Objective To evaluate the expression and function activity of P-glycoprotein (P-gp) in human mononuclear cells (MNCs) in vitro transfected by multidrug resistance-1(MDR1) mRNA. Methods Two MDR1 cDNA vectors, pT7TS_MDR1 and pGEM5Zf(+)_MDR1, were constructed and transcripted in vitro. Vector pGEM5Zf(+)_MDR1 only contained the coding region of mdr1 cDNA, and pT7TS_MDR1 also included Xeponus β-globin 5’ and 3’ untranslated region. MNCs were prepared from peripheral blood of parvicellular lung cancer patient. The two human mdr1 mRNAs were then transferred into human MNCs in vitro by DOTAP. And the expression efficiency and pump function of P-gp were measured with flow cytometry. Results Expression of P-gp significantly elevated in both transferred cells compared with untransferred cells (P < 0.01). And pT7TS_MDR1 showed higher capability in elevating the expression of P-gp than pGEM5Zf(+)_MDR1 (P < 0.01). The P-gp function was elevated in both pT7TS_MDR1 and pGEM5Zf(+)_MDR1 groups. The survival ratio of MNCs in erythrocyte-lysis-solution (ELS, 86.07%) and lymphocyte-isolation-solution (LIS, 83.67%) had no significant difference. The CD34+ cells content of the MNCs used for transfection was 2.65% and 1.01% in ELS and LIS group, respectively (P < 0.01).Conclusions It is a feasible approach to improve P-gp expression in human MNCs by transfection of MDR-1 mRNA. And the ELS may be more suitable for purifing MNCs for mRNA transfection than LIS. Objective To evaluate the expression and function activity of P-glycoprotein (P-gp) in human mononuclear cells (MNCs) in vitro transfected by multidrug resistance-1 (MDR1) mRNA. Methods Two MDR1 cDNA vectors, pT7TS_MDR1 and pGEM5Zf (+) _ MDR1 , were constructed and transcripted in vitro. Vector pGEM5Zf (+) _ MDR1 only contained the coding region of mdr1 cDNA, and pT7TS_MDR1 also included Xeponus β-globin 5 ’and 3’ untranslated regions. MNCs were prepared from peripheral blood of parvicellular lung cancer patient . The expression of P-gp significantly elevated in both transfected cells compared with untransferred cells (P <0.01). The p-gp function was elevated in both pT7TS_MDR1 and pGEM5Zf (+) _ MDR1 groups. The sur The CD34 + cells content of the MNCs used for transfection was 2.65% and 1.01% in (LIS, 83.67%) had no significant difference. The vival ratio of MNCs in erythrocyte-lysis- ELS and LIS groups, respectively (P <0.01). Conclusions It is a feasible approach to improve P-gp expression in human MNCs by transfection of MDR-1 mRNA. And the ELS may be more suitable for purifing MNCs for mRNA transfection than LIS .