Detection of TNT-derivatives with recombinant phages

New immunoreagents for detection of TNT-derivatives TNP and TNP-Tris were developed using phage display technique. The monovalent and pentavalent recombinant phages carrying scFv specific for TNT were constructed and compared with each other to define the impact of valency and molecule dimension on antibody binding in immunoassay. Also, the bifunctional phages were generated, which carried TNT-specific scFvs as well as enzyme β-lactamase as a model marker on its surface. The most sensitive recombinant phages were selected and used for detection of TNP-Tris in a competitive ELISA based on immobilized antigen. Preincubation and partial phages saturation with a sample containing antigen allowed competition with immobilized hapten and displacement of free antigen. The phages exposing enzyme were used as immunoreagents for single step detection. The other phages were detected with specific marked antibodies. To date, the results presented in this paper are the first ever published regarding the recombinant phages for the detection of TNT.