Table of Contents
Molecular Biology International
Volume 2010 (2010), Article ID 628153, 7 pages
Research Article

Expression of a Gene Encoding 34.9 kDa PPE Antigen of Mycobacterium avium subsp. paratuberculosis in E. coli

Gene Expression Laboratory, Division of Animal Biotechnology, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh 243 122, India

Received 4 January 2010; Accepted 25 March 2010

Academic Editor: Mouldy Sioud

Copyright © 2010 Rajib Deb and P. P. Goswami. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Mycobacterium avium subsp. paratuberculosis (Map) contains PPE family antigens which are Proline and glutamic acid rich and may play important role as T cell antigens. Hence the identification and generation of antigens are necessary for immunological characterization. In the present study, the epitopic region of a unique PPE gene encoding 34.9 kDa protein from Map was amplified by polymerase chain reaction. The gene was cloned into Escherichia coli vector pQE30 UA. The recombinant plasmid designated as pQPPE was transformed into E. coli M15 and induced with IPTG revealed the high level expression of 37.1 kDa His-fusion protein (34.9 kDa PPE and 2.2 kDa His-tag), which was confirmed by immunoblotting. Recombinant PPE protein was then purified by Ni-NTA agarose chromatography. The polyclonal antiserum raised against purified recombinant PPE protein reacted with expressed 37.1 kDa His-fusion protein as well as with Map sonicate. The protein elicited significant delayed type hypersensitivity (DTH) skin reaction in mice sensitized with Map. The results indicated that the recombinant PPE protein of Map was associated with cellular immune response.