PROBLEM: This study demonstrated that the human embryo produces interferon-gamma (IFNγ). It is important to know whether IFNγ can be produced before implantation. Therefore the aim of this study was to evaluate the profile of IFNγ production between days 2 and 5 after in vitro fertilization.
METHOD: Twenty embryos were cultured from day 2 to 5 after fertilization. The embryo stages were checked each day and the media refreshed. IFNγ levels were estimated by an enzyme-linked immunosorbent assay.
RESULTS: All embryos produced measurable IFNγ at least for 1 day. Yields of IFNγ were: 0.46 ± 0.45 (n = 4) on day 2, 0.69 ± 0.52 (n = 19) on day 3, 0.73 ± 0.52 (n = 15) on day 4, 0.55 ± 0.32 (n = 11) IU/ml on day 5, respectively. There was no significant difference in the IFNγ production between in vitro culture days or between the developmental stages of embryos.
CONCLUSION: IFNγ is produced by all the embryos and seems to peak between days 3 and 4, which is just before implantation.