Methods to artificially stimulate gestational immune tolerance toward a xeno-fetus consist of intercurrently introducing a thing of a regular allogeneic being pregnant. For example, embryos of the species Spanish ibex are aborted whilst inserted alone into the womb of a goat, but when added together with a goat embryo, they’ll expand to time period. This approach has additionally been used to grow panda fetuses in a cat, but the cat mother died of pneumonia earlier than she completed term. Also, murine embryos of Ryukyu mouse (Mus caroli) will live to tell the tale to term in the uterus of a house mouse (Mus musculus) best if enveloped in Mus musculus trophoblast cells. Goat fetuses have likewise been efficiently grown in sheep wombs by enveloping the goat internal mobile mass in sheep trophoblast. Such envelopment can be created with the aid of first keeping apart the internal cell mass of blastocysts of the species to be reproduced through immunosurgery, wherein the blastocyst is uncovered to antibodies toward that species. Because most effective the outer layer, this is, the trophoblastic cells, are exposed to the antibodies, simplest those cells might be destroyed by next publicity to supplement. The final inner cell mass may be injected right into a blastocele of the recipient species to accumulate its trophoblastic cells. It has been theorized that the allogeneic thing prevents the production of maternal lymphocytes and cytotoxic anti-fetal antibodies, but the mechanism stays uncertain.
On the opposite hand, immune suppression with ciclosporin has shown no impact for this reason. Pre-switch immunization with antigens from the species supplying the embryo has promoted extra rapid and uniform failure of the interspecies pregnancy in mice, but expanded survival in horse-donkey experiments.