Dysbiosis in pregnant mice induced by transfer of human vaginal microbiota followed by reversal of pathological changes in the uterus and placenta via progesterone treatment.

OBJECTIVE: The vaginal microbiota dysbiosis induces inflammation in the uterus that triggers tissue damage and is associated with preterm birth. Progesterone is used to prevent labor in pregnant women at risk of preterm birth. However, the mechanism of action of progesterone still needs to be clarified. We aimed to show the immunomodulatory effect of progesterone on the inflammation of uterine tissue triggered by dysbiotic vaginal microbiota in a pregnant mouse model. METHODS: Healthy (n = 6) and dysbiotic (n = 7) vaginal microbiota samples isolated from pregnant women were transferred to control (n = 10) and dysbiotic (n = 14) pregnant mouse groups. The dysbiotic microbiota transferred group was treated with 1 mg progesterone (n = 7). Flow cytometry and immunohistochemistry analyses were used to evaluate inflammatory processes. Vaginal microbiota samples were analyzed by 16 S rRNA sequencing. RESULTS: Vaginal exposure to dysbiotic microbiota resulted in macrophage accumulation in the uterus and cellular damage in the placenta. Even though TNF and IL-6 elevations were not significant after dysbiotic microbiota transplantation, progesterone treatment decreased TNF and IL-6 expressions from 49.085 to 31.274% (p = 0.0313) and 29.279-21.216% (p = 0.0167), respectively. Besides, the macrophage density in the uterus was reduced, and less cellular damage in the placenta was observed. CONCLUSION: Analyzing the vaginal microbiota before or during pregnancy may support the decision for initiation of progesterone therapy. Our results also guide the development of new strategies for preventing preterm birth.

B Cell Subtypes in Individuals Received mRNA or Inactivated Vaccine Boosters After Fully Vaccinated with CoronaVac: A Longitudinal Study.

In this study, we aimed to investigate the changes in the B cell subpopulations after homologous or heterologous COVID-19 boosters. Blood samples were collected after baseline (3-5 months after two doses of CoronaVac), 1 and 3 months after BNT162b2 (n=28 and n=6), and CoronaVac (n=7 and n=4) boosters. Peripheral blood mononuclear cells (PBMCs) were isolated and stained with B cell markers, the ratios of naïve (CD19+CD20+CD27-), memory (CD19+CD20+CD27+), memory B cells expressing IgG (CD19+CD20+CD27+IgG+), and effector memory B cells (CD19+CD20+CD27+CD38+) were identified with flow cytometry. Significantly higher expression of memory B cells was observed in one month with BNT162b2 (12.16% one month, 5.98% three months) and CoronaVac (14.18% one month, 9.00% three months) boosters. IgG expressing memory B cell expression was significantly higher with BNT162b2 than with CoronaVac booster in one month (22.70% and 13.95%, respectively). The ratio of effector B cells in the first month after CoronaVac booster (25.44%) was significantly higher than the BNT162b2 booster (9.90%, p =0.0263).