In utero immunosympathectomy of mice

Abstract

The antibody for mouse submaxillary gland nerve growth-promoting protein crosses the placenta when injected into pregnant mice and produces a partial immunosympathectomy in the fetus. A dose schedule of 300 units/g twice a day during the 11th to 16th or 12th to 17th day of gestation resulted in significant decreases in the tissue norepinephrine content of the spleen, submaxillary glands and heart (15.5, 25 and 39 per cent, respectively, of control values). Nonrepinephrine levels in other tissues (lungs, gastro-intestinal tract, kidneys and uterus) were not significantly decreased. Injection of the antiserum once a day (300 units/g) during the 13th to 18th day of gestation resulted in a less pronounced reduction in norepinephrine content of the spleen and submaxillary glands. Exposure of the fetus to the antibody during the 7th to 12th day of gestation produced less marked decreases of norepinephrine levels in the spleen and the heart, but no siignificant changes in the norepinephrine content of the submaxillary glands. The latter results could indicate that during the earlier stages of development the postganglionic sympathetic neurones are too immature to be affected, that regeneration or repair takes place or that the antibody does not readily cross the placenta. Cell counts of superior cervical ganglia showed that prenatal antiserum treatment decreased the cell population by approximately 50 per cent. Catecholamine levels in the brain and the adrenal medulla were not affected by the prenatal treatment with the antiserum.