Gamma-hemolysin component A (HlgA) (HlgA)

Gamma-hemolysin component A (HlgA) is a secreted virulence factor produced by Staphylococcus aureus that plays a critical role in the pathogen's ability to evade the host immune system. It belongs to the family of bi-component beta-barrel pore-forming toxins, which require the synergistic interaction of an S-component (HlgA) and an F-component (HlgB) to function (UniProt, 2023). HlgA acts as the initial binding subunit, specifically targeting host cells such as neutrophils, monocytes, and macrophages by interacting with G protein-coupled receptors, including CXCR1, CXCR2, and CCR2 (Spaan et al., 2014). Once bound to the cell surface, HlgA recruits HlgB to form an octameric prepore that subsequently inserts into the lipid bilayer to create a stable aqueous pore. This pore formation leads to the leakage of intracellular contents, osmotic lysis, and ultimately the death of the host immune cell (Vandenesch et al., 2012). In clinical settings, HlgA is associated with a variety of staphylococcal diseases, including skin infections, pneumonia, and bacteremia. Because it is a key driver of inflammation and tissue damage, HlgA is considered a promising target for anti-virulence therapies, such as neutralizing monoclonal antibodies, which aim to disarm the bacteria without the selective pressure associated with traditional antibiotics.

Other names

HlgAGamma-hemolysin subunit AStaphylococcal gamma-hemolysin component AGamma-hemolysin chain A

Neutralization of the S-component to prevent receptor binding and the subsequent assembly of the functional octameric pore on host cell membranes.