Strain specific MSLN protein expression analysis in wild-type mice and B-hMSLN mice by western blotting. Mouse MSLN was detectable in heterozygous B-hMSLN mice (H/+) and wild-type mice (+/+). Human MSLN was detectable only in B-hMSLN mice (H/+).

Representative human MSLN expression in different tissues of B-hMSLN mice by IHC. Tissues were stained with antibodies specific for human MSLN (A-H) or anti-IgG antibody (I). Bladder, kidney, liver, heart, lung and testis of B-hMSLN mice show human MSLN positive. Human lung carcinoma as a positive control (G); Dog brain was a negative control (H); Mouse lung tissues from the wild-type C57BL/6 mice (I). Other tissues were got from homozygous B-hMSLN mice (A-F). Original magnification ×200. Abbreviations: IHC, immunohistochemistry.

Representative mesothelin expression in lung tissues of B-hMSLN mice by IHC. Tissues were stained with antibodies specific for human MSLN (A, B) or anti-Rabbit IgG antibody (C). Membranes show human MSLN positive in homozygous B-hMSLN mice. The data was obtained from a partner. Original magnification ×20. Abbreviations: IHC, immunohistochemistry.

Blood chemistry tests of B-hMSLN mice. Serum from the C57BL/6 and B-hMSLN mice (n=8, 7 week-old, female) was collected and analyzed for levels of indicators. The measurements of B-hMSLN mice were similar to that in C57BL/6 mice, indicating that humanization does not change the health of related tissues, such as liver. Values are expressed as mean ± SEM.

Complete blood count (CBC). Blood from female C57BL/6 and B-hMSLN mice (n=8, 7 week-old, female) was collected and analyzed for CBC. WBC, LY%, NE% and MO% were decreased in B-hMSLN mice compared to wild type C57BL/6 mice. Values are expressed as mean ± SEM.