Estradiol regulation of the secretory immune system in the female reproductive tract: IgA in uterine and vaginal secretions of rats following portacaval anastomosis

Mucosa-associated epithelial chemokine/CCL28 expression in the uterus attracts CCR10+ IgA plasma cells following mucosal vaccination via estrogen control

Previous studies demonstrated cross talk between mucosal and reproductive organs during secretory IgA Ab induction. In this study, we aimed to clarify the underlying mechanisms of this cross talk. We found significantly higher titers of Ag-specific secretory IgA Ab in the vaginal wash after mucosal vaccination by both the intranasal (i.n.) and the intravaginal routes but not by the s.c. route. Interestingly, Ag-specific IgA Ab-secreting cells (ASCs) were found mainly in the uterus but not in the cervix and vaginal canal after i.n. vaccination. The fact that most Ag-specific IgA ASCs isolated from the uteri of vaccinated mice migrated toward mucosa-associated epithelial chemokine (MEC)/CCL28 suggests dominant expression of CCR10 on the IgA ASCs. Further, IgA ASCs in the uteri of vaccinated mice were reduced drastically in mice treated with neutralizing anti-MEC/CCL28 Ab. Most intriguingly, the female sex hormone estrogen directly regulated MEC/CCL28 expression and was augmented by i.n. vaccination with cholera toxin or stimulators for innate immunity. Further, blockage of estrogen function in the uterus by oral administration of the estrogen antagonist raloxifene significantly inhibited migration of Ag-specific IgA ASCs after i.n. vaccination with OVA plus cholera toxin. Taken together, these data strongly suggest that CCR10(+) IgA ASCs induced by mucosal vaccination via the i.n. route migrate into the uterus in a MEC/CCL28-dependent manner and that estrogen might have a crucial role in the protection against genital infection by regulating MEC/CCL28 expression in the uterus.

Factors associated with fluctuations in IgA and IgG levels at the cervix during the menstrual cycle

OBJECTIVE

The objective of this analysis was to describe patterns and determinants of cervical immunoglobulin A (IgA) and G (IgG) levels during the menstrual cycle.

METHODS

A total of 154 women who attended 3 visits coinciding with the follicular, periovulatory, and luteal phases of their menstrual cycle were studied. Cervical secretions were collected at each visit for determination of total IgA and IgG levels. Questionnaires administered at each visit inquired about demographic characteristics and behavioral practices.

RESULTS

Total IgA and IgG levels were higher among oral contraceptive (OC) users than among naturally cycling women (hereafter, "non-OC users"). IgA and IgG levels decreased at midcycle, particularly among non-OC users. After adjustment for phase of the current cycle, specimen weight, and detection of blood in the sample, report of a recent illness was associated with lower IgA and IgG levels and increased age with higher IgA and IgG levels among OC users and non-OC users. Increased lifetime number of pregnancies was associated with a higher IgA level among non-OC users and a higher IgG level among OC users. Change in immunoglobulin levels between visits was associated with sample weight and the presence of blood for both OC users and non-OC users.

CONCLUSIONS

Phase of the current menstrual cycle and OC use were significant determinants of cervical IgA and IgG levels. The impacts of endogenous and exogenous hormones on cervical immunoglobulin levels should be further investigated.

Paternal Antigen-Bearing Cells Transferred during Insemination Do Not Stimulate Anti-Paternal CD8+T Cells: Role of Estradiol in Locally Inhibiting CD8+T Cell Responses

Maternal immunological tolerance of the semiallogeneic fetus involves several overlapping mechanisms to balance maternal immunity and fetal development. Anti-paternal CD8+ T cells are suppressed during pregnancy in some but not all mouse models. Since semen has been shown to mediate immune modulation, we tested whether exposure to paternal Ag during insemination activated or tolerized anti-paternal CD8+ T cells. The uterine lumen of mated female mice contained male MHC I+ cells that stimulated effector, but not naive, CD8+ T cells ex vivo. Maternal MHC class I+ myeloid cells fluxed into the uterine lumen in response to mating and cross-presented male H-Y Ag to effector, but not naive, CD8+ T cells ex vivo. However, neither unprimed nor previously primed TCR-transgenic CD8+ T cells specific for either paternal MHC I or H-Y Ag proliferated in vivo after mating. These T cells subsequently responded normally to i.p. challenge, implicating ignorance rather than anergy as the main reason for the lack of response. CD8+ T cells responded to either peptide Ag or male cells delivered intravaginally in ovariectomized mice, but this response was inhibited by systemic estradiol (inducing an estrus-like state). Subcutaneous Ag induced responses in both cases. Allogeneic dendritic cells did not induce responses intravaginally even in ovariectomized mice in the absence of estradiol. These results suggest that inhibition of antiallogeneic responses is restricted both locally to the reproductive tract and temporally to the estrous phase of the menstrual cycle, potentially decreasing the risk of maternal immunization against paternal Ags during insemination.

