Immunochemical studies on the specific agglutinogens of Staphylococcus aureus. I. Isolation and characterization of antigen h1.

The specific Staphylococcus aureus agglutinogen h1 has been purified and shown to be a protein with a molecular weight of about 95,000. Chemical analysis revealed all the common amino acids, except tyrosine and the sulphur-containing ones. The purified h1 antigen was strongly immunogenic in rabbits. The antiserum produced one precipitation line on double diffusion in agar against a suspension of bacteria. It also agglutinated bacteria of the h1-containing strains, as well as tanned sheep erythrocytes sensitized with h1, in high dilutions. Antibodies to other known staphylococcal antigens were not detected. The identity between h1 and Pillet's type 9 antigen was confirmed.