• Background: CD89, also referred to as Fc alpha receptor, is a high-affinity receptor for immunoglobulin A (IgA). It is primarily expressed on myeloid cells such as neutrophils, monocytes and macrophages. Upon binding to IgA or IgA immune complexes, CD89 initiates intracellular signaling cascades. It mediates phagocytosis, degranulation and production of reactive oxygen species and pro-inflammatory cytokines, thereby boosting innate immune defense against pathogens. Additionally, CD89 participates in immune homeostasis by regulating inflammatory responses..
• Targeting strategy: The full coding sequences of human CD89 gene that is driven by mouse CD11b promoter are inserted into mouse Gt(ROSA)26Sor locus in B-NDG hCD89.
• Validation: Human CD89 was detected in DCs, macrophages, monocytes, neutrophils from spleen, blood and bone marrow in homozygous B-DNG hCD89 mice. Humanization of CD89 does not change the overall frequency or distribution of immune cell types in spleen.
• Application: This model is employed to evaluate the efficacy of CD89-mediated cellular cytotoxicity

Gene targeting strategy for B-NDG hCD89 mice. The full coding sequences of human CD89 gene that is driven by mouse CD11b promoter are inserted into mouse Gt(ROSA)26Sor locus in B-NDG hCD89 mice.

Strain specific CD89 expression analysis in wild-type B-NDG mice and homozygous humanized B-NDG hCD89 mice by flow cytometry. Spleen were collected from wild-type B-NDG mice (+/+) and homozygous B-NDG hCD89 mice (H/H). Protein expression was analyzed with anti-human CD89 antibody (Biolegend, 354105) by flow cytometry. Human CD89 was exclusively detectable in homozygous B-NDG hCD89 mice, but not in wild-type B-NDG mice.

Strain specific CD89 expression analysis in wild-type B-NDG mice and homozygous humanized B-NDG hCD89 mice by flow cytometry. Spleen were collected from wild-type B-NDG mice (+/+) and homozygous B-NDG hCD89 mice (H/H). Protein expression was analyzed with anti-human CD89 antibody (Biolegend, 354105) by flow cytometry. Human CD89 was exclusively detectable in homozygous B-NDG hCD89 mice, but not in wild-type B-NDG mice.

Strain specific CD89 expression analysis in wild-type B-NDG mice and homozygous humanized B-NDG hCD89 mice by flow cytometry. Blood were collected from wild-type B-NDG mice (+/+) and homozygous B-NDG hCD89 mice (H/H). Protein expression was analyzed with anti-human CD89 antibody (Biolegend, 354105) by flow cytometry. Human CD89 was exclusively detectable in homozygous B-NDG hCD89 mice, but not in wild-type B-NDG mice.

Strain specific CD89 expression analysis in wild-type B-NDG mice and homozygous humanized B-NDG hCD89 mice by flow cytometry. Blood were collected from wild-type B-NDG mice (+/+) and homozygous B-NDG hCD89 mice (H/H). Protein expression was analyzed with anti-human CD89 antibody (Biolegend, 354105) by flow cytometry. Human CD89 was exclusively detectable in homozygous B-NDG hCD89 mice, but not in wild-type B-NDG mice.

Strain specific CD89 expression analysis in wild-type B-NDG mice and homozygous humanized B-NDG hCD89 mice by flow cytometry. BM were collected from wild-type B-NDG mice (+/+) and homozygous B-NDG hCD89 mice (H/H). Protein expression was analyzed with anti-human CD89 antibody (Biolegend, 354105) by flow cytometry. Human CD89 was exclusively detectable in homozygous B-NDG hCD89 mice, but not in wild-type B-NDG mice.

Strain specific CD89 expression analysis in wild-type B-NDG mice and homozygous humanized B-NDG hCD89 mice by flow cytometry. BM were collected from wild-type B-NDG mice (+/+) and homozygous B-NDG hCD89 mice (H/H). Protein expression was analyzed with anti-human CD89 antibody (Biolegend, 354105) by flow cytometry. Human CD89 was exclusively detectable in homozygous B-NDG hCD89 mice, but not in wild-type B-NDG mice.

Frequency of leukocyte subpopulations in spleen by flow cytometry. Splenocytes were isolated from B-NDG mice (+/+) and homozygous B-NDG hCD89 mice (male, 9-week-old, n=3). Flow cytometry analysis of the splenocytes was performed to assess the frequency of leukocyte subpopulations. Frequencies of T cells, B cells, NK cells, DCs, neutrophils, monocytes and macrophages in B-NDG mice were similar to those in B-NDG hCD89 mice, demonstrating that humanization of CD89 does not change the frequency or distribution of these cell types in spleen. Values are expressed as mean ± SEM. Significance was determined by two-way ANOVA test.  *P < 0.05, **P < 0.01, ***P < 0.001.