Cervical secretory immunoglobulin A in adolescent girls

PURPOSE

To determine whether there are differences in levels of cervical secretory immunoglobulin A (sIgA) between adolescent girls in the secretory and proliferative phases of their menstrual cycle.

METHODS

Sexually active adolescent girls (n = 117) at health maintenance organization (HMO) based adolescent medical clinic were recruited into the study. In addition to demographic and clinical data, cervical specimens were collected for sIgA measurement and gonorrhea culture, urine for chlamydia ligase chain reaction, and blood for progesterone levels. Subjects were classified as being in the proliferative phase or secretory phase of the menstrual cycle on the basis of their progesterone levels.

RESULTS

The mean age of the subjects was 17.2 years old. There was no difference in the sIgA levels between those in the proliferative phase of their cycle (n = 45; mean sIgA level, 0.0055 mg/mL) and those in the secretory phase (n = 40; mean sIgA level, 0.0032 mg/mL) (p > .10).

CONCLUSIONS

The secretory phase of the menstrual cycle does not appear to be associated with higher levels of sIgA in adolescent girls. These results suggest that adolescents with anovulatory cycles, i.e., those who lack a secretory phase, may not be at increased risk for genital tract infections such as chlamydia or gonorrhea.

Hormonal regulation of the secretory IgA (sIgA) system: estradiol- and progesterone-induced changes in sIgA in parotid saliva along the menstrual cycle

The effect of estradiol (E2) and progesterone (P4) on the IgA system, both at the systemic and at the mucosal level, was studied in 10 healthy young adult Mexican women during two consecutive menstrual cycles (MC); the control group consisted of five young adult Mexican men. Eight matched samples of blood and parotid saliva were obtained, in which serum E2, P4, and IgA were quantified. Parotid saliva was obtained with Curby's device and sIgA was quantified by an ELISA method. The MC was divided into follicular phase (FP, days 1 to 16) and luteal phase (LP, days 17 to 30). Serum IgA showed slight fluctuations along the period of study, but they were not different between women and men. Irrespective of the phase of the MC, salivary sIgA was higher in women than in men (P < 0.01); sIgA was slightly but not significantly higher in the FP, as compared to the LP. The comparison of phases in each individual woman showed significantly higher levels in the FP (P < 0.01). The profile of sIgA in saliva observed in women resembled the pattern of serum E2 (r = 0.859, P < 0.05), suggesting a possible relation of E2 in the secretion of sIgA by the parotid gland.

Vaginal immunoglobulin A (IgA) levels in post-menopausal women: influence of oestriol therapy

The concentration of secretory immunoglobulin A (IgA) in the vaginal fluid of 20 untreated post-menopausal women (aged 75.4 +/- 1.4 years) was compared with the levels in a group of 20 post-menopausal women (aged 73.2 +/- 1.5 years) treated with oral oestriol (E3) (2 mg/day) and a further group of 20 healthy, non-pregnant, fertile women (aged 28.2 +/- 1.8 years). Secretory IgA was determined using a paper disc modification of the single radial immunodiffusion technique. The vaginal concentration of IgA in the untreated women was 41.5 +/- 5.7 mg/l, which was higher than that recorded in those treated with E3 (20.8 +/- 5.7 mg/l, P less than 0.05) and in the fertile women (16.4 +/- 3.7 mg/l, P less than 0.01). Epithelial cells predominated in the wet smear preparations obtained from the women who received E3 and the fertile women, while a predominance of leucocytes was observed in the untreated women. Lactobacilli were found more frequently in the vaginal flora of the women in the E3 group (P less than 0.001) and the fertile women (P less than 0.001) than the untreated group. Faecal-type bacteria were seen more frequently in the vaginal flora of the untreated women than the E3 group (P less than 0.01) or the fertile women (P less than 0.001). The possible implications of the present findings with regard to the individual variation in the intensity of symptoms experienced by women suffering from the oestrogen deficiency syndrome are discussed.

