en Immune responses, deficiencies and vaccine candidates Immune responses, deficiencies and vaccine candidates Original article Original article <b><span style="font-size:10.0pt"><span style="line-height:107%"><span new="" roman="" style="font-family:" times="">Introduction</span></span></span></b><span style="font-size:10.0pt"><span style="line-height:107%"><span new="" roman="" style="font-family:" times="">: Antibiotic-resistant <i>Pseudomonas aeruginosa</i> has been designated by the World Health Organization (WHO) as a critical priority pathogen, highlighting the critical need for developing new strategies, particularly prophylactic measures. This research focuses on incorporating highly antigenic elements from essential, surface-exposed outer membrane proteins of <i>P. aeruginosa</i> to design a polypeptide-based subunit vaccine capable of inducing a strong immune response, using immunoinformatics approaches. <b>Methods</b>: Ten essential outer membrane proteins of <i>P. aeruginosa</i> were analyzed using three online servers (ABCpred, BCPREDS, and LBtope) to predict B-cell epitopes and the IEDB server to predict CD8+ and CD4+ T-cell epitopes. The predicted epitopes were then assessed for physicochemical properties, allergenicity, and toxicity using relevant web servers. A vaccine construct incorporating the selected epitopes and an adjuvant was designed, and its 3D structure was modeled to study its interaction with Toll-like receptor-4 (TLR-4). <b>Results:</b> The final vaccine construct consisted of a 478-amino acid polypeptide incorporating 5 CD8+ T-cell, 5 CD4+ T-cell, and 15 B-cell epitopes. <i>In silico</i> analysis predicted the vaccine construct to be immunogenic, non-toxic, non-allergenic, and possess favorable physicochemical properties. Molecular docking simulations predicted strong binding affinity between the vaccine construct and TLR-4, suggesting its potential to elicit a robust immune response. <b>Conclusion</b>: These <i>in silico</i> analyses suggest that the designed subunit vaccine is potentially safe and effective against <i>P. aeruginosa</i>. However, experimental validation is necessary to confirm these predictions. </span></span></span><br> &nbsp; Pseudomonas aeruginosa, Vaccine development, Subunit vaccine, Epitope prediction, Immunoinformatics, Humoral immunity, Outer membrane proteins 190 200 http://jommid.pasteur.ac.ir/browse.php?a_code=A-10-590-1&slc_lang=en&sid=1 Masoumeh Fathi masoumehfathi87@gmail.com 0009-0006-4769-1939 Yes Department of Microbiology, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.