Diphtheria toxin A-subunit (DTA)

The diphtheria toxin A-subunit (DTA) is the catalytic component of the diphtheria toxin produced by Corynebacterium diphtheriae and related species. DTA is responsible for the toxin’s action: after entering the host cell, it catalyzes the ADP-ribosylation of eukaryotic elongation factor 2 (EF-2), effectively halting protein synthesis and inducing cell death. The subunit alone cannot enter cells but is highly cytotoxic once inside. In clinical and research settings, DTA is used both as a tool for cell ablation and as a moiety in experimental targeted therapies, most notably in fusion proteins used for cancer treatment. The A-subunit is a validated therapeutic target in infectious disease (diphtheria) and oncology, where its potent cell death-inducing properties can be directed against unwanted cell populations. It poses substantial safety risks due to its extreme potency and potential for non-specific toxicity in systemic exposure.

Other names

DTAFragment ADiphtheria toxin catalytic subunitDiphtheria toxin A chain

Neutralization of toxin activity (antitoxins bind and inhibit) Preventing entry into host cells (by blocking receptor binding domain in engineered fusion proteins, thereby preventing DTA delivery) For immunotoxins, targeted delivery of DTA to specific cell types leads to EF-2 inactivation and cell death