Protection of Mice against Infection by Staphylococcus Aureus

Mice immunised with an aggressin from cell walls of a virulent strain of Staphylococcus aureus were protected against the effects of a subcutaneous injection of the homologous strain and of a range of heterologous strains of Staph. aureus. Three subcutaneous injections of 50 μg DOCR at weekly intervals led to a significant reduction in the severity of the lesion, and 5 such injections conferred almost complete protection. The superficial lesion was abolished and the viable count at 24 hr considerably reduced. Aggressin from a number of strains that inhibited the exudation of oedema in normal mice did not do so in immunised mice. Immunisation with a similar cell-wall fraction from a non-virulent strain gave no protection against infection either with respect to the severity of the surface visible lesion, the count of viable staphylococci 24 hr after infection or the effect on the exudation of oedema fluid.