Neisserial adhesin A – Siglec-5 interaction (NadA–Siglec-5)

Neisserial adhesin A (NadA) is a trimeric autotransporter protein found on the surface of Neisseria meningitidis, the primary causative agent of bacterial meningitis and sepsis (Benucci et al., 2024). It plays a critical role in the pathogen's life cycle by mediating high-affinity binding to human host cell receptors, specifically Siglec-5 (Sialic acid-binding Ig-like lectin 5), also known as CD170 (Spinello, 2020). Siglec-5 is an inhibitory receptor expressed primarily on myeloid cells, such as monocytes and neutrophils, and typically functions to dampen immune responses through its cytoplasmic immunoreceptor tyrosine-based inhibitory motifs (ITIMs) (Benucci et al., 2024). By engaging Siglec-5, NadA facilitates bacterial adhesion and invasion while potentially subverting host immune defenses by exploiting these inhibitory signaling pathways (Benucci et al., 2024). This interaction is a significant factor in the virulence of hypervirulent meningococcal strains and is a primary target of the 4CMenB (Bexsero) vaccine, which contains recombinant NadA as a key antigen (Benucci et al., 2024). Recombinant NadA in the vaccine induces bactericidal antibodies that prevent the bacteria from colonizing and invading host tissues (Benucci et al., 2024). Research into this interaction continues to inform the development of next-generation therapeutics and vaccines aimed at preventing invasive meningococcal disease.

Other names

NadA-CD170 interactionNeisserial adhesin A binding to Sialic acid-binding Ig-like lectin 5NadA-Siglec-5 complex

Induction of bactericidal antibodies against the NadA protein to block bacterial adhesion and invasion of host cells.