Objective:To compose the prokaryotic expression plasmid pGEX-6p-1/modified type TAT-VP3,and purify the modified fusion protein type of TAT-VP3 with the help of low temperature cultured inclusion body method;To explore the safety of modified type TAT-VP3 fusion protein,and the efficacy of modified fusion protein type of TAT-VP3 to immune system.Methods:Designed the modified type TAT gene and to synsthesized it by a biological company,then composed the prokaryotic expression plasmid pGEX-6p-1/modified type TAT-VP3,which was identified by enzyme cutting and gene sequence.Induced the expression of the modified fusion protein type of TAT-VP3 under low temperature, and collected the inclusion body to purify this fusion protein.The safety test and a series of immunopharmacological tests(the allergic test of modified fusion protein type of TAT-VP3 for injection in guinea pigs;rabbit pyrogen test;rabbit muscle stimulation test;the weight and index of immune organs;serum hemolysin test, lymphocyte transformation test of PHA stimulation;macrophage function test;serum complement test) were done to observe the safety of modified fusion protein type of TAT-VP3 and to evaluate the effects of this modified fusion protein type of TAT-VP3 on immune system.Results:We successfully composed the prokaryotic expression plasmid pGEX-6p-1/ modified type TAT-VP3,and purified the modified fusion protein type of TAT-VP3 with the low temperature cultured inclusion body method.There were no allergic reaction occurred;rabbit pyrogen test was qualified;there were no manifest abnormality occurred;the results of immunopharmacological test show that the weight and index of thymic were no manifest abnormality in low and high dosage treatment(P＞0.05),the weight of spleen has no significant difference in each group (P＞0.05),but the index of spleen in high dosage treatment was obvious difference with other group(P＜0.05);the OD value has no significant difference in each group (P＞0.05),but the OD value displaied a increasing tendency with increasing of TAT-VP3 dose;T lymphocyte transformation rate has no significant difference in each group (P＞0.05);the macrophage engulfing ability in low and high dosage treatment were higher than that of control group(P＜0.01,P＜0.05),the content of C3 and C4 in low and high dose group has significant difference with control group(P＜0.01).Conclusions:Composed the prokaryotic expression plasmid pGEX-6p-1/modified type TAT-VP3 successfully,induced and purified this modified fusion protein type of TAT-VP3 successfully.The allergic test is negative and qualification;pyrogen test is qualification,muscle stimulation test is qualification,modified fusion protein type of TAT-VP3 can enhance the humoral immunity function and nonspecific immunity in mice;increase the quantity of complement C3 and C4 in serum.There are not any adverse reaction that we found in immune system.