Objective    To investigate the changes of immune state and the impact on immunological rejection elicited by abdominal cavity bacterial infection after DA-Lewis rat liver transplantation.      Methods    Orthotopic liver transplant model was established by modified Kamada two-cuff technique. The animals were divided randomly into Group 1

isotonic Na chloride injected into abdominal cavity 3 days after operation; Group 2

mixed Bacillus coli

liquid injected instead of saline; Group 3

immunosuppressive drug CsA administered routinely after operation (3 mg·kg

-1

·d

-1

). All the animals were sacrificed 7 days after infection. The blood and graft samples were collected for cell-subpopulation

mixed lymphocyte culture

IL-4

IFN-γ mRNA detection and histological evaluation.     Results    Seven days after infection

the lympholeukocyte population

CD4/CD8（G1=1.753±0.181，G2=1.384±0.073，G3=0.997±0.025）and lympholeukocyte function（SI：G1=67.59±3.40，G2=37.14±0.90，G3=15.87±0.51）declined in Group 2 as compared with other groups and cellular differentiation drifted to Th2. There was significant difference between Group 2 and Group 1 or 3.     Conclusion    Abdominal cavity bacterial infection after rat liver transplantation will promote the differentiation of T cells into Th2

down-regulate CD4/CD8 ratio and immune function of lymphocytes and accordingly alleviate partly the acute rejection following liver transplantation.