Bacterial lactoferrin-specific iron acquisition receptor (LbpAB)

The bacterial lactoferrin-specific iron acquisition receptor is a specialized protein complex found on the surface of certain Gram-negative pathogens, such as Neisseria meningitidis and Neisseria gonorrhoeae [1, 8]. This receptor system is essential for bacterial survival and pathogenesis within the human host, as it allows the bacteria to hijack iron from host lactoferrin [2, 9]. Host lactoferrin is a glycoprotein that normally sequesters iron to limit microbial growth, a process known as nutritional immunity [8, 12]. The receptor complex typically consists of two components: Lactoferrin-binding protein A (LbpA) and Lactoferrin-binding protein B (LbpB) [1, 11]. LbpA is a TonB-dependent integral membrane transporter that moves iron across the outer membrane, while LbpB is a surface-exposed lipoprotein that facilitates lactoferrin capture [2, 14]. Beyond iron acquisition, LbpB also provides protection against host antimicrobial peptides, such as lactoferricin, by neutralizing their cationic charge [12, 15]. Due to its critical role in nutrient acquisition and its surface accessibility, the receptor is a prominent target for vaccine development [3, 11]. Experimental vaccines aim to elicit bactericidal antibodies that block iron uptake or promote immune-mediated destruction of the pathogen [3, 10]. Furthermore, the receptor's specificity is being exploited in targeted drug delivery systems using lactoferrin-functionalized nanoparticles to deliver antibiotics directly to bacteria [4, 6]. These strategies represent promising approaches to combat antibiotic-resistant infections and improve therapeutic efficacy [5, 7].

Other names

Lactoferrin-binding protein complexLbpA/LbpB receptorLbp receptorMeningococcal lactoferrin receptorLactoferrin-binding protein ALactoferrin-binding protein B

Vaccines targeting these receptors induce bactericidal antibodies that block the binding of host lactoferrin or the subsequent transport of iron, leading to bacterial starvation and immune-mediated lysis [3, 11]. In targeted drug delivery, the receptor's high affinity for lactoferrin is used to internalize lactoferrin-conjugated nanoparticles containing antimicrobial agents, thereby increasing local drug concentration and overcoming bacterial defense mechanisms [4, 6].