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RU 848

A Novel Epitope Tag and Highly Sensitive Monoclonal Antibodies for Improved Immunodetection of Tagged Proteins

Researchers studying certain proteins of interest require tools to detect these proteins with regards to their location in the cell and/or tissues, and also to be able to purify them.  The method of epitope tagging is a tool commonly used for these purposes and involves adding a molecular tag that can then be recognized by an antibody against that tag.  This method is particularly useful in the many cases where there are no antibodies specific to the protein of interest.

Our scientists have prepared a number of monoclonal antibodies (mAbs) against recombinant mouse Langerin, which also contained a linker sequence from the E. coli protein OmpF and a FLAG epitope.  In doing so, they have identified two mAbs that were not reactive to Langerin, but show remarkable efficacy in immunodetection methods.  The L5 mAb recognizes the FLAG epitope, and has been shown to be better than many conventional anti-FLAG mAbs, while the OLLA-2 mAb recognizes a novel epitope named OLLAS with great sensitivity.  These novel reagents are ideal for immunodetection of tagged proteins and have great potential to be valuable research tools.


  • The novel pair of the OLLAS epitope and the OLLA-2 mAb exhibits a ~100-fold increase in sensitivity compared to binding of commercially available antibodies to FLAG.
  • The OLLAS epitope can be fused at the C-terminal, N-terminal, and internal sites of recombinant and fusion proteins, including engineered monoclonal antibodies, without interfering with the biological activities of those proteins.
  • The OLLAS epitope can improves expression of recombinant proteins as an inter-molecular linker between two recombinant proteins.
  • Both the OLLA-2 mAb and L5 mAb are rat IgG antibodies, providing another option to other commercially available antibodies that are mainly mouse monoclonals or rabbit polyclonals.

Area of Application             

Epitope tagging and immunodetection of tagged proteins

Stage of Development

Both mAbs and the OLLAS epitope have been used efficiently and successfully in a variety of immunodetection methods.

Lead Inventors

Ralph M. Steinman & Dr. Chae Gyu Park

Patent Information & References

  • S. Patents 7,943,345; 8,114,634; and 8,865,871
  • Park, S.H., et al. 2008. Immunol. Methods, 331:27-38.

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