Question

How does lactoferrin interact with Corynebacterium diphtheriae's mechanism of action?

Answer 1

Corynebacterium colonizes and replicates in the upper respiratory tract and elaborates the potent exotoxin diphtheria toxin (DT), which is responsible for much of the morbidity associated with this disease. Transcription of the tox gene, which encodes DT, is regulated by iron with optimal expression occurring in low-iron environments, a condition that is predicted to exist at the site of colonization in the host. The iron regulation of tox transcription is mediated by the DtxR repressor, which similarly controls the expression of numerous genes in C. diphtheriae, many of which are involved in iron transport and metabolism

The acquisition and utilization of iron are essential for the growth of almost all bacte.ria and are required by most pathogens to cause disease. Although essential for virulence, iron is not easily available to invading bacterial pathogens since much of it is sequestered intracellularly by heme, which is bound primarily by hemoglobin. In the extracellular environment, much of the iron is bound by the host glycoproteins transferrin and lactoferrin. To survive in the iron-limited environment of the host, bacteria have evolved a variety of iron- and heme-scavenging systems, including high-affinity siderophore iron transporters as well as receptor-mediated mechanisms to import hemin through the cell wall and into the cytosol