Antibodies raised against synthetic peptides from the Arg-Gly-Asp-containing region of the Leishmania surface protein gp63 cross-react with human C3 and interfere with gp63-mediated binding to macrophages.

The Leishmania surface glycoprotein gp63 binds to complement receptor type 3 on the macrophage surface. Antibody raised against a synthetic peptide containing the Arg-Gly-Asp region of the amino acid sequence of gp63 recognizes both gp63 and the alpha-chain of human C3. Monovalent Fab fragments from this antibody block gp63-mediated binding to macrophages.