β Toxin of Clostridium welchii : Cytotoxic Effects Produced by the • on Guinea-Pig Monocytes

The cytopathic effects of Cl. welchii β toxin on guinea-pig monocytes in vitro have been studied using the uptake of eosin-Y^* as evidence of cell death.

The experiments show that these effects are due to antigen—antibody reaction probably on the cell surface, and that these reactions are not dependent on the presence of complement. Monocytes can be actively sensitized in vivo, and passively sensitized in vitro. The serum used to passively sensitize the monocytes need not possess a precipitating antitoxin titre.

Comparable experiments using an ovalbumin antigen—antibody system produced the same cytopathic effects on the monocytes as those which occurred in the β toxin—cellular system.