5T33 Syngeneic Model Service for Multiple Myeloma (MM)

The 5T33 syngeneic model of multiple myeloma propagates a spontaneously arising murine plasma-cell malignancy in its native C57BL/KaLwRij host, faithfully recapitulating the marrow infiltration, paraproteinemia and paralytic course of human MM. Alfa Cytology delivers the complete 5T33 workflow—authenticated cell and bone-marrow-passage banking, intravenous inoculation, paraprotein- and paralysis-based monitoring, scheduled dosing and marrow- and survival-inclusive endpoint analysis—giving sponsors decision-ready preclinical datasets shaped to their program, strictly within a preclinical scope.

Overview of 5T33 Syngeneic Model for Multiple Myeloma (MM)

The 5T series begins with a remarkable mouse strain. C57BL/KaLwRij mice develop benign idiopathic paraproteinemia—an MGUS-like state—at high frequency and progress to frank myeloma at roughly one percent per year, mirroring the human epidemiology; whole-genome sequencing later explained part of the predisposition with a Samsn1 deletion and deleterious mutations in Tnfrsf22 and Tnfrsf23 affecting B cells, macrophages and marrow stroma alike. From spontaneous tumors in these mice, Jan Radl’s group at TNO established the transplantable 5T myelomas, and 5T33 became their most aggressive standard-bearer. Cultured in vitro by Manning and colleagues (Cancer, 1990), the cells grow as single elements or small clusters loosely adherent over a stromal layer, double every ~25 hours, and—critically—more than 90% express a monoclonal IgG2b paraprotein. Their tumorigenicity borders on absolute: as few as 500 cells injected into syngeneic recipients induced paralysis and death as early as day 36, with dose-dependent kinetics; after intravenous administration of half a million cultured cells, tumor cells are demonstrable in bone marrow by two weeks and disseminated throughout the animal by three.

Fig 1. Vaccination schedules in the aggressive 5T33MM and moderate 5TGM1 syngeneic models (prime/boost with αCD40), with flow-cytometric analysis of CD107a and PD-1 expression on CD8+ T cells and iNKT cells after immunopeptide mRNA-LNP vaccination. (Van der Vreken, Arne, et al., 2025)

The in vivo disease reads like a clinical chart: malignant plasma cells colonize the marrow—particularly the vertebrae, whose expansion eventually compresses the spinal cord and produces the model’s signature hindlimb paraplegia—while circulating paraprotein rises, the spleen enlarges, and the liver acquires extravascular deposits. In the classic 5T33MMvv propagation, diseased marrow is passaged intravenously into young recipients and myeloma declares itself within three to four weeks; gradient enrichment routinely yields tumor-cell purities near 85%. The 5TMM series, 5T33 included, is the reference arena for myeloma bone-disease research, and the line has carried therapeutic eras with it—proteasome-inhibitor and immunomodulatory screening across the 5T series, invariant natural-killer-T-cell evaluation specifically in 5T33, and the modern antibody and cellular-therapy era. Visualization arrived with eGFP transduction, which let investigators watch paraplegic animals’ tumor deposits directly. Caveats are practical: the C57BL/KaLwRij host is a specialized strain with limited suppliers, fluorescent or luciferase labels must be validated for engraftment in this marrow-homing system, the disease is systemic rather than a measurable solid mass—so paraprotein, paralysis and marrow burden replace calipers—and the three-to-four-week course leaves compressed windows for slower agents.

Cell Line Information: 5T33

Key characteristics of 5T33 and its documented derivatives are summarized below.

Our Services

With in vivo hematology-oncology specialists guiding each stage and ELISA, flow-cytometry and bone-imaging capabilities in-house, Alfa Cytology molds every 5T33 engagement around the sponsor’s question—selecting cultured-cell or marrow-passage inocula, calibrating dose and schedule, and pairing dosing with paraprotein kinetics, paralysis scoring and marrow-burden endpoints for clean, decision-grade preclinical data.

Workflow of 5T33 Syngeneic Model Construction

Construction of the 5T33 syngeneic model is an inoculation workflow whose quality rests on verified cells or marrow, strain-matched recipients and disciplined clinical monitoring. A standard engagement proceeds as follows:

1. Source and qualify material: cultured 5T33 cells (mycoplasma PCR, identity verification, IgG2b-expression check) or 5T33MMvv marrow-passage material (gradient-enriched to ~85% purity); eGFP/luciferase labels are validated for engraftment before use.
2. Prepare recipients: C57BL/KaLwRij mice (typically 6–8 weeks old) complete acclimation and health screening and are individually marked before inoculation.
3. Prepare the inoculum: log-phase cells are washed, counted and resuspended in serum-free medium (5 × 10⁵ cultured cells in a small volume for the standard intravenous format; lower or higher doses tuned to the desired latency).
4. Inoculate: cells are delivered intravenously via the tail vein, homing to bone marrow and declaring disease over the following three to four weeks.
5. Assign groups: animals are randomized by body weight at inoculation, or at first paraprotein detection where designs call for established disease.
6. Dose and follow: test articles are administered on schedule; body weight, hindlimb-paralysis onset and serum paraprotein (ELISA) are recorded weekly, with spleen enlargement and clinical status logged; survival is the primary endpoint.
7. Terminate and analyze: bone marrow, vertebrae, spleen and liver are harvested; tumor burden is quantified by flow cytometry and histology; lytic bone disease is assessed by X-ray or micro-CT; paraprotein levels and survival curves complete the dataset.

Fig 2. 5T33 Syngeneic Model construction workflow.

Case Study-5T33 Syngeneic Model Development

Alfa Cytology keeps an active file of preclinical case studies on the 5T33 platform: establishment-phase optimization of inoculum dose and latency, in vivo disease tracking by paraprotein ELISA, paralysis scoring and imaging, proteasome-inhibitor-, IMiD- and cell-therapy-based intervention studies, and systematic endpoint analyses covering marrow burden, bone disease and survival. Representative paraprotein kinetics, survival curves and endpoint summaries can be shared upon request and will be updated as new programs conclude.

Why Choose Alfa Cytology?

A marrow-homing myeloma with a paraplegic readout rewards hematologic depth, and that is where Alfa Cytology invests:

• Strain-matched C57BL/KaLwRij colonies with documented sourcing and genetic background.
• Dual-format banking: cultured 5T33 cells and 5T33MMvv marrow-passage material with gradient enrichment.
• Paraprotein-ELISA monitoring as a live, quantitative efficacy readout.
• Paralysis-scoring expertise reflecting the model’s clinical signature endpoint.
• Bone-disease evaluation with X-ray/micro-CT in the series’ reference bone microenvironment.
• Compressed-course scheduling tuned to the three-to-four-week disease tempo.
• One accountable project contact with milestone-by-milestone visibility.
• A strictly preclinical scope—every study is planned, executed and reported as non-clinical research.

Contact Us

Interested in the 5T33 syngeneic multiple myeloma model for your next preclinical program? Reach out to us with your agent, timeline and endpoint wish-list, and the Alfa Cytology team will respond with a customized plan covering model setup, dosing strategy and analysis workflow—contact us today and move your program forward with confidence.

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