Effects of recombinant immunotoxin hIL-2-LuffinP1 on lymphocyte proliferation in vitro / 解放军医学杂志

ABSTRACT

Objective To observe the biological activity of the recombinant immunotoxin hIL-2-LuffinP1 derived by gene engineering in vitro.Methods To observe the inhibitory effect on lymphocytes in vitro,the splenocytes isolated from C57 and BALB/c mice were used for mixed mouse lymphocyte response(MLR),and the lymphocyte proliferation was observed in vitro with BALB/c mice splenocytes stimulated by concanavalin A(ConA).Different concentrations of hIL-2-LuffinP1 was added into the reaction system,with LuffinP1 adopted as control.3H-TdR incorporation assay was used to detect the effects of hIL-2-LuffinP1 on lymphocyte proliferation,and its effects on CTLL-2 cells(IL-2 dependent cells) were also observed.The experiments consisted of six groups(PBS,IL-2,LuffinP1,LuffinP1+IL-2,hIL-2-LuffinP1 and hIL-2-LuffinP1+IL-2).CTLL-2 cells were cultured for 12h after being treated with different agents,and then the cells were stained by trypan blue to estimate the dead cells in every 100 cells.Results It was showed that CPM declined correspondingly to the gradually increased concentration of hIL-2-LuffinP1,and cell proliferation was inhibited obviously.The inhibition rate was up to 97% at the concentration of 10-6mmol/L of hIL-2-LuffinP1.The activity of inhibiting lymphocyte proliferation was proportional to the dosage.On the contrary,no obvious inhibition to lymphocyte proliferation was found in the control group treated with LuffinP1,the inhibition ratio only reached to 14% with the same concentration of hIL-2-LuffinP1.It was also found that,when hIL-2-LuffinP1 and LuffinP1 in different concentrations added to spleen cells stimulated by ConA,hIL-2-LuffinP1 still exhibited strong ability of inhibition on the splenocyte proliferation,while LuffinP1 has no obvious inhibiting effect on the lymphocyte proliferation in the two reaction systems mentioned above.MLR showed the same results.Furthermore,in the experiment of cytotoxic effects of IL-2-LuffinP1 on CTLL-2 cells,the inhibition rates of hIL-2-LuffinP1+IL-2 group and hIL-2-LuffinP1 group were 29.6% and 47.4% respectively,the difference was significant compared with IL-2 group(P