Pharmacokinetic characteristic of B-NDG hB2M/HLA-A2.1 mice plus has no difference compared with B-NDG mice. B-NDG mice, B-NDG HLA-A2.1 mice, B-NDG hB2M/HLA-A2.1 mice plus were treated with YH001 (anti-human CTLA4 antibody) (n=4). Blood samples were collected at different time point for the PK assay. The results showed that the PK results of B-NDG hB2M/HLA-A2.1 mice plus group was similar to that in B-NDG mice, and the drug concentration of B-NDG HLA-A2.1 mice group could not be measured at the time point 4 days later. Results indicated that when compared with B-NDG HLA-A2.1 mice, the B-NDG hB2M/HLA-A2.1 mice plus can significantly extend the half-life of antibody drugs in mice.