Comparative phagocytosis of cadmium microcrystals by peripheral blood glass-adherent cells of newborn and healthy adults.

Microcrystals of cadmium, saturated with human serum albumin, were employed as a microassay for phagocytosis by glass-adherent blood cells. Using this assay, it was found that leukocytes of newborns possess significantly higher phagocytic activity and that a higher proportion of active phagocytic cells is present in newborns than in adults. In contrast, adult sera contain higher level of opsonins for cadmium microcrystals than cord sera. Heat inactivation and zymosan absorption of both adult and cord sera decreased significantly the opsonic power of sera, thus suggesting the participation of complement in opsonization of these particles.