Gene targeting strategy for B-hCD55 mice. The full coding sequence of mouse Cd55 and Cd55b gene was replaced by human CD55 full coding region gene sequences and 3’UTR in B-hCD55 mice.

• Mouse Cd55 and Cd55b have 85% identity in the full coding region.

Strain specific CD55 expression analysis in wild-type C57BL/6 and homozygous B-hCD55 mice by flow cytometry. Splenocytes were collected from wild-type C57BL/6 (+/+) and homozygous B-hCD55 mice (H/H) (n=3, 8-week-old) and analyzed by flow cytometry with species-specific anti-CD55 antibody. mCD55 was detectable in T, B cells of wild-type mice. hCD55 was detectable in T, B cells of homozygous mice.

Strain specific CD55 expression analysis in wild-type C57BL/6 and homozygous B-hCD55 mice by flow cytometry. Splenocytes were collected from wild-type C57BL/6 (+/+) and homozygous B-hCD55 mice (H/H) (n=3, 8-week-old) and analyzed by flow cytometry with species-specific anti-CD55 antibody. mCD55 was detectable in NK and DCs of wild-type mice. hCD55 was detectable in NK and DCs of homozygous mice.

Strain specific CD55 expression analysis in wild-type C57BL/6 and homozygous B-hCD55 mice by flow cytometry. Splenocytes were collected from wild-type C57BL/6 (+/+) and homozygous B-hCD55 mice (H/H) (n=3, 8-week-old) and analyzed by flow cytometry with species-specific anti-CD55 antibody. mCD55 was detectable in monocytes and macrophages of wild-type mice. hCD55 was detectable in monocytes and macrophages of homozygous mice. 

Strain specific CD55 expression analysis in wild-type C57BL/6 and homozygous B-hCD55 mice by flow cytometry. Splenocytes were collected from wild-type C57BL/6 (+/+) and homozygous B-hCD55 mice (H/H) (n=3, 8-week-old) and analyzed by flow cytometry with species-specific anti-CD55 antibody. mCD55 was detectable in neutrophils of wild-type mice. hCD55 was detectable in neutrophils of homozygous mice. 

Frequency of leukocyte subpopulations in spleen by flow cytometry. Splenocytes were isolated from female wild-type C57BL/6JNifdc mice and homozygous B-hCD55 mice (n=3, 7-week-old). A. Flow cytometry analysis of the splenocytes was performed to assess the frequency of leukocyte subpopulations. B. Frequency of T cell subpopulations. Percentages of T cells, B cells, NK cells, dendritic cells, neutrophils, monocytes, macrophages, CD4+ T cells, CD8+ T cells and Tregs in B-hCD55 mice were similar to those in C57BL/6JNifdc mice, demonstrating that humanization of CD55 does not change the frequency or distribution of these cell types in spleen.