Interferon-gamma production by the human preimplantation embryo

PROBLEM: This study demonstrated that the human embryo produces interferon-gamma (IFN gamma). It is important to know whether IFN gamma can be produced before implantation. Therefore the aim of this study was to evaluate the profile of IFN gamma 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. IFN gamma levels were estimated by an enzyme-linked immunosorbent assay. RESULTS: All embryos produced measurable IFN gamma at least for 1 day. Yields of IFN gamma 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 n as no significant difference in the IFN gamma production between in vitro culture days or between the developmental stages of embryos. CONCLUSION: IFN gamma is produced by all the embryos and seems to peak between days 3 and 4, which is just before implantation.