RenMab™: Fully Human Antibody Mouse
The humanized mouse model is the preferred means to produce fully-human antibodies for therapeutics discovery. Mice that have endogenous antibody genes (heavy and light chains) replaced with human antibody genes can be used to develop humanized antibodies in just one step.
Biocytogen’s RenMab™ Mouse is an antibody-humanized mouse with the most complete antibody genes replacement in the world, which has been designed to greatly simplify and de-risk the antibody development process. In the RenMab™ Mouse, the parts of the genes that encode for antibody variable domains of H and κ chains are replaced in situ by human sequences using a unique chromosome engineering technique, while the constant domains and critical regulatory elements remain murine. The length and integrity of humanized antibody gene replacement in the RenMab™ Mouse significantly outperform other existing models. The RenMab™ Mouse has a normal immune system comparable to that of the wild-type mouse. Because of the higher diversity of its antibody genes, the RenMab™ Mouse has a higher potential for antibody drug development. The RenMab™ Mouse is the ideal platform for researchers to generate antibody-based drugs with strong specificity, high affinity, and diversity.
Features and Advantages
1. In situ gene replacement ensures that the antibody gene pattern of the RenMab™ Mouse is highly consistent with that of humans
The RenMab™ Mouse was designed and developed based on Biocytogen’s unique chromosome engineering technique. In this model, the parts of the genes that encode for antibody variable domains of heavy and κ light chains are replaced by human sequences.
H chain: The genes (about 2.6 Mb in length) that encode for murine antibody variable domains were replaced with the human variable domains (about 1 Mb in length, containing all human V/D/J antibody genes, Figure 1A).
κ light chain: Genes that encode for the variable domains of human κ light chain have two copies in opposite directions, namely proximal V cluster and distant V cluster. The coding region of the proximal V cluster is intact, which is frequently selected for antibody gene replacement in other humanized mouse models. Although the distant V cluster lacks the C gene and is considered to be a pseudogene, V and J genes are still potentially functional. We replaced the genes (about 3.2 Mb in length) that encode for murine antibody variable domains with the human variable domains (about 1.6 Mb in length) containing the two opposite-direction gene copies (Figure 1B).
Figure 1. Schematic of humanization in the RenMab™ mouse
2. Accurate humanization ensures that the RenMab™ Mouse has a completely developed immune system comparable to that of wild-type mouse
A complete analysis of the immune organs and tissues showed that the RenMab™ Mouse is highly comparable to the wild-type mouse. Our data has revealed that is no significant difference between the immune cells and immune tissues of RenMab™ Mouse and that of wild-type mouse.
3. The high diversity of antibody gene expression significantly boosts the abundance of antibody drug development
The RenMab™ Mouse expresses more diverse antibody molecules than other commercially available humanized mouse models. The components of different antibody isotypes in the serum of the RenMab™ Mouse are nearly the same as those of the wild-type mouse. The genes that encode for human antibody variable domains in the RenMab™ Mouse can be widely used, with a diversity of VDJ recombination. Taken together, the RenMab™ Mouse can produce a rich variety of therapeutic antibodies, which facilitates the development of antibody drugs.
- Body Weight and Spleen Weight Measurement No significant differences in average body weight and spleen weight were detected between RenMab™ Mouse and wild type mouse.
- Immune Cells ProfilingThe percentages of immune cells in spleen were analyzed by flow cytometry. In RenMab™ Mouse, the percentage of B cells,T cells, NK cells, CD4+ T cells and CD8+ T cells in spleen were identical to those of wild type mice.
- B Cell Development of RenMab™ Mouse IgM and IgD expression on B220+ splenocytes were analyzed by flow cytometry. Transitional type 1 (T1, B220+IgM+IgD-), Transitional type 2 (T2, B220+IgM+IgD+), Mature (M, B220+IgMlowIgD-) cell population.CD21 and CD23 expression on the surface of B220+ splenocytes were analyzed by flow cytometry. Marginal-zone (MZ, B220+CD21+CD23-) and Follicular (FO, B220+CD21LOWCD23+) B cells were quantitatively analyzed.No significant difference was observed between RenMab™ mouse and wild type mouse.
- Bone Marrow B Cell Development Analysis B cell progenitor cells in bone marrow were analyzed by flow cytometry. Base on expression levels of B220 and CD43, B cell progenitor cells in bone marrow can be divided into 3 cell populations, B220lowCD43highIgMlow(Pro-B-cell), B220lowCD43intIgMlow(Pre-B-cell), and B220highCD43lowIgMhigh(Immature-B-cell).B220lowIgM-IgD-CD138- (Plasma cell ), B220+IgM+IgD-CD38+ (Memory B cell ) in bone marrow or spleen were also analyzed by flow cytometry.No significant difference was observed between RenMab™ mouse and wild type mouse.
- Serum Ig Subtype AnalysisDifferent Ig subtypes in the serum of RenMab™ and WT mice were quantitatively measured by ELISA. No significant differences (n=6) in IgA, IgG1, IgG2b, IgG2c, IgG3 and IgM levels were observed.
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