5TGM1 Syngeneic Model Service for Multiple Myeloma (MM)

The 5TGM1 syngeneic model service for multiple myeloma is an immune-competent C57BL/KaLwRij platform in which the Radl/Garrett-derived 5TGM1 myeloma cells home to the bone marrow and reproduce the clinical triad of human disease — a measurable serum paraprotein, severe osteolytic bone destruction, and marrow-confined tumor growth in a normal microenvironment. Alfa Cytology delivers this model as a complete preclinical capability — covering authenticated 5TGM1 / 5TGM1-GFP-luciferase expansion and banking, tail-vein inoculation into syngeneic or immunocompromised C57BL/6-background hosts, scheduled serum paraprotein quantification with in vivo imaging and skeletal radiography, and full myeloma histopathology with bone-turnover pharmacodynamics — all configured around each sponsor’s anti-myeloma agent, bone-directed therapy, or microenvironment hypothesis.

Overview of 5TGM1 Syngeneic Model for Multiple Myeloma (MM)

5TGM1 descends from one of the most instructive model systems in hematologic oncology: the Radl 5T series, in which aged C57BL/KaLwRij mice — an inbred strain that spontaneously develops benign idiopathic paraproteinemia, the murine analog of human MGUS, progressing to myeloma in roughly one percent of animals per year — yielded transplantable myelomas beginning with Radl’s reports in 1979 and 1988. From the aggressive 5T33MM tumor, Garrett and colleagues established 5TGM1 in 1997 by serial in vivo passage and subcloning, specifically to create a reproducible model of myeloma bone disease — and in doing so produced the only member of the 5T family (alongside 5T2MM and 5T33MM) that can be continuously cultured in vitro. The line secretes an IgG2bκ paraprotein that makes tumor burden measurable by weekly serum ELISA, homes intravenously infused cells predominantly to the bone marrow, and — critically — induces the pronounced osteolytic lesions that its 5T33MM parent lacks, making it the cost-effective workhorse of the 5T series. The host strain’s genetics have since been partially decoded: whole-genome sequencing revealed a Samsn1 deletion underlying KaLwRij’s myeloma predisposition, and 5TGM1 cells themselves are Samsn1-null, with re-expression shown to restrain their proliferation — one of the few model systems where the host strain’s susceptibility locus is molecularly defined.

Fig 1. Experimental schema and immune-mediated control of 5TGM1 cells in C57BL/6 versus KaLwRij mice: C57BL/6 recipients restrain bone marrow tumor growth through IFNγ-dependent mechanisms, whereas KaLwRij mice are fully permissive. (Kellermayer, Zoltán, et al., 2023)

In vivo, the model is disarmingly straightforward and faithful: a tail-vein infusion of 1 × 10⁶ cells into a six-week-old C57BL/KaLwRij mouse engrafts within about ten days, after which disease follows a compressed version of the human course — rising IgG2bκ paraprotein, progressive osteolysis visible on radiographs, hypercalcemia in a subset, renal involvement, hindlimb paralysis emerging at roughly four to five weeks, and death from marrow failure. One defining operational fact is documented clearly in the literature: 5TGM1 does not grow in conventional C57BL/6 mice, and the syngeneic system functions because KaLwRij’s unique background permits engraftment — a host restriction that also means the model cannot be casually crossed with standard transgenics, which is precisely why RAG-2-deficient C57BL/6 hosts (which do support 5TGM1 growth) were developed to enable genetic manipulation of the host microenvironment while preserving immunocompetence relative to SCID systems. The therapeutic record is correspondingly rich: the bisphosphonate ibandronate reduced vertebral and long-bone lesions; anti-sclerostin antibody preserved bone; bortezomib (PS-341) combined with the bone-seeking radiopharmaceutical 153-samarium-EDTMP showed synergistic anti-myeloma activity; and the model serves as an immune-competent benchmark for cyclic-peptide conjugates and antibody-drug conjugates. Reporter engineering — GFP and luciferase versions for calvarial and whole-body imaging — has added single-cell resolution of marrow homing and the endosteal dormancy niche. For sponsors, 5TGM1 offers the rare combination of immune competence, paraprotein quantification, genuine lytic bone disease, and a molecularly characterized host strain.

Cell Line Information: 5TGM1

The table below consolidates the key biological, cultural, and modeling characteristics of the 5TGM1 line, its reporter derivatives, and the defining features of its host strain.

