In Vivo CAR-T Therapy: The Next Generation Cell Therapy Technology Revolution
CAR-T cell therapy involves genetically modifying a patient's T cells to express chimeric antigen receptors (CARs) that specifically recognize tumor-associated antigens, thereby enabling precise tumor killing. Traditional ex vivo CAR-T therapy has been well-validated in hematologic malignancies. However, its complex manufacturing process — leukapheresis, in vitro activation, viral transduction, expansion culture, cryopreservation, transportation and preinfusion lymphodepletion — results in a "vein-to-vein" cycle of 2–7 weeks. The products are highly personalized with significant batch-to-batch variability and the cost per patient can reach hundreds of thousands to millions of dollars, severely limiting patient access.
In vivo CAR-T therapy emerged as a disruptive technological approach against this backdrop. Unlike ex vivo preparation, in vivo CAR-T uses a single “off-the-shelf” formulation for direct administration, achieving CAR gene delivery and expression within the patient's body to generate functional CAR-T cells. This technological approach achieved breakthrough progress between 2025 and 2026:
• Kelonia Therapeutics' KLN-1010 achieved MRD-negative remission in a Phase I trial for multiple myeloma without the need for lymphodepleting chemotherapy.
• Phase I data for Japan's ESO-T01 anti-BCMA CAR-T therapy similarly demonstrated in vivo CAR-T cell generation without leukapheresis or lymphodepleting chemotherapy.
• Academic studies have confirmed that in vivo CAR-T cells can expand to up to 40% of total immune cells in vivo, successfully clearing tumor cells from the bone marrow and spleen.
The core advantages of in vivo CAR-T can be summarized as:
Significantly simplified workflow
Drastically shortened treatment timeline
Cost reduction of over 90%
Broader applicability to patient populations
Ability to achieve T cell epitope spreading within an intact immune network
In vivo CAR-T Workflow and TransGen Product Support
The development and production of in vivo CAR-T therapy can be divided into three main stages: Upstream R&D — Delivery Vector Preparation — Quality Control and Validation. Current technological approaches mainly include:
Technology Route | Core Carrier | Advantages |
Targeted Viral Vector Delivery | Engineered lentivirus/retrovirus (with targeting ligands) | Persistent gene integration, strong CAR activity |
LNP Delivery | Lipid nanoparticle-delivered mRNA | High safety, simple process, no integration risk |
Exosome Delivery | Engineered exosomes loaded with CAR mRNA | Low immunogenicity, convenient storage and transport |
With a comprehensive product portfolio covering molecular biology, cell biology and protein research, TransGen Biotech provides total solutions for the entire in vivo CAR-T workflow.
I. Upstream R&D — CAR Gene Design and Plasmid Construction
The upstream starting point of in vivo CAR-T is the structural design of the CAR gene and the construction of plasmid vectors. Regardless of whether the subsequent route is viral vectors, LNPs or exosomes, this stage is a core step shared by all technology routes. The structural design of the CAR gene determines the functional characteristics of CAR-T cells, while plasmid vector construction is a key step in introducing the CAR gene into the delivery system. TransGen Biotech has a rich product portfolio in gene cloning and plasmid construction.
Core Product Recommendations
Category | Product | Features |
High-Fidelity Amplification | • Fast amplification: ≤5 kb genes at 12 kb/min; >5 kb genes at 6 kb/min • Fidelity 108× that of EasyTaq® • Genomic DNA fragment amplification（≤15 kb） • Plasmid DNA fragment amplification（≤20 kb） | |
Seamless Cloning | • Supports one-step ligation of up to 15 fragments • Fast recombination in 5–15 minutes • Can construct plasmids up to 31.8 kb • Compatible with fragments as low as 0.003 pmol • Provides online primer design tool | |
Endotoxin-Free MaxiPrep | EasyPure® 1-Tube Universal EndoFree Pro Plasmid MaxiPrep Kit ( for 100-500 ml ) (EM153) | • One-Tube: Complete lysis and neutralization of 100–500 ml bacterial culture in a single 50 ml tube; no large-volume consumables needed • Visual: Solution LB III (blue) indicates complete lysis/neutralization by color change • Fast: Small volume with large spin column reduces centrifugation steps and saves time • Endotoxin-free: Purified plasmid contains<0.1 EU/μg endotoxin, as low as 0.001 EU/μg • High yield: Column nucleic acid capacity up to 5 mg |
After upstream plasmid construction, there are multiple technological options for in vivo CAR-T. TransGen's product line simultaneously covers viral, LNP and exosome routes, providing customers with comprehensive technology options.
