Mouse CD8 Antibody (clone YTS 169.4)

Recombinant murinized CD8α antibody for in vivo use

Anti-mCD8-mIgG2a InvivoFit™ is a murinized anti-mouse monoclonal antibody (mAb) featuring the variable region of the previously described anti-mCD8 YTS 169.4 clone [1]. Using recombinant technology, the original YTS 169.4 rat IgG2b constant region has been replaced with a murine IgG2a format which mediates potent cytotoxic functions [2].

CD8 is a transmembrane protein primarily expressed on most thymocytes and highly expressed by the peripheral mature CD8+ T cell population [3, 4]. Two isoforms CD8α (Lyt-2) and CD8β (Lyt-3) are usually co-expressed and form a CD8α/β heterodimer that plays a critical role in CD8+ T cell development and activation. Other immune cells, such as Natural Killer cells and subsets of dendritic cells also express CD8α [5]. 

The anti-mCD8 YTS 169.4 mAb is commonly used for in vivo depletion of the CD8+ T cell population to study its role in various immune responses, including in a viral or tumoral context [6-8]. 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 reducing its in vivo efficacy. Moreover, this immunogenicity can lead to fatal hypersensitivity reactions [9-10] which can be reduced by mAb murinization [11].
Anti-mCD8-mIgG2a is provided in an InvivoFit™ grade, a high-quality standard specifically adapted to in vivo studies.

Key features of Anti-mCD8-mIgG2a InvivoFit™:

• Derives from the YTS 169.4 clone, rat IgG2b, κ
• Features the mIgG2a isotype (constant region)
• Filter-sterilized (0.2 µm), 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-mCD8-mIgG2a InvivoFit™ is produced in Chinese hamster ovary (CHO) cells and purified by affinity chromatography with protein A. The specific binding of this mAb to cell surface mCD8α and its in vivo depleting function have been confirmed (see Figures).

References:

1. Cobbold S.P. et al., 1984. Therapy with monoclonal antibodies by elimination of T-cell subsets in vivo. Nature. 312:548-551.
2. Nimmerjahn F. & Ravetch J.V., 2005. Divergent immunoglobulin g subclass activity through selective Fc receptor binding. Science. 310(5753):1510-2.
3. Fung-Leung W.P. et al., 1991. CD8 is needed for development of cytotoxic T cells but not helper T cells. Cell. 65:443-449.
4. Janeway C.A. jr., 1992. The T Cell Receptor as a Multicomponent Signalling Machine: CD4/CD8 Coreceptors and CD45 in T Cell Activation. Annual Rev Immunol. 10:645-674.
5. Laky K. & Kruisbeek AM., 2016. In vivo depletion of T lymphocytes. Current Protocols Immunology. 4.1.1-4.1.9. doi: 10.1002/0471142735.im0401s113.
6. Greczemiel U. et al., 2020. LCMV-specific CD4 T cell-dependent polyclonal B-cell activation upon persistent viral infection is short lived and extrafollicular. Eur J Immunol. 50:396-403.
7. Menares E. et al., 2019. Tissue-resident memory CD8(+) T cells amplify anti-tumor immunity by triggering antigen spreading through dendritic cells. Nat Comm. 10:4401.
8. Vincent-Fabert C. et al., 2019. Reproducing indolent B-cell lymphoma transformation with T-cell immunosuppression in LMP1/CD40-expressing mice. Cell Mol Immunol 16:412–414.
9. 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.
10. Murphy, J.T. et al., 2014. Anaphylaxis caused by repetitive doses of a GITR agonist monoclonal antibody in mice. Blood. 123(14):2172-2180.
11. 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.