7月10日，P NATL ACAD SCI USA雜志報(bào)道了一項(xiàng)通過(guò)表達(dá)單鏈抗體阻斷惡性瘧原蟲孢子在蚊蟲體內(nèi)產(chǎn)生的研究,。這為惡性瘧疾防治的研究開辟了一條新路,。
在給予惡性瘧原蟲時(shí)，表達(dá)m1C3, m4B7,，或m2A10單鏈抗體（scFvs）的斯氏按蚊（Anopheles stephensic）與對(duì)照組相比,，感染水平顯著較低。
這些scFvs源于分別特異性針對(duì)寄生蟲殼多糖酶：25 kDa蛋白和環(huán)子蛋白所產(chǎn)生的抗體,。利用位點(diǎn)特異性重組,，合成m2A10與m1C3或m4B7組合抗體的轉(zhuǎn)基因序列被插入先前研究過(guò)的蚊子染色體的"停靠"位點(diǎn),。
研究者在四個(gè)不同的基因組位置檢測(cè)了這些轉(zhuǎn)基因的表達(dá)水平,，并對(duì)一個(gè)允許這些轉(zhuǎn)基因發(fā)生組織和性別特異性表達(dá)的?？空军c(diǎn)，進(jìn)一步加以研究,。結(jié)果僅發(fā)現(xiàn)一個(gè)顯著的健康性效應(yīng)：在染色體?？课稽c(diǎn)帶有轉(zhuǎn)基因的成體雄性斯氏按蚊顯示出遲發(fā)性生存率的降低。
在四分之三的實(shí)驗(yàn)中,，給予帶有m4B7/m2A10的蚊子惡性瘧原蟲,，很少或根本沒有瘧原蟲孢子（感染人類的寄生蟲階段）的產(chǎn)生。在發(fā)育相關(guān)時(shí)間段誘導(dǎo)m1C3/m2A10同時(shí)表達(dá),，則無(wú)法在施加了惡性瘧原蟲的m4B7/m2A10蚊子體內(nèi)檢測(cè)到瘧原蟲孢子,。
這些研究支持的結(jié)論是，一個(gè)單拷貝的雙抗體基因的表達(dá)可以完全抑制瘧原蟲的發(fā)展,，而不損害蚊子的存活,。這為惡性瘧疾的防治提供了新的思路。（生物谷bioon.com）
doi:10.1016/j.cell.2011.10.017
PMC:
PMID:
Transgenic Anopheles stephensi coexpressing single-chain antibodies resist Plasmodium falciparum development
Alison T. Isaacsa,b,Nijole Jasinskieneb,Mikhail Tretiakovb,Isabelle Thieryc,Agnès Zettorc,Catherine Bourgouinc,d, andAnthony A. Jamesa,b,1
Anopheles stephensi mosquitoes expressing m1C3, m4B7, or m2A10 single-chain antibodies (scFvs) have significantly lower levels of infection compared to controls when challenged with Plasmodium falciparum, a human malaria pathogen. These scFvs are derived from antibodies specific to a parasite chitinase, the 25 kDa protein and the circumsporozoite protein, respectively. Transgenes comprising m2A10 in combination with either m1C3 or m4B7 were inserted into previously-characterized mosquito chromosomal “docking” sites using site-specific recombination. Transgene expression was evaluated at four different genomic locations and a docking site that permitted tissue- and sex-specific expression was researched further. Fitness studies of docking site and dual scFv transgene strains detected only one significant fitness cost: adult docking-site males displayed a late-onset reduction in survival. The m4B7/m2A10 mosquitoes challenged with P. falciparum had few or no sporozoites, the parasite stage infective to humans, in three of four experiments. No sporozoites were detected in m1C3/m2A10 mosquitoes in challenge experiments when both genes were induced at developmentally relevant times. These studies support the conclusion that expression of a single copy of a dual scFv transgene can completely inhibit parasite development without imposing a fitness cost on the mosquito.
