Chemotactic and bactericidal capacities of human newborn monocytes.

We evaluated the chemotactic and bactericidal capacities of human cord blood monocytes, and the ability of cord lymphocytes and sera to generate chemotactic (LDCF) and opsonic factors for monocytes. Our results suggest that the intrinsic locomotive capacity, and the receptor system for LDCF, are adequately developed in the newborn monocyte. Moreover, newborn lymphocytes appear to produce adequate amounts of LDCF, capable of attracting adult monocytes. Poor chemotaxis was observed only when cord monocytes were exposed to supernatants of cord lymphocytes, which suggests that both contribute to this abnormal response. An inhibitory factor for which only cord monosensitivity of monocytes and strength of chemotactic factor between adults and newborns would explain these results. Bactericidal capactiy of cord monocytes against Escherichia coli K-12 opsonized by either cord or adult serum was comparable to that of adult monocytes.