Anti-mCD4

Anti-mCD4-mIgG2a InvivoFit™ is a mouse anti-mouse monoclonal antibody (mAb) featuring the variable region of the previously described anti-mCD4 GK1.5 clone [1]. Using recombinant technology, the original GK1.5 rat IgG2b constant region has been replaced with a murine IgG2a format which mediates potent cytotoxic functions [2].

CD4 is a transmembrane protein primarily expressed on most thymocytes, and highly expressed by the peripheral mature CD4+ T cell population, including T helper (Th) and regulatory T (Treg) cells [3]. Other immune cells, such as monocytes and macrophages also express CD4, albeit to 10- to 20-fold fewer levels compared to T cells [4].

The anti-mCD4 GK1.5 mAb is commonly used for in vivo depletion of the CD4+ T cell population to study the role of this T cell subset in various immune responses, including anti-pathogenic responses, auto-immunity, cancer, or transplantation [5]. Depending on the nature of the experiment, extended treatment schedules (up to several months) may be required. Upon repeated injection of a xenogeneic mAb, mice produce anti–species antibodies, causing the removal of the administered mAb from circulation, thereby considerably reducing treatment efficacy. Moreover, this immunogenicity can lead to fatal hypersensitivity reactions [5-7] which can be reduced by mAb murinization [8].

Key features of Anti-mCD4-mIgG2a InvivoFit™:

• Derives from the GK1.5 clone, rat IgG2b, κ
• Features the mIgG2a isotype (constant region)
• Guaranteed sterile, endotoxin level < 1 EU/mg
• Suitable for parental delivery in mice (azide-free)
• Low aggregation < 5%
• Produced in animal-free facilities and defined media

Anti-mCD4-mIgG2a InvivoFit™ is produced in Chinese hamster ovary (CHO) cells, purified by affinity chromatography with protein A, and provided in an InvivoFit™ grade, a high-quality standard specifically adapted to in vivo studies. The specific binding of this mAb to cell surface mCD4 and its in vivo depleting function have been confirmed (see Figures).

References:

1. Dialynas D.P. et al., 1983. Characterization of the murine antigenic determinant, designated L3T4a, recognized by monoclonal antibody GK1.5: expression of L3T4a by functional T cell clones appears to correlate primarily with class II MHC antigen-reactivity. Immunol Rev. 74:29-56
2. Nimmerjahn F. & Ravetch J.V., 2005. Divergent immunoglobulin g subclass activity through selective Fc receptor binding. Science. 310(5753):1510-2.
3. Zhu J. et al., 2010. Differentiation of effector CD4 T cell populations. Annual Rev Immunol. 28:445-489.
4. Collman R. et al., 1990. Macrophage-tropic strains of human immunodeficiency virus type 1 utilize the CD4 receptor. J Virol. 64(9):4468-76.
5. Laky K. & Kruisbeek A.M., 2016. In vivo depletion of T lymphocytes. Current Protocols Immunology. 4.1.1-4.1.9. doi: 10.1002/0471142735.im0401s113.
6. Mall C. et al., 2016. Repeated PD-1/PD-L1 monoclonal antibody administration induces fatal xenogenic hypersensitivity reactions in a murine model of breast cancer. Onco Immunol. 5(2):e1075114.
7. Murphy, J.T. et al., 2014. Anaphylaxis caused by repetitive doses of a GITR agonist monoclonal antibody in mice. Blood. 123(14):2172-2180.
8. Belmar N.A. et al., 2017. Murinization and H chain isotype matching of Anti-GITR antibody DTA-1 reduces immunogenicity-mediated anaphylaxis in C57BL/6 mice. J Immunol. 198:4502-4512.