A Potential Role for the Major Iron-Regulated Protein Expressed by Pathogenic Neisseria Species

Several iron-regulated proteins of Neisseria gonorrhoeae and Neisseria meningitidis have been reported. One of these, a 37,000-dalton protein is the major iron-regulated protein (MIRP) and appears to be common among all gonococcal and meningococcal isolates. This protein was purified from both N. gonorrhoeae and N. meningitidis and was found to contain ∼1 mole of Fe⁺⁺⁺/mole of protein. Sera from patients with gonococcal infections contained antibodies to the MIRP. Thus, the MIRP is expressed in vivo. The iron-binding nature of the MIRP suggests that it may have a role in iron acquisition by the pathogenic Neisseria species and, therefore, may have a function in their pathogenicity.