HUMAN PROTECTIN (CD59), AN 18-20-KD HOMOLOGOUS COMPLEMENT RESTRICTION FACTOR, DOES NOT RESTRICT PERFORIN-MEDIATED LYSIS

Human protectin (CD59) is an 18-20-kD membrane glycoprotein that restricts lysis of human erythrocytes and leukocytes by homologous complement. By directly incorporating protectin into membranes of heterologous cells we observed that protectin did not prevent perforin-mediated killing, whereas complement killing was effectively restricted. Further, no significant enhancement of cell-mediated killing or target killing by purified perforin was observed with anti-protectin antibodies. Thus, in contrast with complement lysis, restriction of lysis by protectin does not apply to cell-mediated killing. © 1990, Rockefeller University Press., All rights reserved.