To investigate the effects of organ chlorine pesticide—endosulfan on erythrocyte immune functions in mice,in vivo and in vitro experiments were designed.A total of 40 mice were randomly divided into 4 groups in in vivo experiment.They were gavaged with endosulfan at levels of 0,0.4,1.6,and 6.4 mg/(kg·d)for 25 days,respectively.Blood was then collected to determine the immune functions of erythrocytes.In In vitro experiment,the erythrocytes from 9 mice were incubated with different concentrations of endosulfan:0(control),0(acetone,dissolvent),5,10,20,and 40 μg/ml,respectively.The immune adherent capacity of the erythrocyte was determined after culturing for 2 hours in vitro.In vivo experiment showed that the ratio of erythrocyte-C3b rosetting(C3bRR) significantly decreased,while the ratio of immune complexes rosetting(ICRR) increased with the increase of endosulfan dosage.There was no significant difference among the 4 groups in the activity of regulating NK cells by erythrocytes.The activity of regulating T cell adhering function by erythrocytes in 6.4 mg/(kg·d)group was significantly lower compared with other three groups.The activity of erythrocyte natural adhering enhancing factor in plasma remarkably reduced in 1.6 mg/(kg·d)group and 6.4 mg/(kg·d)group compared with that of the control group.The activity of erythrocyte natural adhering inhibitory factor decreased in 0.4 mg/(kg·d) group,but increased in 6.4 mg/(kg·d) group.In vitro,the C3bRR of erythrocytes declined,while the ICRR ascended with the increase of endosulfan concentration.These results suggest that endosulfan inhibits the erythrocyte immune adherent function and the positive regulating function of T cells by erythrocytes,and decreases the immune-enhancing activity of erythrocyte.The results also show that the effects of endosulfan on inhibitory factor activity are complicated:it inhibits the activity of inhibitory factor at the low dosage,while improves the activity of inhibitory factor at the high dosage.