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Related Experiment Video

Updated: Jun 3, 2026

Extraction, Labeling, and Purification of Lineage-Specific Cells from Human Antral Follicles

Extraction, Labeling, and Purification of Lineage-Specific Cells from Human Antral Follicles

Published on: November 30, 2022

Maturation of human ovarian follicles is accompanied by a decrease in the CD56+CD16+ natural killer cell population.

Ofer Fainaru¹, Shay Hantisteanu, Nechami Rotfarb

¹IVF Unit, Department of Obstetrics and Gynecology, Hillel Yaffe Medical Center, Hadera, Israel. ofainaru@techunix.technion.ac.il

Fertility and Sterility

|April 5, 2011

Summary

Proangiogenic natural killer (NK) cells are present in early ovarian follicles. Follicular maturation involves a decrease in cytotoxic NK cells, potentially impacting egg development.

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Published on: October 24, 2025

Area of Science:

Reproductive immunology
Cellular immunology
Ovarian biology

Background:

Natural killer (NK) cells, specifically CD56+CD16- subtypes, are found in follicular fluid (FF) and correlate with successful ovarian stimulation.
The presence and role of these NK cells in earlier stages of follicular development remain unclear.

Purpose of the Study:

To determine if "proangiogenic" CD56+CD16- NK cells are present in early-stage ovarian follicles.
To investigate the dynamics of NK cell populations (proangiogenic vs. cytotoxic) during follicular development.

Main Methods:

Observational study conducted in an academic in vitro fertilization (IVF) unit.
Follicular fluid (FF) was collected from patients undergoing in vitro maturation (IVM) or IVF.
Flow cytometry was used to quantify CD56+CD16- (proangiogenic) and CD56+CD16+ (cytotoxic) NK cells in FF.

Main Results:

"Proangiogenic" NK cells were found in antral follicles (IVM group) and showed a slightly higher abundance compared to mature follicles (IVF group).
Antral FF contained significantly higher concentrations of "cytotoxic" NK cells than FF from mature follicles.
A decrease in cytotoxic NK cells was observed as follicles matured.

Conclusions:

"Proangiogenic" NK cells are present in ovarian follicles from the antral stage onwards.
Follicular maturation is associated with a reduction in "cytotoxic" NK cells, which may negatively affect this process.