Immunogenicity and molecular characterisation of staphylococcal delta haemolysin

In rabbit antisera to staphylococcal delta haemolysin the haemolysin-neutralising activity was associated with the IgG fraction as well as with the alpha and beta lipoproteins. On an equal-weight basis, the neutralising capacity of specific antibody was not significantly greater than that of serum alpha or beta lipoproteins. Anti-alpha haemolysin was not detected in any of the anti-delta-haemolysin antisera. Amino-acid analysis of delta haemolysin showed that lysine, aspartic acid, threonine and isoleucine were the predominant amino acids present; histidine, arginine, proline, cysteine and tyrosine were absent. The molecular weight of delta-haemolysin in phosphate-buffered saline was approximately 210 000.