Objective       To investigate whether IL-15 can efficiently correct the immunosuppression of mice with sepsis

and to improve the survive rate of mice with sepsis.      Methods       Pseudomonas aeruginosa was injected into C57 mice via the caudal vein to build a mouse model of sepsis. The mice with sepsis were divided into a control group (treated by physiological saline via i.p. injection)

a first treatment group (treat

ed by 0.5 μg IL-15 via i.p. injection)

and a second treatment group (treated by 1 μg IL-15 via i.p. injection). The survival time of the mice with sepsis was observed. The quantity of bacteria immobilized to the spleens of the mice with sepsis was calculated. The T cell content and NK cell content in mouse blood were analyzed. The expression level of IFN-γ in the peripheral blood of the mice was analyzed.      Results       The survival time of the mice with sepsis in the control group (1.9±0.9 d) was significantly shorter than those in the first and second treatment groups (3.8±3.9 d and 5.0±4.9 d). The quantity of bacteria immobilized to the spleens of the mice with sepsis in the control group [(29.8±3.2)×10

3

CFU/μg

]

was significantly larger than those in the first and second treatment groups [(15.4±2.9)×10

3

CFU/μg and (9.7±1.5)×10

3

CFU/μg

P0.01

]

. The T cell content and NK cell content in mouse blood of the control group [(58.63±6.25)% and (9.83±1.36)%

]

were significantly lower than those in the first treatment group [(65.32±10.36)% and (18.25±5.24)%

P0.01

]

and the second treatment group [(69.84±13.28)% and (20.96±5.78)%

P0.01

]

. The expression level of IFN-γ in the peripheral blood of the mice in the control group was significantly lower than those in the treatment groups (P0.01).      Conclusion     IL-15 can efficiently correct the immunosuppression of mice with sepsis and adequately activate their natural immune systems and adaptive immune systems

so as to improve the survival rate.