HAEMOLYTIC COMPLEMENT ACTIVITY OF SERA OF FOETAL + NEW-BORN LAMBS

Abstract

Determination of the hemolytic complement titers of serum from 24 fetal lambs bled at 77 to 149 days gestation failed to reveal this activity earlier than 123 days. Titers near the end of the gestation period of 150 days were still very low. Among serum specimens collected from 17 newborn lambs before suckling, three were still without demonstrable complement activity. During the first week titers rose considerably in all of these lambs, were higher at three weeks but at ten weeks were still below the adult level. A number of fetuses had been injected with antigen mixtures at 50 to 111 days gestation and had responded with antibody development to one or more of these antigens. The rate of development of complement in these treated fetal lambs appeared similar to that in their untreated twin controls.