The B2M Knockout T-47D Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population derived from the human breast ductal carcinoma cell line T-47D, designed to abolish expression of the beta-2 microglobulin (B2M) gene. This polyclonal pool results from a heterogeneous disruption of the B2M locus via CRISPR/Cas9-mediated gene disruption, generating a mixed population with B2M loss-of-function. The knockout cell product retains the luminal epithelial characteristics of the parental T-47D line while providing a robust model for investigating the functional consequences of B2M deficiency in an estrogen-responsive breast cancer context.
T-47D is a widely used model of hormone receptor-positive breast cancer, originally isolated from the pleural effusion of a patient with infiltrating ductal carcinoma. These cells express estrogen receptor alpha (ER??) and progesterone receptor (PR), making them responsive to estrogen stimulation. As an adherent epithelial cell line, T-47D is extensively characterized for studying luminal breast cancer biology, including hormone signaling, cell proliferation, and gene expression programs dependent on estrogen and progestin. The pleural effusion origin reflects a metastatic setting, thereby enhancing the relevance of this model for investigating advanced breast cancer mechanisms.
B2M encodes the invariant light chain of the major histocompatibility complex class I (MHC?I) heterodimer, forming a non-covalent complex with the MHC?I heavy chain (HLA?A, HLA?B, HLA?C) and peptide antigen. This complex assembly occurs in the endoplasmic reticulum with the assistance of chaperones calreticulin, tapasin, and ERp57, and depends on peptide loading via the transporter associated with antigen processing (TAP). Surface expression of MHC?I is essential for presenting endogenous antigens to CD8+ cytotoxic T lymphocytes; the T cell receptor (TCR) engages the peptide?CMHC?I complex, triggering downstream signaling through Lck and ZAP70. Expression of B2M is regulated by interferon?gamma (IFN???) signaling, which activates the transcription factors interferon regulatory factor 1 (IRF1) and NF???B, thereby upregulating MHC?I antigen presentation pathway components.
Disruption of B2M in T-47D cells eliminates beta-2 microglobulin protein, preventing proper MHC?I folding and abrogating cell surface expression of classical MHC?I molecules. This impairment renders the knockout cells invisible to CD8+ T cell recognition, modeling a key immune evasion strategy observed in many tumors. Concurrently, loss of MHC?I can relieve inhibitory signals to natural killer (NK) cells, potentially sensitizing B2M?deficient T-47D cells to NK cell-mediated cytotoxicity via missing-self recognition. The model thus enables investigation of the dual impact of MHC?I loss on adaptive and innate immune responses, particularly in a hormone receptor-positive breast cancer background.
The B2M Knockout T-47D Polyclonal Cells are suited for a range of immuno-oncology and antigen presentation studies. Researchers can use this model to assess CD8+ T cell cytotoxicity and NK cell degranulation by co-culture assays, quantify MHC?I surface expression by flow cytometry (e.g., staining for HLA?ABC), and confirm B2M disruption by western blot or RT?qPCR. The estrogen responsiveness of the parental line further allows examination of hormone signaling interplay with immune evasion. Typical applications include development of MHC?I-independent immunotherapies, investigation of IFN???-mediated MHC?I induction (monitoring phospho?STAT1), and analysis of tumor immune escape in luminal breast cancer. For additional product details or custom requirements, please contact Ascent Research.
