2012年12月6日 訊 /生物谷BIOON/ --刊登在12月4日的國(guó)際雜志mBio上的一篇研究報(bào)告中,，來(lái)自加州大學(xué)的研究者揭示了，引發(fā)萊姆病相關(guān)細(xì)菌的一些線索,，旨在幫助研究者開(kāi)發(fā)出新型的降低感染的技術(shù),。這項(xiàng)研究中，研究者揭示了白足鼠（伯氏疏螺旋體的宿主）的免疫系統(tǒng)對(duì)于不同細(xì)菌菌株可以產(chǎn)生不同的免疫反應(yīng),，這或許幫助研究者開(kāi)發(fā)抵御感染的新方法,。
萊姆病僅僅在美國(guó)被發(fā)現(xiàn)，在過(guò)去40年里,，有25,，000人患病，給社會(huì)和個(gè)人造成嚴(yán)重的經(jīng)濟(jì)負(fù)擔(dān),。本文中,，研究者試圖去理解15種不同的伯氏疏螺旋體的流行度為何不同，在萊姆病常常發(fā)生的幾個(gè)區(qū)域,，大部分的白足鼠也受到了伯氏疏螺旋體的感染,。白足鼠不像人類和正常鼠類，當(dāng)其感染伯氏疏螺旋體后,，并不會(huì)發(fā)病,。
實(shí)驗(yàn)室條件下，研究者將白足鼠暴露于伯氏疏螺旋體下，研究其被感染的過(guò)程,，所有的伯氏疏螺旋體都會(huì)感染白足鼠,，但是有一些菌株卻會(huì)設(shè)法在白足鼠多種組織中生長(zhǎng)，以變得細(xì)菌濃度加大,。結(jié)果顯示,，白足鼠的免疫反應(yīng)越強(qiáng)烈，在其組織中發(fā)現(xiàn)的細(xì)菌越少,，反之亦然,。更為重要的是，在白足鼠組織中高濃度存在的菌株也是較為流行的菌株,。
當(dāng)針對(duì)單一的伯氏疏螺旋體蛋白產(chǎn)生免疫反應(yīng)的時(shí)候,，研究者發(fā)現(xiàn)了一種復(fù)雜的相互作用，白足鼠可以對(duì)單一細(xì)菌菌株存在的不同類型的蛋白質(zhì)產(chǎn)生不同程度的反應(yīng),，這就幫助我們解釋為何在自然界中伯氏疏螺旋體會(huì)出現(xiàn)單一多樣性,。
一旦針對(duì)白足鼠的疫苗研發(fā)出來(lái)，其就可以用于暴露在免疫過(guò)的小鼠中進(jìn)行選擇性檢測(cè)了,。這項(xiàng)研究為我們了解萊姆病以及伯氏疏螺旋體的感染,，以及新型疫苗的開(kāi)發(fā)提供了新的思路和建議。（生物谷Bioon.com）
doi:10.1128/mBio.00434-12
PMC:
PMID:
Experimental Infections of the Reservoir Species Peromyscus leucopus with Diverse Strains of Borrelia burgdorferi, a Lyme Disease Agent
Elisabeth Baum, Fong Hue, and Alan G. Barbour
The rodent Peromyscus leucopus is a major natural reservoir for the Lyme disease agent Borrelia burgdorferi and a host for its vector Ixodes scapularis. At various locations in northeastern United States 10 to 15 B. burgdorferi strains coexist at different prevalences in tick populations. We asked whether representative strains of high or low prevalence differed in their infections of P. leucopus. After 5 weeks of experimental infection of groups with each of 6 isolates, distributions and burdens of bacteria in tissues were measured by quantitative PCR, and antibodies to B. burgdorferi were evaluated by immunoblotting and protein microarray. All groups of animals were infected in their joints, ears, tails, and hearts, but overall spirochete burdens were lower in animals infected with low-prevalence strains. Animals were similar regardless of the infecting isolate in their levels of antibodies to whole cells, FlaB, BmpA, and DbpB proteins, and the conserved N-terminal region of the serotype-defining OspC proteins. But there were strain-specific antibody responses to full-length OspC and to plasmid-encoded VlsE, BBK07, and BBK12 proteins. Sequencing of additional VlsE genes revealed substantial diversity within some pairs of strains but near-identical sequences within other pairs, which otherwise differed in their ospC alleles. The presence or absence of full-length bbk07 and bbk12 genes accounted for the differences in antibody responses. We propose that for B. burgdorferi, there is selection in reservoir species for (i) sequence diversity, as for OspC and VlsE, and (ii) the presence or absence of polymorphisms, as for BBK07 and BBK12.
