Echinococcus granulosus antigen B acts as an LPS-scavenging lipoprotein in vitro preventing TLR4-mediated activation of dendritic cells

Lagos Magallanes, Sofía - Beasley Lomazzi, Anaclara - Zamarreño, Fernando - Carrión, Federico - Fló, Martín - Dutto, Jerónimo - Julve, Josep - Costabel, Marcelo - Maccioni, Mariana - Folle, Ana Maite - Ferreira, Ana María

Resumen:

Echinococcus granulosus sensu lato antigen B (EgAgB) is a major parasite lipoprotein, produced by the hydatid and released at the host-parasite interface. Accumulating evidence supports that EgAgB may exert immunomodulatory effects on myeloid cells; however, the underlying molecular mechanisms remain poorly understood. We examined the impact of native EgAgB (nEgAgB) and recombinant EgAgB8/1 (rEgAgB) on lipopolysaccharide (LPS)-induced activation of bone marrow-derived dendritic cells (BMDC), to help elucidate these mechanisms. Both immunoaffinity-purified nEgAgB or rEgAgB induced modest BMDC activation, indicated by the production of IL-6, IL-12p40, and nitric oxide, but not IFN-β. This activation was primarily attributed to LPS traces in EgAgB preparations since it was nearly abolished by a specific TLR4 inhibitor and in Tlr4-/- BMDC, while EgAgB binding to BMDC was TLR4-independent. Notably, both nEgAgB and rEgAgB inhibited LPS-induced cytokine and nitric oxide production, and disrupted TLR4 dimerization and endocytosis. Competitive binding assays showed that EgAgB and human high-density lipoprotein (hHDL) similarly inhibited LPS binding to macrophages and BMDC; however, EgAgB more effectively suppressed LPS-induced cytokine secretion. Contrastingly, EgAgB did not modulate BMDC responses to lipoteichoic acid, unlike hHDL. Using dynamic light scattering and an ELISA-like assay, we demonstrated a higher potential of EgAgB to bind LPS than hHDL. Additionally, docking analyses suggest the presence of a defined LPS-binding interface in EgAgB8/1 subunit. Overall, these findings reveal a novel binding property of EgAgB, which enables it to act as an extracellular LPS scavenger, interfering with TLR4-mediated LPS recognition and downstream proinflammatory responses in myeloid cells.

Detalles Bibliográficos
2026
Universidad de la República. Comisión Sectorial de Investigación Científica
Programa de Desarrollo de las Ciencias Básicas
Agencia Nacional de Investigación e Innovación
Agencia Estatal de Investigación (España)
Ministerio de Ciencia e Innovación (España)
Echinococcus granulosus
Parasite lipoprotein
Antigen B
Dendritic cell activation
Inmunomodulation
LPS
Ciencias Naturales y Exactas
Ciencias Biológicas
Inglés
Agencia Nacional de Investigación e Innovación
REDI
https://hdl.handle.net/20.500.12381/5492
https://doi.org/10.1128/iai.00361-25
Acceso abierto
Reconocimiento 4.0 Internacional. (CC BY)