Antibody Fab display and selection through fusion to the pIX coat protein of filamentous phage

详细信息    查看全文

• 作者：Mark Tornetta ; Scott Baker ; Brian Whitaker ; Jin Lu ; Qiang Chen ; Eileen Pisors ; Lei Shi ; Jinquan Luo ; Raymond Sweet ; Ping Tsui
• 关键词：Phage display ; pIX ; Fab ; Antibody engineering ; Respiratory syncytia virus ; RSV
• 刊名：Journal of Immunological Methods
• 出版年：2010
• 出版时间：31 August 2010
• 年：2010
• 卷：360
• 期：1-2
• 页码：39-46
• 全文大小：585 K

文摘

Fab antibody display on filamentous phage is widely applied to de novo antibody discovery and engineering. Here we describe a phagemid system for the efficient display and affinity selection of Fabs through linkage to the minor coat protein pIX. Display was successful by fusion of either Fd or Lc through a short linker to the amino terminus of pIX and co-expression of the counter Lc or Fd as a secreted, soluble fragment. Assembly of functional Fab was confirmed by demonstration of antigen-specific binding using antibodies of known specificity. Phage displaying a Fab specific for RSV-F protein with Fd linked to pIX showed efficient, antigen-specific enrichment when mixed with phage displaying a different specificity. The functionality of this system for antibody engineering was evaluated in an optimization study. A RSV-F protein specific antibody with an affinity of about 2 nM was randomized at 4 positions in light chain CDR1. Three rounds of selection with decreasing antigen concentration yielded Fabs with an affinity improvement up to 70-fold and showed a general correlation between enrichment frequency and affinity. We conclude that the pIX coat protein complements other display systems in filamentous phage as an efficient vehicle for low copy display and selection of Fab proteins.