• CD40 is primarily expressed on the surface of antigen-presenting cells, such as B cells and dendritic cells. Its ligand, CD40L, is predominantly expressed on the surface of activated T cells. The interaction between CD40 and CD40L is crucial in immune responses, particularly in B cell activation, antibody production, and the proliferation of inflammatory cells, such as macrophages and lymphocytes. This pathway plays a key role in orchestrating adaptive immunity and regulating immune responses to pathogens and tumors.
• The development of drugs targeting CD40/CD40L is primarily focused on monoclonal antibodies. Most antibody research focuses on CD40 agonists and antagonists. Agonists are mainly used in the treatment of tumors, while antagonists are being investigated for the treatment of conditions such as organ transplantation and autoimmune diseases.
• The genome of mouse Cd40 gene that encode extracellular domain was replaced by human CD40 in B-hCD40 mice(C).
• Human CD40 was detectable in B-hCD40 mice(C).
• This product is used for pharmacodynamics and safety evaluation of  tumors and autoimmune diseases.

Gene targeting strategy for B-hCD40 mice(C). The exons 2-7 of mouse Cd40 gene that encode extracellular domain were replaced by human counterparts in B-hCD40 mice(C). The genomic region of mouse Cd40 gene that encodes transmembrane domain and cytoplasmic portion was retained. The promoter, 5’UTR and 3’UTR region of the mouse gene were retained. The chimeric CD40 expression was driven by endogenous mouse Cd40 promoter, while mouse Cd40 gene transcription and translation will be disrupted.

Strain specific CD40 expression analysis in wild-type BALB/cCrSlcNifdc mice and homozygous humanized B-hCD40 mice(C) by flow cytometry. Splenocytes were collected from wild-type BALB/cCrSlcNifdc mice  and homozygous B-hCD40 mice(C). Protein expression was analyzed with anti-mouse CD40 antibody (Biolegend, 124609) and anti-human CD40 antibody (Biolegend, 334309) by flow cytometry. Mouse CD40 was only detectable in wild-type BALB/cCrSlcNifdc mice. Human CD40 was exclusively detectable in homozygous B-hCD40 mice(C), but not in wild-type BALB/cCrSlcNifdc mice.