科研動(dòng)態(tài)

納米抗體（nanobody，Nb）是在駱駝血清中發(fā)現(xiàn)的一種新型抗體，具有相對(duì)分子質(zhì)量小、穩(wěn)定性高、親和力高、組織滲透性強(qiáng)以及可識(shí)別抗原縫隙表位、進(jìn)一步改造和表達(dá)等特點(diǎn)。Nb篩選技術(shù)分為噬菌體展示、酵母雙雜交、mRNA展示以及高通量測(cè)序和質(zhì)譜分析等4種，它們都能夠快速篩選到特異性Nb。對(duì)具有高度親和力的Nb，多種表達(dá)系統(tǒng)均可以實(shí)現(xiàn)高效表達(dá)。其中：原核表達(dá)最常用，其操作相對(duì)簡(jiǎn)單、產(chǎn)量大、生產(chǎn)成本低，但要去除表達(dá)出的重組蛋白內(nèi)毒素；酵母表達(dá)可以直接收集培養(yǎng)基上清純化，雜蛋白含量少，但可能存在過(guò)度糖基化問(wèn)題；植物宿主可以大量表達(dá)Nb，但基因操作過(guò)程繁瑣，且分離純化Nb相對(duì)困難；哺乳動(dòng)物細(xì)胞生產(chǎn)抗體也是較常用的方式，但生產(chǎn)成本較高。針對(duì)每一種篩選方法和表達(dá)系統(tǒng)目前沒(méi)有統(tǒng)一的評(píng)價(jià)標(biāo)準(zhǔn)，在選擇時(shí)，應(yīng)以實(shí)驗(yàn)室條件為基礎(chǔ)，充分了解篩選對(duì)象的結(jié)構(gòu)、功能和用途，根據(jù)不同目的選用。本文對(duì)Nb結(jié)構(gòu)特點(diǎn)、篩選及表達(dá)以及在動(dòng)物疫病防治中的應(yīng)用展開(kāi)論述，可為相關(guān)領(lǐng)域研究提供技術(shù)支持。

Research Progress on the Screening and Expression of Nanobody

Nanobody（Nb），a new antibody found in camel serum，is characterized by small molecular weight，high stability，high affinity，strong tissue permeability，and recognition of antigen gap epitopes，further modification and expression. Nb screening technology includes phage display，yeast double hybridization，mRNA display and high-throughput sequencing and mass spectrometry analysis，all of which could rapidly screen specific Nb. For the Nb with high affinity，many expression systems could be used to realize an effectively expression. Specifically，prokaryotic expression is mostly used due to its simple operation，mass production and low production cost，but the output of recombinant protein endotoxin should be removed；yeast expression could be used to directly collect purification of medium supernatant，with small content of miscellaneous protein，but excessive glycosylation may be available；host plants could express Nb in large quantity，but the process of gene operation is complicated and it is difficult to isolate and purify Nb；antibody produced by cells of mammals is also usually used，but its production cost is high. No uniform evaluation standard has been developed for all the above methods and expression systems till now. A decision should be made based on laboratory conditions and according to corresponding purpose provided that the structure，function and usage of the object to be screened should be well understood. In the paper，the structure，screening and expression of Nb as well as its application in the prevention and control of animal diseases were discussed，which might technically support the study in related fields.

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