Augmentation of ADCC in mice by microbial fractions

The effects of a multicomponent microbial vaccine on murine (BALB/c) splenocyte antibody-dependent cytotoxicity (ADCC) to chicken red blood cells were studied. The vaccine consisted of BCG cell wall skeleton (CWS), trehalose dimycolate, and mutant S. typhimurium endotoxin attached to mineral oil microdroplets, and was administered in a single intravenous dose. ADCC began to increase as early as 2 days following injection, was significant by 5 days, persisted for as long as 20 days, and was associated with splenic hypertrophy. Administration of the vaccine over a dose range of 1.5-15-150 μg demonstrated an increasing cytotoxic response with increasing dosage. The majority of cytotoxic activity was eliminated by passage of the effector cells through Sephadex G-10. Serial addition of each of the three components to the preparation and testing of each of the components separately revealed that no one component was responsible for the augmentation of the ADCC, but that the CWS probably made the least contribution. Subtraction of the oil from the whole vaccine preparation resulted in a modest but significant loss of augmenting activity.