连续稀释以进行细菌菌落形成单位定量，提取眼睛进行组织学检查，并进行全血存活测定。
与模拟免疫的兔子相比，免疫的兔子在感染后 24 和 48 小时 PI 的平均裂隙灯检查评分显著降低（P≤0.002）。在 24 或 48 小时 PI 时，玻璃体中的细菌负荷没有显著差异。组织学切片显示，模拟免疫的兔子的视网膜似乎被破坏，而 PLY 免疫的兔子的视网膜基本完整。损伤在 48 小时 PI 时扩散到模拟免疫的兔子的房水、基质和结膜。在 PLY 免疫的兔子的玻璃体中观察到最小的损伤，并且没有扩散到眼睛的其他部位。免疫兔子的全血比模拟免疫兔子的全血更能抑制细菌的生长。
PLY 免疫有助于保护眼睛免受肺炎球菌性眼内炎引起的损害。
