Sialic acid content and sialyltransferase activity in lymphocytes from neonates.

Venous blood from 24 healthy volunteers, 20-40 years old, and umbilical cord blood from 28 healthy full-term neonates, immediately after delivery, was used for the determination of lymphocyte sialic acid content and sialyltransferase activity. A significantly increased content of lymphocyte sialic acid and an increased sialyltransferase activity were observed in neonates as compared to adults. It is suggested that the increased sialic acid content of fetal lymphocytes may contribute to a possible masking effect of antigenic sites on fetal immunocompetent cells.