Adherence and Cytotoxicity of Acinetobacter baumannii on Human Cervical Carcinoma Epithelial Cells: Exploring the Role of Anti-OmpA Antibodies

Abstract

We investigated the invasion of Acinetobacter baumannii strains to epithelial cells and elucidated the role of antibodies against outer membrane protein A (OmpA). A. baumannii ATCC 19606 and clinical isolate 58ST were utilized. OmpA was expressed, purified, and administered to BALB/c mice, inducing anti-OmpA antibodies. OmpA cytotoxicity was evaluated. Two A. baumannii strains were selected to infect human cervical HeLa cells. Serum resistance was determined at sera dilutions. Adhesion, internalization, and proliferation of live and killed A. baumannii in HeLa cells were examined with and without anti-OmpA sera. HeLa cell viability was assessed with and without exposure of live A. baumannii strains to anti-OmpA sera. Cytoskeleton inhibitor experiments were conducted on epithelial cells to probe microfilament and microtubule involvement in A. baumannii invasion. OmpA prompted antibody production without toxicity in mice. A. baumannii strains displayed varying cell invasion abilities, notably the clinical strain exhibiting the highest invasion. A. baumannii cells localized within vacuoles during internalization, migrating towards the nucleus, using a zipper-like invasion process. Bacterial proliferation within host cells led to HeLa cell death. Pre-treatment with anti-OmpA antibodies significantly curbed adhesion and invasion of A. baumannii in HeLa cells. Microscopic imaging provided proof of the intracellular presence of A. baumannii in HeLa cells. In conclusion, the OmpA plays a crucial part in A. baumannii - epithelial cell interactions. The results add to our knowledge of pathogenesis during the initial stages of infection by A. baumannii.