[Influence of "clumping factor" from Staphylococcus aureus on phagocytosis (author's transl)]

In phagocytosis experiments the pathogenic significance of the "clumping factor" (CF) of Staphylococcus aureus was studied. CF-positive staphylococci were engulfed considerably less by leukocytes from rabbits and cattle than CF-negative staphylococci. Equally, the engulfment of staphylococcal skeletons (SSk) coupled with partially purified CF was significantly less than that of the SSk. The SSk had been prepared by extraction of staphylocci with formic acid. By this method the SSk were freed of all substances associated with staphyloccal virulence. Before coupling with CF the SSk were activated by cyanogen bromide. These in vitro-observations could be confirmed by the corresponding phagocytosis studies in experimental body cavities of rabbits. Thus, CF apparently interfered with the engulfment of the staphylococci by the leukocytes.