Inhibition of chemokines binding to the DARC by the anti-Duffy MoAb, anti-Fy6. (A) Inhibition of specific ¹²⁵I-labeled IL-8 binding to Duffy-positive RBCs by increasing concentrations of anti-Fy6. The closed circles represent binding of ¹²⁵I-labeled IL-8 to cells expressing type A IL-8 receptor. Anti-Fy6 specifically inhibits binding of IL-8 to DARC in a dose-dependent fashion. (B) Inhibition of specific binding of radiolabeled IL-8, MGSA, MCP-1, and RANTES to Duffy-positive RBCs by anti-Fy6. Anti-Fy6 inhibits the binding of both C-X-C chemokines (IL-8, MGSA) and C-C chemokines (MCP-1, RANTES) to DARC. (Reprinted with permission from Science, Horuk R, Chitnis CE, Darbonne WC, Colby TJ, Rybicki A, Hadley TJ, Miller LH: A receptor for the malarial parasite Plasmodium vivax: The erythrocyte chemokine receptor. 261:1182, 1993. Copyright 1993 American Association for the Advancement of Science.)97