9ZRT

Shigella flexneri type III secretion system (T3SS) protein IpaD bound to hemolysis blocking antibody fragment D13r-34

Summary for 9ZRT

• Entry DOI: 10.2210/pdb9zrt/pdb
• EMDB information: 74630
• Descriptor: Invasin IpaD, D13r-34 antibody fragment heavy chain, D13r-34 antibody fragment light chain (3 entities in total)
• Functional Keywords: t3ss, epitope, vaccine antigen, sipd homolog, protein transport
• Biological source: Shigella flexneri; More
• Total number of polymer chains: 3
• Total formula weight: 87695.60

Authors

Gilman, M.S.A.,Kruse, A.C.,Schmidt, H.R. (deposition date: 2025-12-20, release date: 2026-09-16)

Primary citation

Gallant, R.M.,Savarino, P.,Pulido, S.,Gilman, M.S.A.,Lu, T.,Hayes, J.,Xerri, N.L.,Williams, T.,Ochoa, M.A.,Dietz, Z.,Peterson, E.,Scott, T.,Hartmann, F.,Baker, S.G.,Kaminski, R.W.,Sok, D.,Kruse, A.C.,Picking, W.,Capuano, S.V.,Schmidt, H.R.
Multifunctional antibody responses from a primate Shigella outbreak inform vaccine design.
Sci Transl Med, 18:eaef7084-eaef7084, 2026

PubMed Abstract: There is currently no approved vaccine for spp., a leading cause of diarrhea with increasing rates of antimicrobial resistance. vaccine development is complicated in part by an incomplete understanding of the structural and molecular determinants of immunity. To address this, we isolated monoclonal antibodies against candidate vaccine antigens using samples from a outbreak in a nonhuman primate (NHP) research facility. We found that antibodies targeting the O-antigen can undergo substantial affinity maturation (>10%) to acquire broad cross-reactivity across serotypes. We also found that the virulence-associated type III secretion system (T3SS) proteins IpaD and IpaB elicit moderate T cell and robust antibody responses. T3SS antibodies could either inhibit or enhance bacterial virulence in vitro and differed in vivo depending on their epitope specificity. Collectively, these findings provide insights into protective and deleterious immune responses against that directly inform vaccine immunogen design.

PubMed: 42685149
DOI: 10.1126/scitranslmed.aef7084

Experimental method

ELECTRON MICROSCOPY (3.3 Å)