Plasmid Design Differences Among the Three Main Technology Routes
• Lentiviral Vector Route: Uses multi-plasmid co-transfection of packaging cells to produce recombinant lentiviral particles capable of targeting T cells. Specifically employs a three- or four-plasmid system, including a CAR expression plasmid, packaging plasmids (Gag/Pol/Rev) and an envelope plasmid (containing T cell-targeting ligands such as anti-CD3 scFv).
• LNP Delivery Route (Non-Viral): Uses in vitro transcribed (IVT) mRNA as the core functional molecule, encapsulated in lipid nanoparticles for in vivo delivery. The IVT plasmid contains, in addition to the CAR sequence, a T7 promoter, optimized 5'UTR/3'UTR and a Poly(A) tail; the self-amplifying RNA (saRNA) route requires additional insertion of viral replicase sequences.
• Exosome Delivery Route (Non-Viral): Uses engineered exosomes that naturally load CAR-mRNA and display targeting molecules, offering high safety and convenient storage/transport. This route involves a targeting plasmid (displaying T cell ligands via scaffold fusion proteins), a CAR plasmid (containing exosome sorting signals) and a scaffold protein expression plasmid. Functional exosomes are obtained after co-transfection of producer cells.
mRNA In Vitro Synthesis (Raw Material Preparation for LNP and Exosome Routes)
The core functional molecule for non-viral routes is mRNA. Both LNP and exosome delivery typically rely on in vitro transcription (IVT) technology to synthesize CAR-mRNA. Its purity, capping efficiency and tailing uniformity directly affect in vivo translation efficiency and CAR expression levels. TransGen provides a complete mRNA synthesis product line covering transcription, capping and tailing.
Core Product Recommendations
Category | Product | Features |
T7 In Vitro Transcription | T7 High Efficiency Transcription Kit (N1-me-Pseudo UTP) (JT102) | • Generates 120–180 μg RNA per 20 μl reaction • UTP replaced with N1-Methyl-Pseudo-UTP for lower immunogenicity, better RNA stability, higher expression efficiency |
• One-step transcription and capping for easy operation • Higher capping efficiency with cap analog • Generates 120–160 μg RNA per 20 μl reaction • UTP replaced with N1-Methyl-Pseudo-UTP for lower immunogenicity, better RNA stability, higher expression efficiency | ||
mRNA Modification | • Simple and fast, obtain Cap1 products within 1 hour, high capping efficiency • Can cap mRNA of different lengths; scalable reactions • Complete capping reaction reagents provided; only RNA required | |
• High tailing efficiency and consistent poly(A) length • Scalable reactions • Capped mRNA can be directly used for tailing with TransGen product (LA201) • Complete tailing reaction reagents provided; only RNA required |
II. Delivery Vector Preparation and Production
This stage is the critical transition where in vivo CAR-T moves from a genetic blueprint to a functional product. It transforms nucleic acid molecules into in vivo delivery formulations, determining the vector's targeting ability, transduction/transfection efficiency and process scalability. Different technology routes require distinct production strategies: the lentiviral route focuses on packaging cell transfection and virus particle purification/concentration, while the LNP and exosome routes focus on nanoparticle assembly and loading efficiency. High-quality vector preparation directly determines the in vivo generation efficiency and therapeutic safety of CAR-T cells.
Lentiviral Vector Route:
Lentivirus is the most mature vector for in vivo CAR-T, enabling T cell-specific transduction and long-term CAR gene integration. Stable virus packaging and efficient concentration are the foundations for ensuring in vivo efficacy and dose consistency.
