Anti-OmpA antibodies as potential inhibitors of Acinetobacter baumannii biofilm formation, adherence to, and proliferation in A549 human alveolar epithelial cells

• Published in: Microbial pathogenesis 2024-01, Vol.186, p.106473-106473, Article 106473
• Main Authors: Barati, Hamideh, Fekrirad, Zahra, Jalali Nadoushan, Mohammadreza, Rasooli, Iraj
• Format: Article
• Language: English
• Subjects: A549; Acinetobacter baumannii; Acinetobacter baumannii - metabolism; Adherence; Alveolar Epithelial Cells; Animals; Bacteria; Biofilms; Cell Proliferation; Cytotoxicity; Humans; Internalization; Mice; OmpA
• ISSN: 0882-4010; 1096-1208
• DOI: 10.1016/j.micpath.2023.106473

Outer membrane protein A (OmpA) is a critical virulence factor in Acinetobacter baumannii, influencing adhesion, biofilm formation, host immune response, and host cell apoptosis. We investigated the invasion of A549 alveolar epithelial cells by A. baumannii and examined how anti-OmpA antibodies impact these interactions. OmpA was expressed and purified, inducing anti-OmpA antibodies in BALB/c mice. The potential toxicity of OmpA was evaluated in mice by analyzing histology from six organs. A549 cells were exposed to A. baumannii strains 19606 and a clinical isolate. Using cell culture and light microscopy, we scrutinized the effects of anti-OmpA sera on serum resistance, adherence, internalization, and proliferation of A. baumannii in A549 cells. The viability of A549 cells was assessed upon exposure to live A. baumannii and anti-OmpA sera. OmpA-induced antibody demonstrated potent bactericidal effects on both strains of A. baumannii. Both strains formed biofilms, which were reduced by anti-OmpA serum, along with decreased bacterial adherence, internalization, and proliferation in A549 cells. Anti-OmpA serum improved the survival of A549 cells post-infection. Pre-treatment with cytochalasin D hindered bacterial internalization, highlighting the role of actin polymerization in invasion. Microscopic examination revealed varied interactions encompassing adherence, apoptosis, membrane alterations, vacuolization, and damage. A549 cells treated with anti-OmpA serum exhibited improved structures and reduced damage. The findings indicate that A. baumannii can adhere to and proliferate within epithelial cells with OmpA playing a pivotal role in these interactions, and the complex nature of these interactions shapes the intricate course of A. baumannii infection in host cells. •Virulence factors and secretion systems contribute to pathogenesis of A. baumannii.•OmpA is the major virulence factor of A. baumannii associated with autophagy.•Anti-OmpA antibodies play a role in adhesion, proliferation, and A549 response.•OmpA could be a therapeutic target and theoretical basis for A. baumannii infections.•OmpA, a crucial virulence factor, contributes to the incomplete autophagy.