Assessment of macrophage activity. Hatched bars represent the percentage of macrophages that incorporated at least one red cell. Tg6 macrophages incubated together with tg6 erythrocytes showed the highest phagocytotic activity followed by wt macrophages incubated with tg6 erythrocytes. Wt macrophages were less active compared with tg6 macrophages when coincubated with tg6 or wt erythrocytes, respectively. Tg6 erythrocytes were significantly more attractive than wt erythrocytes for both tg6 and wt macrophages. Moreover, the PKH26 fluorescent area of per single macrophage (open bars) was significantly larger in tg6 macrophages coincubated with tg6 erythrocytes compared with all other combinations of macrophages and erythrocytes. P values for hatched bars were calculated using a Fischer test, and for open bars using a 2-tailed Student t test for unpaired samples. Means ± SD of 4 independent experiments each; *P < .05.