本文關(guān)鍵詞：B群鏈球菌42kD蛋白提取及其免疫學(xué)效果的初步探討　出處：《北京生物制品研究所》2005年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： GBS 結(jié)合疫苗 蛋白 免疫 主動保護(hù) 被動保護(hù) 交叉保護(hù)

【摘要】：B群鏈球菌(Group B Streptococcus)簡稱GBS,是引起新生兒肺炎、敗血癥和腦膜炎的主要病原菌。其多糖疫苗通常只產(chǎn)生較低的免疫活性,且多糖抗原在人體內(nèi)易受降解,易導(dǎo)致免疫耐受等特點使得多糖疫苗的廣泛應(yīng)用具有一定的局限性。GBS外源蛋白(如:破傷風(fēng)類毒素)結(jié)合疫苗雖然克服了B群鏈球菌莢膜多糖(CPS)疫苗的許多不足,但仍未解決血清型限制性的問題,而且單一載體蛋白不能對CPS提供足夠的載體效應(yīng),增加載體蛋白的量所帶來的毒性問題以及制備過程的復(fù)雜性也不容忽視。故現(xiàn)在尋求一種以GBS菌體免疫原性蛋白為基礎(chǔ)的疫苗來解決上述問題。 本實驗以一步層析法從GBS Ⅲ型菌32325株中提取42KD菌體蛋白,回收率為8%,等電點為6.6,純度為100%,并初步鑒定為糖蛋白。它既可表達(dá)在細(xì)菌表面,又可分泌到菌體之外。以42KD蛋白不同劑量和針次免疫NIH成年小鼠,間接ELISA法檢測小鼠血清IgG抗體滴度。結(jié)果顯示:不同劑量免疫均能誘導(dǎo)小鼠產(chǎn)生相應(yīng)IgG抗體,其效價最高可達(dá)1:24576,說明42KD蛋白具有很好的免疫原性。選擇最佳免疫條件免疫小鼠,然后腹腔攻擊GBSⅢ型32325菌株,觀察主動免疫和被動免疫保護(hù)效果。結(jié)果顯示:試驗組成年小鼠的免疫保護(hù)指數(shù)為100,乳鼠的免疫保護(hù)指數(shù)為40,表明試驗組較陰性對照組耐受活菌攻擊量分別大100倍和40倍。用1個LD_(50)和10個LD_(50)劑量菌液攻擊試驗組成年小鼠后存活率均可達(dá)100%,陰性對照組分別為50%和37.5%;在被動免疫保護(hù)性試驗中,用1個乳鼠的LD_(50)劑量攻擊,試驗組乳鼠存活率可達(dá)100%,而陰性對照組為50%,試驗組存活率顯著高于陰性對照組。這些結(jié)果表明42KD蛋白對成年小鼠和乳鼠均誘導(dǎo)保護(hù)免疫。不同劑量免疫保護(hù)試驗結(jié)果說明:在一定范圍內(nèi),免疫劑量與血清IgG抗體應(yīng)答水平呈正相關(guān);小鼠血清IgG抗體滴度與保護(hù)力正相關(guān)。用肺炎鏈球菌Pn6B:CMCC 31492株和Pn19F:CMCC 31699株作交叉保護(hù)性試驗,結(jié)果顯示,42KD蛋白對肺炎鏈球菌不具有交叉保護(hù)作用。
[Abstract]:Group B streptococcus group B Streptococcus, referred to as GBS, is the cause of neonatal pneumonia. The main pathogen of septicemia and meningitis. The polysaccharide vaccine usually produces only low immune activity and the polysaccharide antigen is easily degraded in human body. It is easy to lead to immune tolerance and so on, which makes the wide application of polysaccharide vaccine have certain limitations. GBS exogenous protein (such as tetanus toxoid) conjugate vaccine has overcome group B streptococcus capsule polysaccharide (CPS). Many of the shortcomings of the vaccine. However, the problem of serotype restriction has not been solved, and the single carrier protein can not provide enough carrier effect to CPS. The toxicity caused by increasing the amount of carrier protein and the complexity of the preparation process can not be ignored. Therefore, a vaccine based on the immunogenicity protein of GBS cell is now sought to solve the above problems. In this experiment, 42KD bacterial protein was extracted from 32325 strains of GBS 鈪，

本文編號：1406539