Pathogen Adhesins and Toxins

Pathogen adhesins and toxins represent a broad class of virulence factors that are essential for the initiation and progression of infectious diseases [1, 3]. Adhesins are specialized surface proteins or appendages, such as fimbriae and pili, that enable bacteria, viruses, and parasites to attach to specific host cell receptors, facilitating colonization and tissue invasion [1, 11, 12]. Toxins are secreted or surface-bound molecules that exert harmful effects on the host, ranging from direct cell lysis via pore formation to the disruption of critical intracellular signaling pathways through enzymatic activity [4, 15, 16]. Unlike traditional antibiotics that target essential microbial survival processes, anti-virulence therapies aim to neutralize these specific factors, thereby reducing pathogenicity without imposing strong selective pressure for the development of antimicrobial resistance [2, 6]. Clinical applications include the use of monoclonal antibodies to neutralize bacterial toxins like those from Clostridioides difficile and Bacillus anthracis, as well as viral attachment proteins like the RSV F protein and the SARS-CoV-2 spike protein [11, 15].

Other names

Virulence factorsMicrobial adhesinsBacterial toxinsAnti-virulence targetsPathogen attachment proteins

Drugs targeting pathogen adhesins and toxins primarily work through direct neutralization, where monoclonal antibodies bind to the virulence factor to prevent its interaction with host receptors or to block its enzymatic/pore-forming activity [4, 5, 15]. Anti-adhesion agents competitively inhibit the binding of microbial surface proteins to host cells, thereby preventing colonization [1, 9, 11]. Anti-toxin agents may also block the assembly or translocation of multi-subunit toxins into the host cytoplasm [15, 16].