Analysis in human neonates of defective antibody-dependent cellular cytotoxicity and natural killer cytotoxicity to herpes simplex virus-infected cells.

Human neonatal mononuclear cells (MCs) had low antibody-dependent cellular cytotoxicity (ADCC) compared with cells from adults in a chromium-release assay against Chang liver cells infected with herpes simplex virus (HSV). Polymorphonuclear leukocyte (PMNL) ADCC of neonates was similar to that of adults. In a single-cell agarose conjugation assay IgG antibody to HSV significantly increased conjugation by adult MCs, adult PMNLs, and cord blood PMNLs but not by cord blood MCs. Expression of the high-affinity IgG Fc receptor (FcR) assayed by erythrocyte-antibody rosetting revealed significant differences between adult MC FcR and cord blood FcR. There was no difference in PMNL FcR expression. Human interferon-alpha increased neonatal MC adhesion in the presence of IgG and FcR expression, but it had no effect on MC ADCC. Defective FcR expression and target cell adhesion may partly explain low neonatal MC ADCC. In addition, cord blood cells have a lytic or recycle, as well as an adherence, defect.