EnzyPha, An Engineered Helper Phage Developed to Overcome most of the Limitations Regarding Phage Titration and ELISA Tests

Abstract

Introduction: The phage display method is a technology that enables the expression of exogenous polypeptides on the surface of bacteriophage particles. Phage titration and ELISA are applied to measure helper phage particles or polypeptide bearing phages and also eva luation the inter-action between polypeptide bearing phages and coated antigens, respectively. Although several procedures have been introduced to perform phage titration and ELISA, they face some limitations, such as being time-consuming, expensive, and low reproducibility. Materials and Methods: We developed a new system called EnzyPha by engineering the M13KO7 expressing Secreted Acid Phosphatase of Mycobacterium tuberculosis (SapM enzyme) on its pIX protein for applying in colorimetric phage titration and ELISA methods. To evaluate the idea, colorimetric phage titration and ELISA were performed and compared to the traditional methods. Results: SapM enzyme was expressed on the pIX protein of M13KO7 properly. The colorimetric phage titration and phage ELISA showed better and comparable results against the traditional approaches. Conclusions: The results showed that the proposed model would titrate phages more sensitively than the plating titration method through a shorter timeframe. Moreover, it could be a better alternative to the routine phage ELISA due to time-saving, cost-effectiveness, and higher sensitivity. © 2023 The Author(s).