Pertussis toxin S1 subunit (PTx-S1) (PTx-S1)

Pertussis toxin (PTx) is a major virulence factor produced by Bordetella pertussis, the causative agent of whooping cough [1][3]. It is an AB5-type exotoxin consisting of an enzymatic A-subunit (S1) and a pentameric B-subunit (S2, S3, two S4s, and S5) responsible for cell binding and translocation [4]. The S1 subunit functions as an ADP-ribosyltransferase that modifies the alpha subunits of inhibitory G proteins (Gi/o), leading to the accumulation of cAMP and disruption of various cellular signaling pathways, particularly in immune cells [1][4]. The conformational epitope located on the S1 subunit near the S4/S5 interface is a critical site for toxin neutralization [2]. Therapeutic strategies, including acellular vaccines and monoclonal antibodies like HuMab-1B7, target this region to block the toxin's ability to interact with host cell receptors or to inhibit its enzymatic activity, thereby mitigating the severe paroxysmal coughing and lymphocytosis associated with the disease [2][3].

Other names

Pertussis toxin subunit 1PtxAIslet-activating proteinPTx-S1 subunitADP-ribosyltransferase subunit of pertussis toxinPertussis toxin holotoxin S1 subunit conformational epitope near S4/S5 interface

Neutralizing antibodies bind to the S1 subunit or the S1-B pentamer interface to prevent toxin entry into host cells or to inhibit the enzymatic ADP-ribosylation of inhibitory G proteins (Gi/o).