Nanoscale clustering by O-antigen-Secretory Immunoglobulin-A binding limits outer membrane diffusion by encaging individualSalmonellacells

• DOI: 10.1101/2023.07.13.548943
• Publication Date: 2023-07-15T05:00:11Z
• Authors: Alyson Hockenberry; Milad Radiom; Markus Arnoldini; Yagmur Turgay; Matthew Dunne; Jozef Adamcik; Beth Stadtmueller; Raffaele Mezzenga; Martin Ackermann; Emma Slack
• Keywords: Immunoglobulin A; Proteolysis

Abstract Secreted immunoglobulins, predominantly SIgA, influence the colonization and pathogenicity of mucosal bacteria. While part this effect can be explained by SIgA-mediated bacterial aggregation, we have an incomplete picture how SIgA binding influences cells independently aggregation. Here show that akin to microscale crosslinking cells, targeting Salmonella Typhimurium O-antigen extensively crosslinks O-antigens on surface individual at nanoscale. This results in essentially immobilized outer membrane. Membrane immobilization, combined with Bam-complex mediated membrane protein insertion biased inheritance IgA-bound O-antigen, concentrating SIgA-bound oldest poles during cell growth. By combining empirical measurements simulations, SIgA-driven increases rate which phase-varied daughter become IgA-free: a process accelerate IgA escape via phase-variation structure. Our O-antigen-crosslinking impacts workings membrane, helping mechanistically explain may exert aggregation-independent effects microbes colonizing mucosae.