Effect of an arginine-glycine-aspartic acid-containing peptide on hematogenous candidal infections in rabbits

The adherence of Candida albicans yeast cells to the subendothelial extracellular matrix, fibronectin, laminin, and type I and IV collagen was tested. Fibronectin (10^-7 M) and a peptide, PepTite-2000 (Telios Pharmaceuticals Inc., San Diego, Calif.), containing the sequence arginine- glycine-aspartic acid (RGD) inhibited Candida adherence to these targets by greater than 90%. When C. albicans was perfused over ex vivo rabbit aortic endothelium, there was no significant difference in the amount of adherence in the presence or absence of the RGD-containing peptide. However, the RGD- containing peptide reduced the number of Candida organisms present in liver, brain, heart, and kidneys (P < 0.05) of rabbits 4 h after intravenous inoculation of 5 x 10⁷ C. albicans yeast cells. The peptide also reduced the number of macroscopic Candida abscesses in the kidneys of rabbits 72 h after intravenous inoculation of 10⁷ C. albicans yeast cells (P < 0.05). Inhibition of Candida adherence in vitro and in vivo may occur because the peptide blocks a fungal receptor that is necessary for adherence.