Analysis of immunosuppressive molecules associated with murine in vitro fertilized embryos.

Supernatants from mouse in vitro fertilized (IVF) oocyte cultures may suppress in vitro lymphocyte proliferation stimulated by concanavalin A (Sigma, St. Louis, MO). Supernatants conditioned by incubation with mouse epididymal sperm alone were even more inhibitory. Thin-layer chromatography suggested the polyamines spermine in sperm and spermine plus spermidine in IVF embryo supernatants were responsible. Putrescine was not suppressive. In vitro fertilized oocytes from old CBA/J-strain mice (greater than 20 weeks) that suffer age onset infertility lacked suppression and manifest cleavage arrest that could be partially reversed by adding spermine to the cultures. The failure of IVF oocytes to produce adequate quantities of polyamines could lead to failure of implantation due to division arrest. A possible in vivo role of polyamines as immunosuppressor factors is discussed.