Human cord blood monocytes: binding and ingesting capacity mediated by Fc and C3b receptors

Human cord blood monocytes have been compared to monocytes from adults. Our results show that unstimulated cord blood monocytes are as effective as monocytes from adults with regard to their binding and ingesting capacity mediated by Fc and C3b receptors. Furthermore, when stimulated with PMA (phorbol-myristate-acetate), the C3b receptor-mediated phagocytosis in cord blood monocytes was enhanced to the same extent as in monocytes from adults. These findings show that Fc and C3b receptor functions in human monocytes are fully developed at birth and cannot explain the increased susceptibility to infections seen in the neonate.