OBTAINMENT AND CHARACTERIZATION OF AN IMMUNOGENIC CONJUGATE OF PSEUDOMONAS AERUGINOSA LIPOPOLYSACCHARIDE AND BOVINE SERUM ALBUMIN

ABSTRACT Pseudomonas aeruginosa is an etiologic agent of opportunistic infections mainly in immunocompromised patients. Its inherent feature of developing resistance to a wide range of antibacterial agents make it a critical point in infection control. In animals, problems with multidrug resistance occur in otitis, cystitis, uveo-conjunctivitis, endometritis and mastitis, and there is no commercially available vaccine. With the aim of improving its immunogenicity, the lipopolysaccharide (LPS) antigen was coupled to bovine serum albumin (BSA) with .-periodate as the reductive agent. The conjugation was evaluated by gel-permeation chromatography, by quantitating total sugar and protein, and both LPS and BSA were detected in similar proportions. The immunization of mice with LPS-BSA conjugate vaccine resulted in an agglutinating antibody response against P. aeruginosa lower than that obtained for a mixture of free LPS and BSA. They were 65% and 86% lower in the 6th and 10th weeks after the hyperimmunization procedure, respectively. This indicates that the conjugation reaction resulted in an immunogenic product, however its quality should be improved.摘要：铜绿假单胞菌（Pseudomonas aeruginosa）是引发免疫功能低下人群机会性感染的主要病原体。该菌对多种抗菌药物固有耐药的特性，使其成为感染防控领域的重点管控对象。在动物机体中，多重耐药性问题可见于中耳炎、膀胱炎、眼色素层结膜炎、子宫内膜炎及乳腺炎等病症，且目前尚无针对该菌的商用疫苗上市。为提升其免疫原性，研究团队以高碘酸盐（periodate）作为还原剂，将脂多糖（LPS）抗原与牛血清白蛋白（BSA）进行偶联。通过凝胶渗透色谱法、总糖与蛋白质定量检测对该偶联产物进行表征，结果显示LPS与BSA在偶联物中比例相近。采用LPS-BSA偶联疫苗免疫小鼠后，其产生的针对铜绿假单胞菌的凝集抗体应答水平，低于游离LPS与BSA混合物免疫组。在加强免疫程序后的第6周和第10周，该应答水平分别较混合制剂组低65%和86%。上述结果表明，本次偶联反应成功制备了具备免疫原性的产物，但其质量仍有待进一步优化。