Anti-Human/Mouse GRP78 [Clone C38] — Purified in vivo PLATINUM™ Functional Grade

This monoclonal antibody is aseptically packaged and formulated in 0.01 M phosphate buffered saline (150 mM NaCl) PBS pH 7.2 - 7.4 with no carrier protein, potassium, calcium or preservatives added. Due to inherent biochemical properties of antibodies, certain products may be prone to precipitation over time. Precipitation may be removed by aseptic centrifugation and/or filtration.

Liquid

Functional grade preclinical antibodies are manufactured in an animal free facility using in vitro cell culture techniques and are purified by a multi-step process including the use of protein A or G to assure extremely low levels of endotoxins, leachable protein A or aggregates.

To protect mouse colonies from infection by pathogens and to assure that experimental preclinical data is not affected by such pathogens, all of Leinco’s Purified Functional PLATINUM ™ antibodies are tested and guaranteed to be negative for all pathogens in the IDEXX IMPACT I Mouse Profile.

Functional grade preclinical antibodies may be stored sterile as received at 2-8°C for up to one month. For longer term storage, aseptically aliquot in working volumes without diluting and store at ≤ -70°C. Avoid Repeated Freeze Thaw Cycles.

Research Use Only

2 – 8° C Wet Ice

C38 activity is directed against the C-terminal domain of human and mouse GRP78, also known as binding immunoglobulin protein/Heat shock protein family A (HSP70) member 5 (BiP/HSPA5).

GRP78 is a highly conserved member of the HSP70 family that acts as a chaperone within the endoplasmic reticulum to maintain ER protein folding capacity¹. Under normal physiological conditions, GRP78 regulates the balance between cancer cell survival and apoptosis by maintaining the endoplasmic reticulum stress sensors and ER-associated proapoptotic machineries. GRP78 is a stress-inducible, glucose-regulated protein that commonly shows aberrant activation in cancer.

In injured or malignant cells, GRP78 is actively translocated outside the ER where it functions as a signaling receptor at the cell surface and plays roles in proliferation, invasion, apoptosis, inflammation, and immunity¹. In cancer, GRP78 plays a protumorigenic role via a variety of ligands and cell surface anchored proteins and is involved in the regulation of PI3K-protein kinase B and ^α2‐macroglobulin signaling. Cell surface expression can be induced by hypoxia and chemotherapy. GRP78 is considered an attractive target for cancer immunotherapy because of its localization to the cell surface in multiple types of malignant cancers.

C38 was generated by immunizing five female Balb/c mice with full-length recombinant GRP78 protein². Splenocytes were harvested from the mouse with the highest titer as determined by ELISA using recombinant GRP78 as a capture antigen and were subsequently fused to P3X63Ag8.653 myeloma cells. The hybridoma producing C38 was selected by ELISA and the antibody binding properties were characterized. C38 does not cause apoptosis but does block the stimulation of Akt phosphorylation that is characteristic of ^α2‐macroglobulin binding to GRP78. Additionally, C38 binds to a conformational epitope at the 17 kDa C-terminal end of GRP78 that is not recognizable after reducing by SDS for PAGE separation. As such, C38 is not useful in Western blotting but is capable of binding in an ELISA and on-cell Western blot analysis. The potential to use C38 in cancer immunotherapy³ and to alleviate resistance to chemotherapy¹ is under investigation.

GRP78 localizes to the endoplasmic reticulum lumen but can also be found at the cell surface of injured or malignant cells.

PI3K/AKT signaling and interacts with ligands such as Kringle 5, vaspin, and peptides like Pep42 on cancer and endothelial cells

1 Gopal U, Pizzo SV. J Cell Physiol. 236(4):2352-2363. 2021.
2 de Ridder GG, Ray R, Pizzo SV. Melanoma Res. 22(3):225-235. 2012.
3 Mo L, Bachelder RE, Kennedy M, et al. Mol Cancer Ther. 14(3):747-756. 2015.