About InVivoMAb anti-mouse/human osteopontin (SPP1) The 100D3 monoclonal antibody reacts with mouse and human osteopontin (OPN), also known as SPP1. Osteopontin is a secreted arginine-glycine-aspartic acid (RGD)-containing glycoprotein that was originally isolated from bone. Osteopontin has been found in kidney, vascular tissues, biological fluids, and various tumor tissues. Osteopontin interacts with integrins and CD44 and regulates diverse biological processes including bone development, immune responses, and oncogenesis. Osteopontin is elevated in human colorectal cancer and is thought to function as an immune checkpoint. The 100D3 antibody is a blocking antibody that has been shown to increase the efficacy of tumor-specific CTLs in killing colon tumor cells in vitro and suppress colon tumor growth in tumor-bearing mice in vivo. InVivoMAb anti-mouse/human osteopontin (SPP1) Specifications IsotypeMouse IgG2c, κ Recommended Isotype Control(s)InVivoMAb mouse IgG2c isotype control, anti-dengue virus Recommended Dilution BufferInVivoPure pH 7.0 Dilution Buffer ImmunogenRecombinant mouse OPN protein Reported Applicationsin vivo OPN neutralization in vitro OPN neutralization ELISA FormulationPBS, pH 7.0 Contains no stabilizers or preservatives Endotoxin<2EU/mg (<0.002EU/μg) Determined by LAL gel clotting assay Purity>95% Determined by SDS-PAGE Sterility0.2 μm filtration PurificationProtein A RRIDAB_2927509 Molecular Weight150 kDa StorageThe antibody solution should be stored at the stock concentration at 4°C. Do not freeze. Application ReferencesInVivoMAb anti-mouse/human osteopontin (SPP1) (CLONE: 100D3)Klement, J. D., et al (2021). "Osteopontin Blockade Immunotherapy Increases Cytotoxic T Lymphocyte Lytic Activity and Suppresses Colon Tumor Progression" Cancers (Basel) 13(5). PubMedHuman colorectal cancers are mostly microsatellite-stable with no response to anti-PD-1 blockade immunotherapy, necessitating the development of a new immunotherapy. Osteopontin (OPN) is elevated in human colorectal cancer and may function as an immune checkpoint. We aimed at elucidating the mechanism of action of OPN and determining the efficacy of OPN blockade immunotherapy in suppression of colon cancer. We report here that OPN is primarily expressed in tumor cells, myeloid cells, and innate lymphoid cells in human colorectal carcinoma. Spp1 knock out mice exhibit a high incidence and fast growth rate of carcinogen-induced tumors. Knocking out Spp1 in colon tumor cells increased tumor-specific CTL cytotoxicity in vitro and resulted in decreased tumor growth in vivo. The OPN protein level is elevated in the peripheral blood of tumor-bearing mice. We developed four OPN neutralization monoclonal antibodies based on their efficacy in blocking OPN inhibition of T cell activation. OPN clones 100D3 and 103D6 increased the efficacy of tumor-specific CTLs in killing colon tumor cells in vitro and suppressed colon tumor growth in tumor-bearing mice in vivo. Our data indicate that OPN blockade immunotherapy with 100D3 and 103D6 has great potential to be further developed for colorectal cancer immunotherapy and for rendering a colorectal cancer response to anti-PD-1 immunotherapy.
