Purification of an antimicrobial peptide from rabbit aqueous humour.

PURPOSE

To identify an antimicrobial factor previously demonstrated in rabbit aqueous humour.

METHODS

Rabbit aqueous humour was fractionated by a multi-stage process involving anion-exchange and size-exclusion liquid chromatography. The antimicrobial effect of aqueous humour fractions upon Staphylococcus aureus were evaluated in an in vitro model. The components of aqueous humour fractions mediating an antimicrobial effect were investigated by SDS-PAGE.

RESULTS

A single peptide of molecular weight approximately 8 kDa was identified which mediated an antimicrobial effect upon Staphylococcus aureus. Attempts to identify the peptide have been unsuccessful.

CONCLUSIONS

Rabbit aqueous humour contains an unidentified peptide that mediates an antimicrobial effect upon Staphylococcus aureus. If such a peptide is present in human aqueous humour it may contribute to the apparent resistance to bacterial infection manifest in the anterior chamber.