Differential expression of "Fe-repressible" and "growth-rate-sensitive" proteins in Neisseria meningitidis and Neisseria gonorrhoeae.

By varying growth conditions, we were able to differentiate (SDS-PAGE) between true "Fe-repressible" proteins and "growth-rate-sensitive" proteins (GSP's) (60-110 Kd) in outer membranes of iron-starved meningococci and gonococci. Immunological characterization with monoclonal antibodies raised against the GSP's revealed (GIRA) crossreactivity between different GSP's. On the basis of common epitopes, two groups of proteins could be distinguished. Immuno-electron-microscopy showed that proteins of both groups were exposed at the cell surface.