Interaction of toxin of Corynebacterium diphtheriae with phagocytes from susceptible and resistant species

The interaction of the toxin of Corynebacterium diphtheriae with leukocytes from sensitive and resistant animal species was examined by determining the ability of toxin to inhibit protein synthesis by several types of phagocytic cell. Small amounts of toxin (25 minimal lethal doses) impaired protein synthesis in both polymorphonuclear leukocytes and mononuclear cells from humans and guinea pigs, whereas large amounts (2,000 minimal lethal doses) were required for minimal inhibition of mouse phagocytes. Peritoneal macrophages from hyperimmunized guinea pigs exhibited the same high degree of sensitivity to diphtheria toxin as did those from unimmunized animals. Prolonged incubation with toxin resulted in a 75% reduction in phagocytosis of polystyrene latex spheres but had no effect on transport of the glucose analogue 2-deoxy-D-glucose by guinea pig macrophages. Thus phagocytic cells, although they are endowed with a high level of phagocytic cell appear to reflect the native resistance or sensitivity of the host species of origin.