The docking was performed using the HDOCK software, and the docked structure is shown in Figure . Based on the analysis, most of the antibodies bind to the apical region of the protein, as shown in Figure . The apical region is where the antibody, the protein, and the HpaA protein bind to the annexin; therefore, inhibiting this binding site will be crucial for bacteria binding to the human cell. were selected for the next analysis. I compute the binding energy between the adhesin protein and antibody in the second selection criterion. Binding energy is the energy required to separate a system of particles; it represents the strength of the bonds holding the system together. Based on PRODIGY software, the seven antibodies have the following binding energy: 4a6y (-21.3 kcal/mol), 1iqw(-17.6 kcal/mol), 1b4j(-17.6 kcal/mol), 1f8t(-17.6 kcal/mol), 1nlb(-16.6 kcal/mol), 1fl5(-15.0 kcal/mol), and 2hrp (-14.3 kcal/mol) (Table ). A hydrogen bond is when a hydrogen atom, covalently bonded to a highly electronegative atom like nitrogen, oxygen, or fluorine, experiences an attraction to another electronegative atom in a nearby molecule or within the same molecule. I used hydrogen bonds to measure the binding strength between the antibody and the protein (Table ). Through the antibody selection criteria, antibody 1IL1 was selected as the most appropriate candidate for inhibiting bacteria and gut epithelial cell binding interaction. This antibody will bind to the apical region of an HpaA protein and can prevent the HpaA-annexin protein interaction.