Dilution assessment of cervicovaginal secretions obtained by vaginal washing for immunological assays

Abstract

Local immunological defense mechanisms in the cervicovaginal mucosa currently remain incompletely defined, especially from a quantitative point of view. Addition of an inert substance, lithium chloride (LiCl), into the washing buffer used to carry out the vaginal washing for collecting cervicovaginal secretions and measurement of its concentration with a flame absorption spectrophotometer, before and after the specimen is sampled, permits the quantification of the volume of cervicovaginal secretions collected and the approximation of the dilution factor of a soluble component introduced by the washing. Lithium, at a concentration of 10 mM, gives the best precision of measurement and has no effect on the results of the immunoassays. In a population of 27 nonpregnant women (age range, 18 to 45 years), the volume of cervicovaginal secretions collected by vaginal washing with 3 ml of LiCl-phosphate-buffered saline was 12% ؎ 3.2% (mean ؎ standard deviation) of the total volume and showed large interindividual variations (range, 5.6 to 18.8%); the mean dilution factor of a soluble component from the vaginal secretions was 9.9% ؎ 2.8% (range, 6.3 to 18.8%). According to the date of the menstrual cycle, the mean volume of collected cervicovaginal secretions was significantly increased in the luteal phase in comparison with the follicular phase; conversely, the mean dilution factor of a soluble component was more important in the follicular than in the luteal phase. These features strengthen the need to quantify accurately the dilution factor introduced by vaginal washing when studying cervicovaginal immunity.

Systemic and Secretory Humoral Immunity in the Normal Human Vaginal Tract

“…Vaginal fluids were collected from 30-40 year-old clinically and serologically healthy volunteers, by washing the vagina with 3 ml of PBS. The samples, corresponding to an approximately 10-fold dilution of the original secretions [15], were centrifuged to remove cells, debris, and insoluble mucus, prior to storage at -80°C. Three pools (VF-1, VF-2 and VF-3) were prepared by mixing in each 1 vol (0.5 ml) of six diflFerent vaginal fluids, collected during the follecular (VF-1, and VF-3) or the luteal (VF-2) phase of the menstrual cycle.…”

Decreased cervicovaginal production of both IgA1 and IgA2 subclasses in women with AIDS

“…Serum was sampled from all subjects. Cervicovaginal secretions were collected by vaginal washing with 3 ml PBS, providing a 1:10 dilution of native secretions [7]. This dilution factor was further taken into account for testing and calculations, Paired serum and cervicovaginai secretions were aliquoted and kept frozen at -30°C until processing.…”

Methods for Evaluation of Humoral Immune Responses in Human Genital Tract Secretions

“…This approach has been used for the measurement of Igs in cervicovaginal secretions obtained by vaginal lavage. 9 Collection and processing of female and male genital tract secretions These procedures have been described in great detail, including the purchase of supplies, buffers and protease inhibitors, as well as precautions and exclusion criteria for collection in our previous publication. 2,5,7,10 For the purpose of this brief review, we selected the most pertinent points that relate to the aims of this conference.…”