摘要
目的 研究经不同免疫途径 ,O1 5 7:H7大肠杆菌外膜蛋白 (OMP)对小鼠接受致死剂量该菌攻击后的免疫保护作用。方法 用外膜蛋白分别通过鼻腔、口腔和皮下途径对雌性BALB/c小鼠免疫 3次 ,采用ELISA测定血、阴道冲洗液和粪便内抗体水平 ;用Western 印迹方法分析诱导小鼠产生抗外膜蛋白特异性抗体的抗原 ;用致死剂量O1 5 7:H7大肠杆菌活菌经口腔攻毒 ,观察记录动物的发病与死亡情况 ;观察受染动物器官病理变化。结果 ELISA结果表明 ,经鼻腔与口腔免疫 ,能有效诱导抗外膜蛋白IgA和IgG免疫应答 ,鼻腔免疫更为有效。经皮下免疫仅能诱导血中产生高水平的特异性IgG抗体。攻毒后 ,鼻腔和口腔免疫组小鼠存活率明显高于对照组 (86 7%比 4 0 % ,P <0 0 1和 73 3%比 4 0 % ,P <0 0 5 ) ,鼻腔免疫组更高 (86 7%比 73 3% ,P <0 0 5 )。而皮下免疫组存活率甚至低于对照组 (1 3 3%比 4 0 % ,P <0 0 5 )。结论 O1 5 7:H7大肠杆菌外膜蛋白对实验小鼠的该菌株致死剂量攻击有较强的保护作用。鼻腔免疫途径为O1 5
Objective To evaluate the protective efficacy against a lethal dose of E coli O157:H7 after intranasal, oral and subcutaneous immunization with the outer membrane protein(OMP) extracted from the whole cell of E coli O157:H7 Methods Female BALB/C mice were immunized three times(on days 0,7 and 14) with OMP and CT or Complete Frund adjuvant On the 21st day after the last immunization, serum, fecal extracts and vaginal washes were collected for the detection of antigen specific antibody responses by ELISA before the oral challenge with E coli O157: H7 933 And the antigens that induced the specific antibody responses were analysed by Western blotting Then, the mice were orally challenged with 0 3 ml 4 25×10 10 /ml live E coli O157: H7, and the mortality was recorded On the 7th day after the challenge, the mice were sacrificed and the heart, liver, lung, kidney, small intestine and colon were collected Then the histology lesions were observed by light microscopy Results In ELISA, both intranasal and oral immunization, with CT as a mucosal adjuvant, induced strong anti OMP IgA responses in serum, fecal extract and vaginal washes, and anti OMP IgG responses in serum However, the intranasal immunization was much more effective to induce specific IgA and IgG responses than the oral immunization In contrast to mucosal immunization, subcutaneous immunization only induced high levels of specific IgG antibodies in serum, and did not effectively promote IgA immune response The results of the protective efficacy after challenge showed that both intranasal and oral immunizations with OMP provided significant protection (86 7% to 40%, P <0 01 and 73 3% to 40%, P <0 05)against a lethal dose of E coli O157:H7 challenge, and intranasal immunization possessed a better protective ability (86 7% to 73 3%, P <0 05) In contrast, the mice immunized subcutaneously were not protected They were died more early after oral challenge Furthermore, the histopathological features of the kidney, colon and other organs also appeared to be well correlated with immunization route In comparison with the mice immunized subcutaneously and those in control group, the severity of the histopathological lesions in the tissues of the mice immunized intranasally was minimal Conclusion These results suggested that the intranasal immunization should be the best choice of vaccine development against E coli O157:H7
出处
《中华医学杂志》
CAS
CSCD
北大核心
2004年第1期58-62,共5页
National Medical Journal of China
