The 7H11 monoclonal antibody reacts with mouse CLEC9A (C-type lectin domain family member 9A). CLEC9A, also known as DNGR1 (dendritic cell natural killer lectin group receptor 1) and CD370, is a type II transmembrane glycoprotein with a single extracellular C-type lectin domain. DNGR-1 is restricted in its expression, being found only on CD8α⁺, CD103⁺, CD11b⁻ subsets of DCs and plasmacytoid DCs. CLEC9A reportedly functions as an endocytic receptor for necrotic cells. It can mediate the cross-presentation of dead-cell associated antigens by dendritic cells in a Syk-dependent manner. It has been shown that targeting antigen to DNGR-1 on DC’s via coupling antigen to the 7H11 antibody can result in activation of antigen specific CD8⁺ T cell responses in vivo.

INVIVOMAB ANTI-MOUSE CLEC9A (CD370) (CLONE: 7H11)

Picco, G., et al. (2014). “Targeting DNGR-1 (CLEC9A) with antibody/MUC1 peptide conjugates as a vaccine for carcinomas.” Eur J Immunol 44(7): 1947-1955. PubMed

DCs are the most potent APCs and are the focus of many immunotherapeutic approaches for the treatment of cancer, although most of these approaches require the ex vivo generation and pulsing of DCs. We have targeted a subset of DCs in vivo using an Ab to DNGR-1, a C-type lectin dedicated to the cross-presentation of Ag expressed by subsets of DCs. HLA-A2 epitopes from the tumour-associated Ag, MUC1, were coupled to the anti-DNGR-1 Ab, and their efficacy in generating a Th1-cell response and inhibiting tumour growth was evaluated in a clinically relevant double transgenic mouse model expressing human MUC1 and A2K/b. Using this strategy, we demonstrate that an effective immune response to MUC1 can be generated, which results in a significant delay in the growth of MUC1-expressing tumours in both prophylactic and therapeutic settings. In addition, we also show, using PBMCs isolated from healthy volunteer blood, that target an MUC1 HLA-A2 epitope to human DNGR-1 in vitro can induce an MUC1-specific CD8(+) -T-cell response, which confirms the relevance of our in vivo murine results in the human setting.

Joffre, O. P., et al. (2010). “Efficient and versatile manipulation of the peripheral CD4+ T-cell compartment by antigen targeting to DNGR-1/CLEC9A.” Eur J Immunol 40(5): 1255-1265. PubMed

DC NK lectin group receptor-1 (DNGR-1, also known as CLEC9A) is a C-type lectin receptor expressed by mouse CD8alpha+ DC and by their putative equivalents in human. DNGR-1 senses necrosis and regulates CD8+ T-cell cross-priming to dead-cell-associated antigens. In addition, DNGR-1 is a target for selective in vivo delivery of antigens to DC and the induction of CD8+ T-cell and Ab responses. In this study, we evaluated whether DNGR-1 targeting can be additionally used to manipulate antigen-specific CD8+ T lymphocytes. Injection of small amounts of antigen-coupled anti-DNGR-1 mAb into mice promoted MHC class II antigen presentation selectively by CD8alpha+ DC. In the steady state, this was sufficient to induce proliferation of antigen-specific naive CD4+ T cells and to drive their differentiation into Foxp3+ regulatory lymphocytes. Co-administration of adjuvants prevented this induction of tolerance and promoted immunity. Notably, distinct adjuvants allowed qualitative modulation of CD4+ T-cell behavior: poly I:C induced a strong IL-12-independent Th1 response, whereas curdlan led to the priming of Th17 cells. Thus, antigen targeting to DNGR-1 is a versatile approach for inducing functionally distinct CD4+ T-cell responses. Given the restricted pattern of expression of DNGR-1 across species, this strategy could prove useful for developing immunotherapy protocols in humans.

Sancho, D., et al. (2008). “Tumor therapy in mice via antigen targeting to a novel, DC-restricted C-type lectin.” J Clin Invest 118(6): 2098-2110. PubMed

The mouse CD8alpha+ DC subset excels at cross-presentation of antigen, which can elicit robust CTL responses. A receptor allowing specific antigen targeting to this subset and its equivalent in humans would therefore be useful for the induction of antitumor CTLs. Here, we have characterized a C-type lectin of the NK cell receptor group that we named DC, NK lectin group receptor-1 (DNGR-1). DNGR-1 was found to be expressed in mice at high levels by CD8+ DCs and at low levels by plasmacytoid DCs but not by other hematopoietic cells. Human DNGR-1 was also restricted in expression to a small subset of blood DCs that bear similarities to mouse CD8alpha+ DCs. The selective expression pattern and observed endocytic activity of DNGR-1 suggested that it could be used for antigen targeting to DCs. Consistent with this notion, antigen epitopes covalently coupled to an antibody specific for mouse DNGR-1 were selectively cross-presented by CD8alpha+ DCs in vivo and, when given with adjuvants, induced potent CTL responses. When the antigens corresponded to tumor-expressed peptides, treatment with the antibody conjugate and adjuvant could prevent development or mediate eradication of B16 melanoma lung pseudometastases. We conclude that DNGR-1 is a novel, highly specific marker of mouse and human DC subsets that can be exploited for CTL cross-priming and tumor therapy.