title: Human immunoglobulin G antibody response to the major gonococcal iron-regulated protein.
abstract: In humans, gonococcal infection occurs in environments limited with respect to free iron. Neisseria gonorrhoeae produces increased quantities of iron-regulated membrane proteins when grown under in vitro conditions which restrict the availability of free iron. Using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot (immunoblot) techniques, we studied the reactivity of specific antibodies to the 37-kilodalton (kDa) major iron-regulated protein (MIRP) of gonococci grown under iron-limiting conditions. Antibodies reactive with the 37-kDa MIRP were distinguished from those reactive with protein I by using purified 37-kDa MIRP or gonococcal protein preparations. Acute-phase sera from patients with disseminated gonococcal infection (DGI) reacted strongly to both the 37-kDa MIRP and protein I. Acute sera from nine patients with uncomplicated gonorrhea did not exhibit strong reactivity with the 37-kDa MIRP and were indistinguishable from five control sera. When compared with acute-phase sera, convalescent-phase sera from patients with DGI failed to demonstrate increased reactivity, whereas convalescent-phase sera from one of nine patients with uncomplicated gonorrhea developed reactivity to the 37-kDa MIRP. These data indicate that (i) the 37-kDa MIRP is expressed and antigenic in vivo and (ii) humans with DGI consistently develop a systemic antibody response to the 37-kDa MIRP.
mesh_terms: D000907:Antibodies, Bacterial / Q000276:immunology*; D000942:Antigens, Bacterial / Q000276:immunology*; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology*; D001426:Bacterial Proteins; D004591:Electrophoresis, Polyacrylamide Gel; D006069:Gonorrhea / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D007501:Iron / Q000502:physiology; D033862:Iron-Binding Proteins; D008970:Molecular Weight; D009344:Neisseria gonorrhoeae / Q000276:immunology*; D033902:Periplasmic Binding Proteins
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D007074:Immunoglobulin G; D033862:Iron-Binding Proteins; D033902:Periplasmic Binding Proteins; D007501:Iron