Core Product Recommendations
Category | Product | Features |
Transfection Reagent | • Broad application: Suitable for transient and stable transfection of various adherent and suspension cells (HEK-293, CHO, etc.) • High efficiency: >90% transfection efficiency for HEK-293 and HEK-293-F; >80% for CHO-S and CHO-K1 • Low toxicity: Good morphology of transfected adherent cells; >90% viability for suspension cells • Easy to use: No medium change before/after transfection; compatible with antibiotics and serum; no freezing required | |
Lentiviral Concentration | • No ultracentrifugation needed; simple and fast • Up to 90% recovery of lentiviral particles; titer can be increased up to ~100-fold |
Exosome Delivery Route: Engineered Exosome Production
Engineered exosomes, as natural nanoscale delivery vehicles, combine low immunogenicity with the advantage of engineerability. By co-transfecting producer cells with multiple plasmids, exosomes that both load CAR-mRNA and display T cell-targeting ligands can be obtained.
Core Product Recommendations
Category | Product | Features |
Mesenchymal Stem Cell Culture | TransStem® Serum-Free, Xeno-Free Human Mesenchymal Stromal Cell Medium (GMP Grade)(MM101 (with phenol red)/MM102 (without phenol red)) | • Efficient expansion: Small cell diameter (15–17 μm); high yield (1012-1014 umbilical cord MSCs from P0–P5) • High safety: Serum-free, xeno-free • Good efficacy: High differentiation potential (osteogenic, chondrogenic, adipogenic) and strong immunomodulatory capacity • Broad applicability: Suitable for MSCs from umbilical cord, bone marrow, adipose tissue, and pluripotent stem cell-derived MSCs • Pharmaceutical-grade raw materials: Produced under FDA cGMP standards, FDA DMF Type II filed |
Exosome Extraction | • Simple operation, no ultracentrifugation; purify exosomes within 3 hours • Higher specificity and purity than ultracentrifugation • Gentle elution conditions; extracted exosomes have good morphology, intact structure, and high activity | |
• Simple operation, no ultracentrifugation • Low sample volume requirement, high sensitivity |
III. Quality Control and Validation
Unlike ex vivo CAR-T therapy, in vivo CAR-T lacks an in vitro culture step to serve as a quality control checkpoint, thereby imposing higher demands on the quality control and standardized production of delivery vectors. TransGen provides a complete quality control toolkit covering titer, host residue and mycoplasma detection.
1. Titer Determination
Physical titer (p24 protein) and infectious titer (transducing units) are critical quality attributes of lentiviral vectors, directly affecting the generation efficiency and dose accuracy of in vivo CAR-T cells.
Core Product Recommendations
Category | Product | Features |
qPCR Method | • Simple, fast, high sensitivity • Compatible with second- and third-generation HIV-1 lentiviral packaging vectors | |
ELISA Method | • Wide detection range: 3.13–200 pg/ml • High accuracy: 85–115% recovery • High sensitivity: 1.0 pg/ml • Good precision: Intra-assay CV<10%, inter-assay CV <15% | |
• Wide detection range: 31.3–2000 pg/ml • High accuracy: 80–120% recovery • High sensitivity: 10.0 pg/ml • Good precision: Intra-assay CV<10%, inter-assay CV<15% • Easy operation: One-step sample addition; total incubation time only 70 minutes |
2. Host Nucleic Acid Residue Detection
Residual DNA from producer cells (e.g., HEK293T) is an important safety indicator for viral vectors. TransGen's residue nucleic acid detection series uses qPCR with high specificity, high sensitivity and a dUTP/UDG contamination control system to prevent false positives from PCR product contamination.
Core Product Recommendations
Product | Limit of Quantification | Features |
1×10-2 pg/μl | • High specificity, sensitivity and amplification efficiency; wide sample compatibility • Specially optimized qPCR buffer for higher extension speed, sensitivity, and specificity • Uses UDG enzyme and dUTP to prevent crosscontamination; accurate data | |
1.5×102 copies/μl |
3. Mycoplasma Detection
Mycoplasma contamination is a red-line indicator for cell therapy products. TransGen provides three technology platforms: qPCR, direct qPCR and luminescence, adapted to different sample types and throughput requirements.
