[A study of underlying immunoglobulin production by neonates]

During the prenatal period the ability of the fetus mononuclear cells (MNC) to produce antibodies is impaired. 1. In term infants, IgG production with only Staphylococcus aureus Cowan I strain (SAC) stimulation was significantly decreased (p less than 0.00005) as compared with adults. However, when adult MNC supernatant stimulated with Pokeweed mitogen (PWM-sup) was given to full term infants, antibody production significantly increased. 2. The activity inducing antibody production in the full term infant MNC is present primarily in the adult T cell culture supernatant. 3. B cell differentiation factor gamma (BCDF gamma) and BCDF mu, which induce IgG and IgM production, respectively, were significantly reduced in premature and full term infants (p less than 0.00005) as compared with adult. 4. By giving adult PWM-sup to the under 33-week-old infants MNC with SAC stimulation, the induction of both IgG and IgM was reduced, and IgG production was especially inadequate. From the above, it is thought that in full term infants, the production of BCDF gamma and BCDF mu which are produced by T cells is reduced compared to that of adults, and that this is mainly responsible for the reduced antibody production. In addition, in the under 33-week-old infants, the immaturity of B cells and inadequate BCDF production induce underlying poor or inadequate immunoglobulin production.