Revisiting Host-Binding Properties of LigA and LigB Recombinant Domains

Author(s)

Pires, Henrique M. ; Silva, Igor R. M. ; Teixeira, Aline F. ; Nascimento, Ana L. T. O.

• Document type: Journal article
• Source: MICROORGANISMS; v. 13, n. 6, p. 16-pg., 2025-05-31.

Abstract

Pathogenic bacteria of the genus Leptospira are the etiological agents of leptospirosis, a disease that affects humans and animals worldwide. Despite the increasing number of studies, the mechanisms of leptospiral pathogenesis remain poorly comprehended. In this study, we report various interactions of the LigA7'-13' and LigB1'-7' domains with host components. The LigA7'-13' and LigB1'-7' were cloned into the pET28a vector, and the recombinant proteins were expressed in E. coli C43 (DE3) and E. coli BL21 (DE3), respectively. Both recombinant protein domains were expressed in soluble form and purified using nickel-chelating chromatography. The rLigA7'-13' and rLigB1'-7' domains exhibited binding to several types of integrins, with most interactions occurring in a dose-dependent and saturable manner, consistent with the characteristics of typical receptor-ligand interactions. The recombinant domain LigA7'-13' demonstrated affinity for the glycosaminoglycans (GAGs) chondroitin-4-sulfate, chondroitin sulfate, heparin, chondroitin sulfate B, and heparan sulfate, while no binding was detected for LigB1'-7' with these molecules. Both rLigA7'-13' and rLigB1'-7' interacted with components of the terminal complement pathway and were capable of recruiting C9 from normal human serum (NHS). These interactions may inhibit the formation of polyC9, ultimately preventing the assembly of the membrane attack complex (MAC). Collectively, our data expand the repertoire of host components that interact with rLigA7'-13' and rLigB1'-7', opening new avenues for understanding leptospiral immune evasion and broadening the roles of these domains in bacterial virulence. (AU)

• FAPESP's process: 22/08985-5 - Assessment of the role of two proteins of Leptospira interrogans in the pathogenesis and in the immunoprotective activity in animal model
• Grantee: Igor Rodolpho Matheus Silva
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 19/17488-2 - Advancing the understanding of pathogenesis and virulence of Leptospira interrogans through proteomics, structural, mutagenesis and immunological analyses
• Grantee: Ana Lucia Tabet Oller do Nascimento
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 16/11541-0 - Evaluation of the vaccine potential of antigenic fractions obtained in Leptospira interrogans serovar Copenhageni using hamsters as an animal model
• Grantee: Aline Florencio Teixeira
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 19/05466-4 - Identification of leptospiral antigens recognized by gamma/delta T cells as target for development of next generation vaccines
• Grantee: Aline Florencio Teixeira
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor