CT51 Syngeneic Model Overview
The CT51 syngeneic model is a murine colon carcinoma system derived from a chemically induced tumor in BALB/c mice. Closely related to the CT26 model family, CT51 displays a moderately immunogenic phenotype with robust primary tumor growth and reproducible responsiveness to immune checkpoint inhibition. It has become an important tool for preclinical evaluation of immunotherapies targeting colorectal cancer, particularly in studies emphasizing T-cell–mediated immunity, cytokine modulation, and combination therapeutic strategies.
When implanted subcutaneously or orthotopically into the colon of BALB/c mice, CT51 cells form well-vascularized, moderately differentiated tumors that mirror the morphological and molecular features of human colorectal carcinoma. The model’s intermediate growth kinetics and controlled metastatic potential allow for detailed analysis of both local tumor progression and systemic immune activation. Because CT51 maintains a functional immune microenvironment, it is ideally suited for mechanistic studies investigating the interplay between tumor cells, effector lymphocytes, and the tumor stroma under therapeutic modulation.
Request a Custom Quote for CT51 Syngeneic ModelBiological and Molecular Characteristics
The CT51 cell line originates from a BALB/c mouse treated with the carcinogen N-nitroso-N-methylurethane, which induces spontaneous colon carcinoma formation. It exhibits epithelial morphology and expresses markers consistent with undifferentiated or poorly differentiated adenocarcinoma. Similar to CT26.WT, CT51 tumors are triple-negative for ER, PR, and HER2 and demonstrate a high mutational burden that contributes to their immunogenic character. The tumor microenvironment is composed of a dense infiltrate of macrophages, T cells, and dendritic cells, reflecting a dynamic balance between immune activation and suppression.
Cytokine profiling of CT51 tumors reveals expression of IL-6, IFN-γ, and GM-CSF, which promote immune cell recruitment and macrophage activation. The tumor cells also produce VEGF and CXCL1, driving angiogenesis and inflammatory signaling. The combination of strong antigenicity and moderate immune suppression makes CT51 a reliable system for exploring therapeutic mechanisms that modulate immune balance and tumor immune escape.
| Parameter | Description |
|---|---|
| Host strain | BALB/c (female, 6–8 weeks) |
| Tumor origin | Chemically induced colon carcinoma (mouse) |
| Histological type | Moderately differentiated adenocarcinoma |
| Inoculation route | Subcutaneous, orthotopic (cecal wall), or intravenous |
| Tumor take rate | >95% |
| Doubling time | Approximately 3–4 days in vivo |
| Metastatic potential | Moderate; lung and liver metastases possible |
| Immunophenotype | Immunogenic with balanced T-cell and myeloid infiltration |
| Common applications | Immunotherapy, checkpoint blockade, vaccine and cytokine studies |
In Vivo Model Development and Tumorigenicity
In vivo establishment of the CT51 syngeneic model is achieved through subcutaneous or orthotopic implantation of viable tumor cells into immunocompetent BALB/c mice. Subcutaneous implantation produces rapidly growing, measurable tumors within 5–7 days post-inoculation, while orthotopic implantation in the cecum provides a physiologically relevant model of colorectal carcinoma with the potential for limited metastasis to regional lymph nodes or the liver. Intravenous injection is occasionally used for experimental metastasis studies.
Tumor growth is predictable and highly reproducible, enabling systematic evaluation of therapeutic response and immune modulation. The model’s moderate aggressiveness allows for longer observation windows, supporting studies of adaptive immune dynamics and treatment-induced immunologic memory. Because of its reproducible tumor take rate and stable immune infiltration, CT51 is frequently employed in studies assessing checkpoint inhibitors, adoptive T-cell therapies, and cytokine-based immunomodulatory approaches.
Request a Custom Quote for CT51 Syngeneic ModelHistopathology and Immunohistochemical Profile
Histological analysis of CT51 tumors reveals poorly to moderately differentiated epithelial cells forming irregular glandular structures. The tumors display dense cellularity, high mitotic index, and moderate necrosis, with a fibrous stroma infiltrated by macrophages, lymphocytes, and neutrophils. The vascular network is well developed, contributing to uniform perfusion and drug delivery during in vivo studies.
Immunohistochemical staining demonstrates high Ki-67 expression, consistent with rapid proliferative activity. CD3 and CD8 staining confirm extensive T-cell infiltration, particularly at the invasive margins. F4/80 and CD11b staining indicate significant macrophage and myeloid cell recruitment, while PD-L1 expression is typically moderate and inducible by interferon signaling. The immune landscape of CT51 tumors reflects a partially inflamed phenotype, suitable for evaluating therapies that enhance immune cell activation or overcome local immunosuppression. The combined histological and immunohistochemical features make CT51 a strong model for translational colorectal cancer research.
Preclinical Applications and Drug Response
The CT51 syngeneic model is a versatile platform for preclinical evaluation of immunotherapies and combination regimens targeting colorectal cancer. It has been widely applied in studies examining immune checkpoint blockade, cancer vaccination, cytokine therapy, and oncolytic viral treatments. Checkpoint inhibitors such as anti–PD-1 and anti–CTLA-4 have demonstrated measurable efficacy, characterized by reduced tumor growth and increased CD8⁺ T-cell infiltration. Combination approaches incorporating cytokine agonists, such as IL-2 or IL-12, or cytotoxic agents that induce immunogenic cell death, have further enhanced tumor regression and immune memory formation.
Because CT51 tumors maintain consistent immunogenicity and exhibit responsiveness to both innate and adaptive immune modulation, the model is often selected for mechanistic research into tumor immune escape and resistance. Its reproducible growth pattern and compatibility with immunocompetent BALB/c hosts make CT51 a valuable system for optimizing novel therapeutic interventions, studying antigen-specific immune activation, and modeling the tumor microenvironment under immune pressure.
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To request the CT51 syngeneic model for your preclinical studies, please use the form below. A customized quote and additional model specifications will be provided upon inquiry.
Request a Custom Quote for CT51 Syngeneic Model