Immunoglobulin A response against Gardnerella vaginalis hemolysin and sialidase activity in bacterial vaginosis.
OBJECTIVE
The aim of this study was to investigate the correlation between the immunoglobulin A immune response to Gardnerella vaginalis hemolysin and sialidase activity in vaginal fluids from patients with bacterial vaginosis.


METHODS
Nonpregnant women who were examined at a gynecologic clinic, in an age range of 18 to 62 years, were enrolled. The study population comprised 131 healthy volunteers, 32 women with bacterial vaginosis that was positive for immunoglobulin A to Gardnerella vaginalis hemolysin, 40 women with bacterial vaginosis that was negative for immunoglobulin A to Gardnerella vaginalis hemolysin, and 19 women with Candida vaginitis. Bacterial vaginosis was diagnosed by clinical criteria and Gram stain.


RESULTS
Sialidase activity was present in 75% (54/72) of patients with bacterial vaginosis. Women having bacterial vaginosis and lacking a specific immunoglobulin A response had a significantly higher level of sialidase activity than patients who had an immune response against Gardnerella vaginalis hemolysin. Sialidase activity was detected in 87% (35/40) of the former subgroup of patients with bacterial vaginosis and in 59% (19/32) of women of the latter subgroup. No sialidase activity was measured in patients with candidiasis. Specificity of the assay for healthy controls was 95% (124/131 women without sialidase activity).


CONCLUSIONS
Sialidases produced by Prevotella bivia and other microorganisms present in the microflora of patients with bacterial vaginosis are very likely a virulence factor not only by destroying the mucins and enhancing adherence of bacteria but also by impairing a specific immunoglobulin A immune response against other virulence factors such as cytotoxin from Gardnerella vaginalis.
Cauci
S
S
Department of Biomedical Sciences and Technologies, School of Medicine, University of Udine, Italy.
Driussi
S
S
Monte
R
R
Lanzafame
P
P
Pitzus
E
E
Quadrifoglio
F
F
D000293:Adolescent; D000328:Adult; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006194:Gardnerella vaginalis / Q000276:immunology / Q000378:metabolism* / Q000472:pathogenicity; D006460:Hemolysin Proteins / Q000276:immunology*; D006801:Humans; D007070:Immunoglobulin A / Q000276:immunology*; D008875:Middle Aged; D009439:Neuraminidase / Q000378:metabolism*; D016585:Vaginosis, Bacterial / Q000276:immunology* / Q000378:metabolism*; D014774:Virulence
D006460:Hemolysin Proteins; D007070:Immunoglobulin A; D009439:Neuraminidase