A method for monitoring antibodies against staphylococcal DNases

When small amounts of DNase produced by Staphylococcus aureus, S. intermedius or S. hyicus were added to Toluidine Blue DNA Agar (TDA), a medium for demonstration of staphylococcal antiDNases was produced. By applying this medium in microtitre plates, a test system for titration of staphylococcal antibodies in serum samples was developed. A colour change from blue to pink could be observed when the DNase was allowed to act, i.e. when no staphylococcal antiDNases were present in the samples. When serum with neutralizing antibodies were applied, no colour change developed. An end-point could easily be demonstrated in dilutions of the serum. A description of the method, including certain of its limitations is given.