Our Services

A model whose readout is a serum protein demands hematology-lab discipline, and Alfa Cytology runs 5TGM1 accordingly: authenticated banks of the parental and reporter lines, validated tail-vein inoculation into KaLwRij or RAG-2-deficient hosts with the documented host-restriction respected, weekly paraprotein ELISA with radiographic and imaging correlation, and endpoint pathology pairing marrow cytology with bone-turnover immunohistochemistry — all under one accountable preclinical operation.

Workflow of 5TGM1 Syngeneic Model Construction

Construction follows the Garrett/Radl methodology: 5TGM1 cells are expanded under authenticated conditions, infused intravenously into syngeneic or genetically permissive hosts, verified for engraftment, treated after a standardized establishment window, and analyzed with paraprotein, skeletal, and survival endpoints. The workflow comprises the following stages.

1. Cell authentication and banking: 5TGM1 or reporter derivatives are identity-verified, confirmed mycoplasma-negative, and expanded into low-passage working banks under the validated RPMI-1640-based formulation.
2. Cell harvest and formulation: Log-phase cultures are counted and viability-checked, then resuspended at 1 × 10⁶ cells in 100 μL of PBS per animal, with host strain (KaLwRij, or RAG-2-deficient C57BL/6 per the documented workaround) confirmed before allocation.
3. Anesthesia and intravenous infusion: Recipient mice are anesthetized with isoflurane, and cells are infused via the lateral tail vein using pre-warmed, controlled technique.
4. Engraftment verification and baseline sampling: Pre-treatment serum is collected approximately 10 days post-infusion to confirm baseline paraprotein; imaging-arm animals receive their first in vivo bioluminescence session at this checkpoint.
5. Randomization and treatment administration: Animals are randomized by paraprotein level or imaging burden; experimental arms — proteasome inhibitors, IMiDs, bisphosphonates, anti-sclerostin or RANKL-axis agents, skeletal radiotherapy, ADCs and conjugates, and combinations — proceed per study design with toxicity monitoring.
6. Longitudinal burden monitoring: Weekly serum IgG2bκ ELISA quantifies tumor burden; scheduled skeletal radiography and micro-CT track osteolytic lesion progression; imaging-arm sessions quantify whole-body kinetics; hindlimb paralysis and hunching are scored as morbidity markers.
7. Endpoint and histopathological analysis: Endpoints integrate survival, paraprotein kinetics, and lesion scores with histopathology (H&E of marrow, spine, and long bones confirming myelomatous infiltrates, plus CD138, Ki67, TRAP, and osteoblast/osteoclast immunohistochemistry for bone-turnover pharmacodynamics) and single-cell flow or imaging confirmation of marrow burden in reporter arms.

Fig 2. 5TGM1 Syngeneic Model construction workflow.

Case Study-5TGM1 Syngeneic Model Development

Alfa Cytology has conducted preclinical programs on the 5TGM1 platform spanning anti-myeloma agent evaluation, bone-directed therapy assessment, and marrow-microenvironment mechanism studies. In these studies, intravenously infused 5TGM1 tumors were longitudinally quantified by weekly paraprotein ELISA with radiographic and in vivo imaging correlation, treated per randomized regimens, and characterized at endpoint by histopathology with bone-turnover immunohistochemistry. Study-level datasets are available upon request.

Why Choose Alfa Cytology?

Alfa Cytology pairs myeloma-model operational experience with hematology-grade analytics, so every 5TGM1 study is executed with host-restriction discipline, paraprotein-quantified burden tracking, and skeletal pharmacodynamic reporting.

• Focused experience with the 5T series, including KaLwRij husbandry and the documented RAG-2-deficient C57BL/6 workaround for microenvironment-genetic designs.
• A single coordinated team managing cell banking, tail-vein infusion, weekly paraprotein ELISA, in vivo imaging, skeletal radiography, and endpoint pathology under one quality framework.
• Design fluency with proteasome/IMiD classes, bone-directed agents, skeletal radiotherapy, and ADC/conjugate formats.
• Endpoint panels pairing paraprotein kinetics and lesion scores with CD138/TRAP/osteoblast-osteoclast immunohistochemistry.
• Transparent milestone reporting and rapid scientific feedback throughout the engagement.

Contact Us

If your multiple myeloma program needs an immune-competent platform with a measurable paraprotein and genuine lytic bone disease — the clinical triad in miniature — Alfa Cytology is ready to build the study around your agent. Reach out to us with your regimen and endpoint requirements, or contact us today for a customized proposal and quotation for the 5TGM1 syngeneic model service.

For research use only. Not intended for any clinical use.