• The hairless (Hr) gene encodes a transcriptional corepressor highly expressed in skin. In mice, multiple null and hypomorphic Hr alleles have been identified, which cause hairlessness in homozygous individuals, marked by alopecia arising following one cycle of near-normal hair growth.
• Gene targeting strategy: The Pmv43 was inserted into intron 7 of mouse Hr gene, which disrupted transcription and translation of mouse Hr gene.
• Functional analysis: Upon reaching adulthood, B-Hairless mice(C) are virtually hairless, with only a few sparse hairs scattered across their bodies.
• Leukocytes cell subpopulation analysis: The overall frequency and distribution of immune cell subsets in the spleen, blood, and lymph nodes were similar between B‑Hairless mice(C) and wild‑type BALB/cCrSlcNifdc mice.
• Application: B-Hairless mice(C) are immune-competent hairless mice, well suited for wound healing modeling, dermatological research, and safety and efficacy testing.

Gene targeting strategy for B-Hairless mice(C). The Pmv43 was inserted into intron 7 of mouse Hr gene, which disrupted transcription and translation of mouse Hr gene.

The photos of B-Hairless mice(C). B-Hairless mice(C) develop normal hair in their early life stages. As the mice grow, their hair starts to fall out from the face and is eventually shed completely across the body. Once reaching adulthood, they are nearly hairless or have only a small number of hairs remaining, as illustrated in the figure.

Frequency of leukocyte subpopulations in spleen by flow cytometry. Splenocytes were isolated from wild-type BALB/cCrSlcNifdc mice (female, n=3, 9-week-old) and homozygous B-Hairless mice(C) (female, n=3, 9-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, CD4+T cells, CD8+T cells and Tregs in B-Hairless mice(C) were similar to those in BALB/cCrSlcNifdc mice. Significance was determined by two-way ANOVA test.

Frequency of leukocyte subpopulations in blood by flow cytometry. Blood cells were isolated from wild-type BALB/cCrSlcNifdc mice (female, n=3, 9-week-old) and homozygous B-Hairless mice(C) (female, n=3, 9-week-old). A. Flow cytometry analysis of the blood cells 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, CD4+ T cells, CD8+ T cells and Tregs in B-Hairless mice(C) were similar to those in BALB/cCrSlcNifdc mice. Values are expressed as mean ± SEM. Significance was determined by two-way ANOVA test.

Frequency of leukocyte subpopulations in Lymph nodes by flow cytometry. Lymph nodes cells were isolated from wild-type BALB/cCrSlcNifdc mice (female, n=3, 9-week-old) and homozygous B-Hairless mice(C) (female, n=3, 9-week-old). A. Flow cytometry analysis of the lymph nodes cells was performed to assess the frequency of leukocyte subpopulations. B. Frequency of T cell subpopulations. Percentages of T cells, B cells, NK cells, CD4+T cells, CD8+T cells and Tregs in B-Hairless mice(C) were similar to those in BALB/cCrSlcNifdc mice. Significance was determined by two-way ANOVA test.