The effect of adjuvants on antibody titers in mouse vaginal fluid after intravaginal immunization

Intravaginal (ivag) immunization elicits secretory immune responses in the female reproductive tract, but little is known about the safety and effectiveness of adjuvants for such immunization. Mice were immunized intravaginally once daily for 5 days with large doses of horse ferritin combined with aluminum hydroxide (AH), muramyl dipeptide (MDP), monophosphoryl lipid A (MPL), dimethyl dioctadecyl ammonium bromide (DDA) or cholera toxin (CT). Titers of anti-ferritin IgA and IgG were measured in vaginal fluid by ELISA. The most effective adjuvant for ivag primary immunization was AH, while MPL was most effective for ivag boosting. None of the adjuvants caused a detectable tissue reaction in vaginal mucosa. Primary ivag immunization for 5 days with ferritin and AH followed by ivag boosting for 5 days with ferritin and MPL elicited higher IgA titers in vaginal fluid than systemic priming and boosting with ferritin and AH or systemic priming and ivag boosting with ferritin and MPL. Systemically immunized animals exhibited the highest IgG titers in vaginal fluid. The data indicate that adjuvants, particularly AH, can increase local immune responses to intravaginal immunization, but it should be noted that multiple applications of large doses of antigen were used and that this route of sensitization may be relatively inefficient.

Neuroimmunomodulation of in vivo anti-rotavirus humoral immune response

Neuropeptides and neurohormones (neurotransmitters) have been shown to modulate immune responses in vitro and in vivo. Since reproduction and lactation are regulated by neurohormones, we investigated whether neurohormones could enhance anti-rotavirus immunity in milk. Rotavirus-free mice were immunized orally with killed bovine rotavirus (BRV) and bred 6 weeks post-immunization. Post-whelping, each group of dams (ten mice/group) was given a single injection of prolactin (PRL), estrogen, PRL and estrogen or testosterone. The effects of neuropeptides, substance P (SP) and somatostatin (SS) on serum and lactogenic anti-rotavirus humoral immune responses were also investigated. The results revealed that in the groups given PRL or estrogen, anti-rotavirus antibody titers in milk and serum were enhanced. In contrast, testosterone had a negative effect on antibody titers. The administration of neuropeptide SP resulted in some enhancement of the lactogenic anti-rotavirus antibody titer at day 9 post-whelping whereas the opposite effect was observed following administration of SS. Prolactin given at 100 micrograms/mouse, on the day after whelping, gave optimum milk and serum antibody responses. Neurotransmitters potentiated immune responses to the weaker immunogenic proteins, VP4 and VP7 as well as to the strongly immunogenic VP6. In order to verify that the enhancement of anti-rotavirus antibody production was due to PRL and not to other factor(s), bromocriptine (BCR), a selective PRL inhibitor, was used as a control. Mice given BCR exhibited a drastic reduction in anti-rotavirus antibody in serum and milk. The role of neurotransmitters in the modulation of the lactogenic immune response and its significance in protection of neonates from enteric infections is discussed.

Expression of IgA and secretory component in the normal and in adenocarcinomas of Fallopian tube, endometrium and endocervix

The occurrence and localization of IgA and secretory components (SC) were examined in the normal and in adenocarcinomas of Fallopian tube, endometrium and endocervix. IgA-containing immunocytes were identified in the stroma of 90% of normal Fallopian tubes. It is suggested that the Fallopian tube may have an immunological function and may, together with the endocervix, constitute the local secretory immune system of the female genital tract. IgA and SC were frequently demonstrated in the cytoplasm and luminal secretion of adenocarcinomas of the endocervix, endometrium and Fallopian tube. This study has shown a decrease in immunoreactivity of SC among poorly differentiated adenocarcinomas but has failed to demonstrate any correlation between the expression of IgA and the degree of differentiation of the tumours. Secretory component appears, therefore, to be more useful than IgA as an indicator of secretory activity and differentiation of adenocarcinomas of the female genital tract.