骆驼重链抗体的出现及演化机制

The emergence and evolution mechanism of camel heavy chain antibody

经典的IgG抗体由2条相同的重链(H)和2条相同的轻链(L)组成,由H链和L链共同构成抗体-抗原结合区的规则由缺失轻链和CH1区的重链抗体(heavy chain antibody,hcAb)打破。重链抗体以其分子量小,稳定性高,免疫原性弱,组织穿透力强,可以结合一些常规抗体无法接近的抗原表位等特点,显示出其与常规抗体相比在抗体-抗原结合及免疫防御中的优势。了解重链抗体是何时以及如何演化出现的对于理解这种特殊类型的抗体在机体免疫保护中的作用具有重要意义。

The classical antibodies are composed of two heavy chains （H） and two light chains （L）. However, the rules which composed of the antigen-combining sites with H chain and L chain in conventional IgG antibodies were violated by the discovery of natural devoid of light chains IgG antibodies in camelids. Camel heavy chain antibodies （HCAbs） possess many interesting properties, such as potent enzyme inhibitors, the recognition of unique conformational epitopes with the dominant involvement of its long CDR3, highly soluble in aqueous environments, high stability, weak immunogenicity and smaller size, which making hcAbs promising molecules for biotechnological applications. It was worthwhile to elucidate how hcAbs response to antigen induction, and what the role of hcAbs in immune protection in camelids.