Strain specific CD79A expression analysis in wild-type C57BL/6N mice and homozygous humanized B-hCD79A mice by flow cytometry. Spleen was collected from wild-type C57BL/6N mice (+/+) (male, 8-week-old) and homozygous B-hCD79A mice (H/H) (male, 8-week-old). Protein expression in B cells was analyzed with anti-mouse CD79A antibody (Biolegend, 133105) and anti-human CD79A antibody (RD, FAB69201G) by flow cytometry. The anti-mouse CD79A antibody recognized both wild-type mice and humanized mice because its recognition sites were the intracellular region, which was not replaced in the humanized mice. Human CD79A was exclusively in homozygous B-hCD79A mice but not in wild-type C57BL/6N mice .

Mouse CD79B expression analysis in wild-type C57BL/6N mice and homozygous humanized B-hCD79A mice by flow cytometry. Spleen was collected from wild-type C57BL/6N mice (+/+) (male, 8-week-old) and homozygous B-hCD79A mice (H/H) (male, 8-week-old). Protein expression was analyzed with anti-mouse CD79B antibody (RD, FAB6814V) by flow cytometry. Mouse CD79B was both detectable in wild-type C57BL/6N mice and homozygous B-hCD79A mice.

Frequency of leukocyte subpopulations in spleen by flow cytometry. Splenocytes were isolated from wild-type C57BL/6N (+/+) and homozygous B-hCD79A (H/H) (female, n=3, 8-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, monocytes, macrophages, neutrophils, CD4+ T cells, CD8+ T cells and Tregs in B-hCD79A were similar to those in C57BL/6N mice, demonstrating that humanization of CD79A does not change the frequency or distribution of these cell types in spleen. The frequency of leukocyte subpopulations in blood and lymph nodes of B-hCD79A mice were also similar to wild-type C57BL/6N mice (Data not shown). Values are expressed as mean ± SEM. Significance was determined by two-way ANOVA test.  *P < 0.05, **P < 0.01, ***P <0.001.

Homozygotes for targeted null mutations exhibit arrested development of B cells at the pro-B cell stage, leading to loss of mature B cells. (MGI; DOI: 10.1016/j.cell.2004.05.014)