Selection of an Aptamer Against Surface Exposed Targets on Yersinia Pestis

Abstract

Yersinia pestis is a CDC 'category A' bioterrorism agent. This study attempts to select an aptamer to detect the presence of LOS and F1 antigen on Y. pestis. Aptamer selection by Systematic Evolution of Ligand by Exponential Enrichment is an iterative process of binding, partitioning, amplification and strand separation.The Lipid A as well as the core polysaccharide of LOS was found unfavorable for aptamer binding. Purified F1 antigen was considered a suitable target for aptamer selection. Our partitioning method using electrodialysis and eight rounds of selection resulted in thirty nine clones from Round 8 with a consensus motif -GTGAG--GTTG--. However, binding assays were unsuccessful due to non-specificity of Round 8 to F1 antigen, and and hence additional four rounds of SELEX are being carried out. The aptamer thus selected might be used in in vitro diagnostic assays to detect F1 antigen of Yersinia pestis.