• Major Histocompatibility Complex Molecules(MHC) Includes two classes of MHC molecules involved in adaptive immunity, MHC I and MHC II. MHC I molecules are found on all nucleated cells; they present normal self-antigens as well as abnormal or non self pathogens to the effector T cells involved in cellular immunity. In contrast, MHC II molecules are only found on macrophages, dendritic cells, and B cells; they present abnormal or non self pathogen antigens for the initial activation of T cells.
• MHC class I molecules are expressed on all the nucleated cells and present peptides to CD8+T cells. MHC class II molecules present peptides to CD4+Tcells.
• B7-H3 may play a dual role in the immune system. On the one hand, B7-H3 acts as a co-stimulatory molecule that co-stimulates CD4+ and CD8+ cells, induces cellular immunity and selectively enhances interferon-γ (IFNG) production in response to T cell receptor signaling. On the other hand, B7-H3 also has a co-inhibitory effect, which inhibits Treg cells, thereby allowing tumors to escape the immune response. Antibodies targeting B7-H3 inhibit its immunosuppressive effects, suppressing and killing tumors.
• MHC I and MHC II were only detectable in spleen and blood of wild-type B-NDG mice, but not in homozygous B-NDG MHC I/II DKO/hB7-H3 mice.
• Human B7-H3 were detected in heart, liver, spleen, lung, skin, colon, stomach and brain in homozygous B-NDG MHC I/II DKO/hB7-H3 mice.
• This product is used for pharmacological and safety evaluation of drugs or cell therapies targeting B7-H3.

Gene targeting strategy for B-NDG MHC I/II DKO/hMSLN/hB7-H3 mice.

The murine B2m and H2-Ab1 gene were knocked out while a fused gene composed of murine B2m and Fcgrt gene was inserted after the signal peptide sequence of murine Fcgrt gene in B-NDG MHC I/II DKO/hMSLN/hB7-H3 mice.

The exons 3~4 of mouse Cd276 gene that encode the extracellular domain were replaced by human CD276 exons 3~6 in B-NDG MHC I/II DKO/hMSLN/hB7-H3 mice. The promoter, 5’ UTR and 3’UTR region of the mouse gene are retained. The human CD276 expression is driven by endogenous mouse Cd276 promoter, while mouse Cd276 gene transcription and translation will be disrupted.

Strain specific MHC I and MHC II expression analysis in homozygous B-NDG MHC I/II DKO/hB7-H3 mice by flow cytometry. Splenocytes were collected from wild-type B-NDG mice (+/+) and homozygous B-NDG MHC I/II DKO/hB7-H3 mice (Mut/Mut; H/H), analyzed by flow cytometry with species-specific anti-mouse H2-Kb/H2-Db antibody (Biolegend, 343906) and anti-mouse I-Ak antibody (Biolegend, 109908). MHC I and MHC II were only detectable in B-NDG mice, but not in homozygous B-NDG MHC I/II DKO/hB7-H3 mice.

Strain specific MHC I and MHC II expression analysis in homozygous B-NDG MHC I/II DKO/hB7-H3 mice by flow cytometry. Blood were collected from wild-type B-NDG mice (+/+) and homozygous B-NDG MHC I/II DKO/hB7-H3 mice (Mut/Mut; H/H), analyzed by flow cytometry with species-specific anti-mouse H2-Kb/H2-Db antibody (Biolegend, 343906) and anti-mouse I-Ak antibody (Biolegend, 109908). MHC I and MHC II were only detectable in B-NDG mice, but not in homozygous B-NDG MHC I/II DKO/hB7-H3 mice.

Western blot analysis of B7-H3 protein expression in homozygous B-NDG MHC I/II DKO/hB7-H3 mice. Various tissue lysates were collected from wild-type B-NDG mice (+/+) and homozygous B-NDG MHC I/II DKO/hB7H3 mice (Mut/Mut; H/H), and then analyzed by western blot with Anti-CD276 antibody (Abcam, ab219648). 40 μg total proteins were loaded for western blotting analysis. Human B7-H3 were detected in heart, liver, spleen, lung, skin, colon, stomach and brain in homozygous B-NDG MHC I/II DKO/hB7-H3 mice.