PASSIVE-IMMUNIZATION WITH ANTISERUM TO A NONTOXIC ALPHA-TOXIN MUTANT FROM STAPHYLOCOCCUS-AUREUS IS PROTECTIVE IN A MURINE MODEL

A nonhemolytic, nonlethal variant of Staphylococcus aureus alpha-toxin constructed via oligonucleotide-directed mutagenesis and containing a single amino acid substitution (H-35 to L) was used to immunize a rab bit. The resulting antiserum was cross-reactive with wild-type alpha-t oxin and neutralized its hemolytic activity in vitro. Passive immuniza tion of mice,vith rabbit antiserum conferred protection against lethal challenge with wild-type alpha-toxin and against acute lethal challen ge with a high-alpha-toxin-producing S. aureus strain. H35L alpha-toxi n may be useful as a protective immunogen in S. aureus vaccine studies .