10.22376/ijpbs.2019.10.1.p1-12 Volume 5 Issue 2 2014 (April - June) In the present study we cloned and characterized the cagN gene from Helicobacter pylori to develop an antigen for the protective immunity against gastric helicobacter. The cagN gene from Helicobacter pylori was amplified using specific primers and cloned in pTZ57R/T and transformed into DH5α cells. The plasmid DNA obtained was then confirmed by restriction digestion and sequence analysis. The sequence was found to be 99% similar to that obtained in GenBank. The sequence of cagN gene amplified by the specific primer is closely matched (99%) with a Helicobacter pylori strains. The gene restricted from the cloning vector was ligated to expression vector. Transformation was confirmed with plasmid extraction and followed by restriction digestion. IPTG was used as an inducer for the expression of cagN protein and the protein was successfully isolated and quantified. The quantified protein was subjected to SDS PAGE to evaluate the expression of that protein. After staining with coomassie staining a specific band was observed at an approximate molecular weight of ~20 KDa. The discovery of a protective antigen of Helicobacter pylori offers further hope that an effective vaccine can be produced for human usage BASSAM SHAKER MAHMOOD , SELVAM ARJUNAN AND RADHAKRISHNAN SENTHILKUMAR Helicobacter Pylori, Cag, Gastric Cancer, Cloning and Expression 588-595