What is Diphtheria?

Diphtheria is caused by toxin-producing Corynebacterium diphtheriae; the diphtheria toxin forms the characteristic pharyngeal pseudomembrane and can damage heart and nerves.

It spreads by respiratory droplets and is vaccine-preventable (DTP). Anti-diphtheria-toxoid IgG ELISA is central to assessing protective immunity and vaccine responses.

Transmission & symptoms

Corynebacterium diphtheriae spreads by respiratory droplets and direct contact. Toxigenic strains produce diphtheria toxin, which halts host protein synthesis by ADP-ribosylating elongation factor 2, forming the characteristic grey pharyngeal pseudomembrane and, systemically, damaging the heart and peripheral nerves.

Diagnosis & serology

Immunity is assessed by measuring anti-diphtheria-toxoid IgG, the accepted correlate of protection used across vaccine and seroprevalence studies. Toxigenicity of isolates is confirmed by toxin detection, while ELISA quantifies antitoxin antibody levels.

Research applications

Research applications include diphtheria-toxin biology (its receptor is HB-EGF/proHB-EGF on the EGFR axis), antitoxin and toxoid-vaccine immunogenicity, and cardiac/neural injury markers such as troponin during toxin-mediated disease.