All issues > Volume 32(12); 1989

Original Article

J Korean Pediatr Soc. 1989;32(12):1650-1660. Published online December 31, 1989.

The Transfer of IgG-Subclasses From Mother to Fetus in the Korean Population.

Goo Sang Kim¹, Sang Il Lee², Ka Young Chang³, Kwang Ho Lee³

¹Department of Obstetrics & Gynecology, School of Medicine, Inha University
²Department of Pediatrics, School of Medicine, Inje University
³Department of Anatomy, School of Medicine, Seoul National University

Received: August 22, 1989;  Accepted: November 27, 1989.

Abstract

Normal IgG is now divided into four subclasses; IgGl, IgG2, IgG3 and IgG4. Each subclass has its unique characteristics. The different subclass compositions of antibodies are raised in humans against different immunogenic materials such as vaccinations or microoraganisms. All the IgG subclasses are reported to be transferable from mother to fetus through the placenta, but there have been some controversies in case of IgG2. For the delineation of the transplacental passage of IgG-subclasses in the Korean population, we studied the IgG-subclasses levels in paired maternal and cord sera. We also observed the transfer rate of each subclass in different gestational ages, sexes, and birth weights. A hundred and eight paired sera were collected at the time of delivery from the gestational ages ranging from 23 weeks to 44 weeks. Radial immunodiffusion kits (The Binding Site Ltd., Birmingham, England) were used for the measurement of IgG-subclasses serum levels. At 36 weeks of gestation, cord serum levels of IgGl and IgG3 reached the maternal serum levels, and their transplacental transferabilities were 103% and 101% on the average. 89% of the maternal IgG4 was transferred to the fetus at 37 weeks of gestation. The amount of trans placental passage of these three IgG-subclasses did not alter in the succeeding gestational ages, and the transplacental transfer rates reached 104%, 102% and 89% at term. However, only 61% of maternal IgG2 was transferred at 36 weeks of gestation and its transfer rate increased there-after to reach 73% at term. Therefore, the placenta may play a selective barrier for the passage of IgG2, and the transferability of each IgG-subclass is IgGl = IgG3 > IgG4 > IgG2. The sex and birth weight did not affect the transplacental passage of IgG-subclasses.

Keywords :IgG-subclass, Transplacental Immunity