NEUTRALIZATION OF THE ACTIVITY OF A FASCIOLA-HEPATICA CATHEPSIN-L PROTEINASE BY ANTI-CATHEPSIN-L ANTIBODIES

Fasciola hepatica secretes a cathepsin L proteinase that is suggested to play an in vivo role in immunoprotection since the enzyme can cleav e host immunoglobulin. In the present report, rabbit anti-cathepsin L IgG was shown to bind to the cathepsin L enzyme and inhibit its abilit y io cleave IgG molecules. Cathepsin L can prevent the antibody-mediat ed attachment of eosinophils to newly excysted juveniles in in vitro a ssays; however, if anti-cathepsin L IgG are mixed with the cathepsin L prior to the addition of the enzyme to the assay, eosinophils attach to the newly excysted juveniles. Thus it is possible to prepare antibo dies that can bind and disrupt the biological activity of the F. hepat ica cathepsin L.