Immune checkpoint blockade therapies enhance antitumor immune responses and work effectively in particular cancers such as melanoma. The immune checkpoint therapies target receptors such as CTLA4 (cytotoxic T lymphocyte antigen-4) and PD-1(programmed death-1) on cytotoxic T-cells, and their respective ligands, such as PD-L1 and B7-1 (CD80), on tumor cells. Antibodies can inhibit binding of these receptor/ligand pairs, disrupt the signals for cytotoxic T-cells, and accelerate immune responses against cancer (1-6).
Investigating the effects of these therapeutic antibodies requires different types of rodent cancer models. In the studies, same-species antibodies must be used because administered heterogonous antibodies will be inactivated by the host's immune response. In fact, heterogonous antibodies only work for short-term animal studies such as melanoma models (2-6). Chondrex, Inc. provides mouse anti-mouse CTLA4 and PD-L1 antibodies which prevent the binding of their respective receptor and ligand. These antibodies are applicable to many types of mouse cancer models and are especially useful for long-term animal studies such as carcinoma models (7).
Antibodies for Melanoma Model
|Product||Catalog #||Price (USD)|
|Mouse Anti-Mouse CTLA4 IgG2a Monoclonal Antibody, Clone 2H9G9, 2 mg/ml x 5 ml||7133||499.00|
|Mouse Anti-Mouse PD-L1 IgG2b Monoclonal Antibody, Clone 3H9G2, 2 mg/ml x 5 ml||7134||499.00|
1. Efficacy of anti-immune check point antibodies in mouse melanoma models.
C57BL/6 mice received B16 melanoma cells (5 x 104 cells) intradermally on day 0, followed by intraperitoneal injections of 300 µg of monoclonal antibodies on days 3, 6, 9, and 12. Tumor sizes were evaluated every 3 days until day 27.
Figure 1. Melanoma Model Protocol
Chondrex, Inc.'s mouse anti-mouse immune checkpoint monoclonal antibodies (3H9G2: anti-PD-L1 and 2H9G9: anti-CTLA4) prevented 70% of melanoma tumor growth (Figure 2). More specifically, 90% of melanoma cell growth was inhibited in 3 out of 4 mice who received 2H9G9 and in 2 out of 4 mice who received 3H9G2 (Figure 3).
Figure 2. Effectiveness of Anti-Immune Checkpoint Antibodies in Melanoma Models
Figure 3. Melanoma Tumor Size in Individual Mice
2. Serological markers for evaluating cancer models and human patients
Cytokines and chemokines, such as TNF-alpha, IL-6, and CXCL1, regulate cancer cells as growth factors and play roles in metastasis (8-11). Chondrex, Inc provides ELISA kits to detect cytokines and chemokines in both mouse and human samples.
Tumor-immune cell crosstalk may play a role in metastasis of malignant cancer. Small membrane vesicles, exosomes, work to educate recipient cells by transporting miRNA, DNA, lipids, and cancer proteins, resulting in a proliferation of tumor cells, tumor niche remodeling, metastasis, and tumor-associated inflammation (11-15). To analyze the contribution of exosomes in cancer dynamics, especially metastasis, Chondrex, Inc. provides human exosome detection kits (CD9 expressing exosomes, CD63 expressing exosomes, and CD9xCD63 expressing exosomes). These kits can determine exosome concentrations in serum or culture media. Chondrex, Inc. now is working on developing exosome isolation kits using CD9 and CD63 as the tags(16).
4. Future Studies
Immune-checkpoint therapy can be adapted to treat infectious diseases such as sepsis (17-20) or viral infections. Indeed, adverse events of immune checkpoint therapy include symptoms of autoimmune diseases due to an overactivated immune response (23) Chondrex, Inc. provides autoimmune arthritis models such as collagen-induced arthritis (CIA), collagen antibody-induced arthritis (CAIA), adjuvant-induced arthritis (AIA), as well as antibody-induced nephritis, which are induced by activated immune responses. These animal models would benefit studies seeking to reduce or control the symptoms.