Enrichment of Escherichia coli spheroplasts displaying scFv antibodies specific for antigens expressed on the human cell surface

Jun Kang Qiu, Sang Taek Jung, George Georgiou, Hai Ying Hang

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


Anchored periplasmic expression (APEx) is a method for isolating high affinity ligand-binding proteins from large combinatorial libraries, and antibodies highly specific for soluble antigens were successfully isolated from APEx antibody libraries in combination with flow cytometric sorting (Harvey et al., Proc Natl Acad Sci USA 101(25):9193-9198, 2004). However, many disease markers and drug targets are localized on the cell surface, and often, unique posttranslational modifications and/or properly folded epitopes are lost when they were expressed and isolated in soluble form. In this study, we demonstrate that Escherichia coli spheroplasts, displaying antibodies and screened by a combination of plate-panning and flow cytometric sorting, can be used for isolating antibodies specific for antigens on the human cell surface. Two rounds of plate-panning followed by one round of flow cytometric sorting resulted in 7,200-fold enrichment of antibodies specific for the protective antigen of Bacillus anthracis from a large excess of spheroplasts expressing a scFv antibody to digoxin (a negative control). There is the potential to use this technique for library screening to find novel antibodies against disease cell surface antigens.

Original languageEnglish
Pages (from-to)1385-1391
Number of pages7
JournalApplied Microbiology and Biotechnology
Issue number6
Publication statusPublished - 2010 Dec
Externally publishedYes

Bibliographical note

Funding Information:
Acknowledgments This work was supported by National Natural Science Foundation of China (30971604). S-T Jung and G. Georgiou gratefully acknowledge support by The Clayton Foundation.


  • Anchored periplasmic expression
  • Antigens on the human cell surface
  • ScFv
  • Spheroplasts

ASJC Scopus subject areas

  • Biotechnology
  • Applied Microbiology and Biotechnology


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