Lethal and Dermonecrotic Activities of Clostridium perfringens Iota Toxin: Biological Activities Induced by Cooperation of Two Nonlinked Components

Abstract

The effect of separate injections of two components of Clostridium perfringens iota toxin, designated I_a and I_b components, on the biological activities of the toxin was investigated. The intravenous injection of one component within 120min after the injection of the other component killed mice. The activity of iota toxin was abolished by anti-I_a or anti-I_b antiserum. On the other hand, when I_b component was intravenously administered to mice given anti-I_a antiserum within 120min after the intravenous injection of I_a component, the lethal activity was completely neutralized, but when I_a component was injected into mice that were given anti-I_b antiserum over 5min after the injection of I_b component, the activity was not neutralized. The separate injections of I_a and I_b components in skin of guinea pigs indicated dermonecrosis at the injection site of I_b components, but not at the site of I_a components. Furthermore, when one component was intradermally injected in guinea pigs and then the other intraperitoneally, the dermonecrotic activity of the toxin was observed at the intradermal injection site of I_b component, but not at that of I_a component. From the data, it appears that the lethal and dermonecrotic activities of iota toxin are initiated by the binding of I_b component to specific sites on tissues.