3.3　Lymphocyte Subset Analysis

Peripheral blood lymphocyte subsets were analyzed using monoclonal antibodies（Coulter Corporation，Hialeah，FL）and two-color flow cytometry，as previously described［13］.The subsets that were analyzed included helper/inducer T-cells（CD4+），suppressor/cytotoxic T-cells（CD8+），cytotoxic T-cells（CD8+CD57+）and natural killer cells（CD56+）.Blood samples were drawn every two months during the study，and lymphocyte subset analysis was performed within 24 h of blood drawing.(https://www.daowen.com)