The Doha Declaration has entrusted to the members of WHO the right to use the compulsory licensing for drug patents in the face of global public health crises.Although the basic compulsory licensing system for drug patents has been established in China, the efficiency of its implementation is low, the responsibility of its executive departments is unclear, the related rules are not fully understood by pharmaceutical enterprises, it is thus necessary to improve and perfect the relevant legal provisions and systems in order to effectively improve the accessibility of drugs.

AIM: To investigate the details of CD4 + T cell polarized to Th1/Th2 in vitro . METHODS: After isolated the PBMCs and blood-plasma from adult human peripheral blood by Ficoll-Hypaque centrifugation, the PBMC culture procedure with or without the self-blood -plasma was applied to polarize T cells in vitro , these cells were polarized by PHA(20 mg/L),non-PHA respectively. The polarized rates of Th cell after 24 h,48 h,72 h were estimated respectively by flow cytometry following two-color immunofluorescent staining. RESULTS: CD4 +T cell would polarize to Th1/Th2 two subsets after self-cytokines and PHA activation in vitro . The polarized rates of T cell after cultured for 24 h,48 h and 72 h were (13.28%?1.59%)/(12.70%?1.65%),(17.19%?1.03%)/(17.50%?1.30%),(19.49%?2.87%)/(18.58%?1.49%) respectively, but the polarized rates of T cell were very low if without self-blood-plasma. The difference between them was significant. The ratios of Th1/Th2 cells were about 1. CONCLUSION: CD4 +T cell from adult human peripheral blood would polarize to Th1/Th2 two subsets in the presence of self-blood-plasma and PHA(20 mg/L) in vitro , and the cell number of Th1 and Th2 would be in balance.