Mouse CD25 Antibodies (clones PC-615.3 and 7D4)

Recombinant murinized CD25 antibodies for in vivo use

InvivoGen provides two monoclonal antibodies (mAbs) that target the mouse IL-2R alpha chain (mCD25). They feature a murinized IgG2a constant region and the variable region of either "blocking" or "non-blocking" clones.

— Anti-mCD25-PC-mIgG2a derived from the previously described rat IgG1 clone PC-61.5.3, a "blocking" anti-mCD25 [1,2]

— Anti-mCD25-7D4-mIgG2a derived from the previously described rat IgM clone 7D4, a "non-blocking" anti-mCD25 [2,3]

CD25, in association with CD122 and CD132, forms the high-affinity cell-surface receptor for the IL-2 cytokine (IL-2R). CD25 is constitutively expressed at high levels by regulatory T (Treg) cells and only transiently at low levels by effector T (Teff) cells upon activation [4]. While Teff cell function is augmented by IL-2 signaling, Treg cells absolutely require this signal for survival.

More details

Using recombinant technology, the Fc region of InvivoGen's Anti-mCD25 antibodies has been replaced by a mouse IgG2a isotype in order to mediate strong intra-tumoral Treg depletion. Their variable regions remain different, recognizing distinct epitopes on the CD25 molecule, blocking or not the IL-2 binding.

​• The original rat IgG1 PC-61.5.3 mAb mediates in vivo Treg depletion through a single activatory FcγR,  FcγRIII, on phagocytes [1,5]. However, this function is hampered in a murine tumor microenvironment due to the local upregulation of the inhibitory FcγRIIb, displaying a similar affinity for rat IgG1 [5]. PC-61.5.3, when turned into mIgG2a mAb, mediates superior intra-tumoral Treg depletion as it binds multiple activatory FcγR (i.e. FcγRI, FcγRIII, and FcγRIV) [5]. The variable region of PC-61.5.3 blocks IL-2 binding to CD25 and thus inhibits IL-2 signaling [2,6].

​• The original rat IgM 7D4 mAb is a non-depleting antibody [3]. 7D4, when turned into mIgG2a mAb mediates in vivo depletion of Tregs, in an equivalent manner to PC-derived mIgG2a [6]. The variable region of 7D4 does not block IL-2 binding to CD25 and thus preserves IL-2 signaling [2,6]. This particular aspect has been highlighted as an important parameter to achieve strong antitumor responses in mouse models. Indeed, the data suggest that IL-2 availability after Treg depletion supports anti-tumor Teff cells [6].

InvivoGen's Anti-mCD25 mIgG2a antibodies can be used for in vivo evaluation of anti-tumor monotherapy or combination therapies (i.e. with immune-checkpoint antibodies, or dendritic-cell-based vaccines) in mouse models. Anti-mCD25-mIgG2a mAbs are provided in an InvivoFit™ grade, a high-quality standard specifically adapted to in vivo studies.

Key features:

• Anti-mCD25-PC-mIgG2a is a depleting and blocking antibody
• Anti-mCD25-7D4-mIgG2a is a depleting and non-blocking antibody
• 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-mCD25-mIgG2a mAbs are produced in Chinese hamster ovary (CHO) cells, purified by affinity chromatography with protein A, and their specific binding to mCD25 has been validated by ELISA (see Figures).

References:

1. Setiady Y. et al., 2009. In vivo depletion of CD4+FOXP3+ Treg cells by the PC61 anti-CD25 monoclonal antibody is mediated by FcgammaRIII+ phagocytes. Eur J Immunol. 40(3):780-786.
2. Moreau J.L et al., 1987. Monoclonal antibodies identify three epitope clusters on the mouse p55 subunit of the interleukin 2 receptor: relationship to the interleukin 2-binding site. Eur. J. Immunol. 17(7):929-935.
3. Malek T.R.. et al., 1983. Identification and initial characterization of a rat monoclonal antibody reactive with the murine interleukin 2 receptor-ligand complex. PNAS 80(18):5694.
4. Damoiseaux J., 2020. The IL-2 – IL-2 receptor pathway in health and disease: The role of the soluble IL-2 receptor. Clinical Immunol. 218:108515.
5. Arce Vargas F. et al., 2017. Fc-optimized anti-CD25 depletes tumor-infiltrating regulatory T cells and synergizes with PD-1 blockade to eradicate established tumors. Immunity. 46(4):577-586.
6. Solomon I. et al., 2020. CD25-Treg-depleting antibodies preserving IL-2 signaling on effector T cells enhance effector activation and antitumor immunity. Nat. Cancer 1(12):1153.
7. Ellis G.L & Riley J.L, 2020. How to kill Treg cells for immunotherapy. Nat. Cancer. 1(12):1134-1135.