肺炎链球菌重组自溶酶（Re-LytA）滴鼻免疫小鼠的实验研究  

Study on intranasal immunizations with recombinated-pneumococcal autolysin （Re-LytA） in mice

作　　者：甘慧泉[1] 鲜墨[2] 袁竹青[3] 吴忠道[3] 李明[1] 周茂华[1] 

机构地区：[1]广东省人民医院病理医学部检验科,广州510080 [2]广州市呼吸疾病研究所 [3]中山大学中山医学院病原生物学教研室,广州510080

出　　处：《中华微生物学和免疫学杂志》2008年第7期629-633,共5页Chinese Journal of Microbiology and Immunology

摘　　要：目的评价重组肺炎链球菌（Streptococcus pneumoniae，Sp）自溶酶（autolysin，LytA）滴鼻免疫诱导小鼠抗Sp感染的保护性效果。方法用亲和层析的方法纯化出重组SpLytA蛋白，以CpG作佐剂，对小鼠进行滴鼻免疫（A组）。对照组（B组）用无菌盐水滴鼻；多糖疫苗组（C组）用23价多糖疫苗肌肉注射。于末次免疫后2周，用Sp分别以滴鼻和腹腔注射两种方式进行攻击感染。攻击之前采集血清和鼻咽灌洗液等样品，采用ELISA测试其抗体水平。滴鼻攻击后4d，采集小鼠鼻咽灌洗液和肺灌洗液，进行Sp细菌计数；腹腔注射攻击后7d内观察各组小鼠死亡情况。结果B组未检测到LytA抗体和多糖抗体，C组多糖抗体阳性；A组LytA抗体（包括IgG、IgA、sIgA）均明显高于对照组，差异具有统计学意义（P〈0．05）。腹腔注射攻击后，A、C组小鼠的存活率明显高于B组（P〈0．05），A组和C组之间没有明显区别（P〉0．05）。滴鼻攻击后，A组鼻咽部灌洗液sp细菌计数明显低于B组和C组（P〈0．05）。结论Re-LytA滴鼻免疫可诱导实验小鼠产生一定的抵抗Sp感染的保护性免疫力，这种保护性的免疫力可能与sIgA相关。Objective To evaluate the protective effectiveness of intranasal immunizations with recombinated-pneumococcal autolysin（ Re-LytA）, which protects mice against local and systemic Streptococcus pneumoniae（Sp） infection. Methods Testing group （group A）： CpG as an adjuvant, the mice were intranasally immunized with purified Re-LytA, obtained by affinity chromatograph. The negative control group（ group B ） were intranasally immunized with sterile saline. And the positive control group （group C ） were received 23-valent polysaccharide commercial vaccine through intramuscular injection. All the samples were collected 2 weeks post the last immunization. The levels of antibody was determined by ELISA. Then the mice were challenged intraperitoneally and intranasally with Sp, respectively. The infection and coloniza- tion was followed by monitoring colony-forming units of Sp in the blood, homogenized lung, and nasopharyn- geal lavage fluid 4 days post intranasal immunization. The mice were observed daily to note the livability of each group. Results The level of the LytA antibody （IgG, IgA, sIgA） in group A were higher than that in group B and C （P〈0.05）. Neither the LytA nor polysaccharide antibody could be detected in group B. Polysaccharide antibody could be detected in group C. After challenged intraperitoneally there was no significant difference in survival rates between group A and group C （P〉0.05）, which was significant higher than that in group B （P〈0.05）. After challenged intranasally, compared with the group A, the geometric mean colony-forming units washed from the nasopharyngeal lavage fluid of the group B and group C were significantly higher （P〈0.05）. Conclusion Intranasal immunizations with Re-LytA can protect mice against local and systemic pneumococcal infection, and the protective immunity may be related to sIgA.

关 键 词：肺炎链球菌 自溶酶 滴鼻免疫 

分 类 号：R392[医药卫生—免疫学]