Experimental gonococcal urethritis and reinfection with homologous gonococci in male volunteers.
BACKGROUND
Reinfection, a common occurrence with gonorrhea, may result from a lack of protective immune response, or from the tremendous gonococcal strain variation.


OBJECTIVE
A two-phase study in human volunteers tested whether experimental infection with Neisseria gonorrhoeae MS11mkC would protect against reinfection with the same organisms.


METHODS
In phase 1, an intraurethral inoculum of 57,000 piliated, transparent (opacity protein-negative [Opa-]) MS11mkC N gonorrhoeae infected 14 of 15 (93%) volunteers. The volunteers were encouraged to delay treatment for at least 5 days. In phase 2, which began 2 weeks after treatment for the initial infection, volunteers were inoculated with 7,100 piliated, Opa- MS11mkC.


RESULTS
The phase 2 challenge infected 6 of 14 (43%) previously infected volunteers and 5 of 10 (50%) naïve control subjects. Phase 1 volunteers who resisted reinfection were significantly more likely to have had a fourfold or greater increase in lipooligosaccharide immunoglobulin G during phase 1 than those who did not resist reinfection (P = 0.026).


CONCLUSIONS
Although infection did not provide protection from reinfection under the conditions used, the results suggest that immunity to reinfection is more complex than anticipated by the experimental design.
Schmidt
K A
KA
Department of Bacterial Diseases, Walter Reed Army Institute of Research, Washington, DC, USA. katherine.a.schmidt@dartmouth.edu
Schneider
H
H
Lindstrom
J A
JA
Boslego
J W
JW
Warren
R A
RA
Van de Verg
L
L
Deal
C D
CD
McClain
J B
JB
Griffiss
J M
JM
D000293:Adolescent; D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood / Q000652:urine; D015153:Blotting, Western; D004797:Enzyme-Linked Immunosorbent Assay; D006069:Gonorrhea / Q000276:immunology* / Q000382:microbiology* / Q000652:urine; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007928:Lethal Dose 50; D008070:Lipopolysaccharides / Q000096:biosynthesis / Q000276:immunology; D008297:Male; D008875:Middle Aged; D009344:Neisseria gonorrhoeae / Q000254:growth & development / Q000276:immunology / Q000472:pathogenicity*; D012008:Recurrence; D014526:Urethritis / Q000276:immunology* / Q000382:microbiology* / Q000652:urine
D000907:Antibodies, Bacterial; D007074:Immunoglobulin G; D008070:Lipopolysaccharides