HBV infection is the key factor that causes liver inflammation,liver injury and immune dysfunction.Chronic hepatitis caused by HBV,a non-cytotoxic virus,is a kind of immune injury induced by liver cells that clear virus infection in immune system.Effector T lymphocyte plays a central role in immune system to clear HBV in liver cells,and the outcome of HBV infection is directly influenced by its functions and quantity.After antiviral therapy for patients with sustained HBV infection,whether to restore and rebuild immune function is critical in achieving ideal end point of treatment.Technologies,mainly including stimulation and culture of HBV antigen,flow cytometry,enzyme-linked immunoassay to detect cytokines,etc,are used in detection of HBV-specific T lymphocytes.