Lactoferrin-binding protein A and Lactoferrin-binding protein B (LbpA/LbpB)

Bacterial lactoferrin-binding proteins LbpA and LbpB form a specialized two-component receptor complex on the surface of certain Gram-negative pathogens, including Neisseria meningitidis, Neisseria gonorrhoeae, and Moraxella catarrhalis [3, 6]. This system is primarily responsible for iron piracy, the process of extracting essential iron from host lactoferrin to support bacterial growth in the iron-limited environment of the human mucosa [3, 25]. LbpA is a TonB-dependent outer membrane transporter that acts as a gated pore for iron entry, while LbpB is a surface-exposed lipoprotein that facilitates the capture of iron-loaded lactoferrin and provides protection against host-derived antimicrobial peptides like lactoferricin [3, 7, 28]. Because these proteins are surface-exposed and critical for virulence, they are being investigated as promising vaccine candidates to prevent invasive meningococcal disease and gonorrhea [1, 18, 21]. However, the high degree of sequence diversity in LbpB and the ability of the bacteria to regulate expression through phase variation present significant challenges for achieving broad therapeutic coverage [1, 6, 29]. Experimental vaccines targeting these proteins aim to induce bactericidal antibodies that block iron acquisition and promote complement-mediated killing of the pathogen [1, 11].

Other names

Lactoferrin receptorMeningococcal lactoferrin receptorLbpALbpBLactoferrin-binding protein complex

Induction of bactericidal antibodies that block iron acquisition from host lactoferrin and promote complement-mediated bacterial lysis [1, 11].