Synergistic protection of mouse erythrocytes by CD59a and DAF from induced complement activation and lysis.

(A-D) FACS analysis showing that CD59a (panels A,C) and DAF (panels B,D) are not present on the double-knockout mouse erythrocytes (panels C-D) but are present on wild-type mouse erythrocytes (panels A-B). Open areas indicate control staining with secondary antibodies only. (E) CD59a/DAF double-knockout mouse erythrocytes (open circles) were much more sensitive than CD59a knockout erythrocytes (filled circles) to antibody-induced complement lysis by MAC assembled from human C5b-7 and mouse C8/C9 (n = 3 mice for each group; P < .01 for all serum dilutions, Student t test). Experimental conditions were the same as in Figure 3A. (F) CD59a/DAF double-knockout mouse erythrocytes were much more sensitive than either DAF knockout or CD59a knockout mouse erythrocytes to antibody-induced complement lysis by rat complement (n = 4 for each group; P < .001 between double-knockout and DAF or CD59a knockout mice, Studentt test). Experimental conditions were the same as in Figure 3B. Lysis data are representative of 3 different experiments.