Core Product Recommendations
Category | Product | Features |
qPCR Method | • Complies with European Pharmacopoeia EP 2.6.7 and Japanese Pharmacopoeia JP G3 • Broad coverage: Validated for 13 strains and plasmid DNA; database comparison covers at least 129 mycoplasma DNA sequences • High sensitivity: 95% detection rate for validated mycoplasma; LOD 10 CFU/ml; plasmid standard 1 copy/μl • High specificity: No interference from ~20 common bacteria or producer cell genomes • dUTP/UDG contamination control system • High stability: withstand at least 15 freeze-thaw cycles with no performance loss • Compatible with MagicPure® Mycoplasma DNA Kit (EH401) | |
Direct qPCR Method | • Direct sample amplification: No sample pretreatment needed • Fast detection: No extraction; results in 70 minutes • High sensitivity: Detects as low as 10 copies of mycoplasma plasmid standard • Strong inhibition resistance: Amplifies in the presence of common matrices like cell culture medium and FBS • Good specificity: Cross-validated with various bacteria and engineered cells, with no non-specific amplification • Broad coverage: Detects up to 129 mycoplasma species • Good stability: No significant change after 15 freeze-thaw cycles | |
Luminescence Method | • Simple and time-saving: Two steps, results in 20 minutes • High sensitivity: Detects as low as 50 CFU/ml, avoiding false negatives • Good replicate reproducibility; accurate result interpretation |
IV. Cell Platform and In Vivo Model Validation Stage
Although in vivo CAR-T avoids the in vitro cell culture step, cell models are still needed during the R&D phase to validate the specific transduction/transfection efficiency of various delivery vectors into T cells, CAR expression levels and T cell activation, proliferation and killing functions. TransGen provides a complete set of reagents for cell culture, cryopreservation and functional assays.
Core Product Recommendations
Category | Product | Features |
T Cell Serum-Free Medium | ArtMedia® Human T Cell Serum-Free Medium (GMP Grade)(MT101 (with phenol red)/MT102 (without phenol red))
| • Independently developed • Serum-free, xeno-free, chemically defined • Supports rapid expansion and high-density culture of T cells • Compatible with multiple T cell activation methods (soluble antibody, coated antibody, magnetic bead-conjugated antibody) • Produced and managed under GMP standards |
Cell Cryopreservation Solution | • Safe: Serum-free, animal-free, protein-free, DMSO-free, chemically defined, pharmaceutical-grade, toxicity-tested • Efficient: Improves cell recovery viability; >90% recovery for most cells (including MSCs and immune cells) • Convenient: Ready-to-use; no programmed freezing required | |
Cell Assays | • Fast, sensitive • Low cytotoxicity • Wide linear range • Stable, reproducible results | |
TransDetect® Bright-Luc Pro Firefly Luciferase Reporter Assay Kit (FR106) | • No irritating odor; safer to use • One-step lysis and detection; no washing or cell collection • Strong chemiluminescent signal, high sensitivity • Complete 96-well plate detection within 10 minutes • Half-life of 30–40 minutes; suitable for 5-plate throughput • Pre-validation according to ICH guidelines | |
TransDetect® Luminescent Cell Viability Detection Kit (FC401) | • High luminescence: Significantly enhanced signal; bright, distinguishable signal even at low cell numbers • Half-life up to 3 hours; signal remains >85% within 1 hour • Wide linear range: Good linear relationship from 10–100,000 cells • Visual color indicator: The reagent comes with its own color, effectively preventing missed or incorrect additions • Visual color indicator: The reagent comes with its own color, effectively preventing missed or incorrect additions • Simple operation: Single-component reagent; detect within 10 minutes after addition to cell culture; suitable for high-throughput screening | |
ELISA | • High sensitivity (pg level), wide linear range • Pre-coated antibodies for simple operation • Targets: Human IL-1β, IL-2, IL-6, IL-10, IL-12 p70, TNF-α, IFN-γ, GM-CSF, FGF basic |
TransGen's End-to-End In Vivo CAR-T Solution
In vivo CAR-T replaces the traditional individualized manufacturing process with an "off-the-shelf" formulation, promising to fundamentally address accessibility and cost bottlenecks and become the next technological high ground in cell therapy. The field currently features three parallel routes: viral vectors, LNP delivery and exosome delivery. TransGen Biotech, with over a decade of independent R&D in biological reagents, has a product portfolio covering key steps such as gene cloning, virus packaging, transfection reagents, cell culture and quality control, with mature applications in CAR-T immunotherapy and stem cell therapy.
R&D Stage: Provides products to support CAR gene design, envelope protein modification and targeting molecule screening/validation.
Vector Production Stage: Provides GMP-grade PEI transfection reagent for stable, efficient and batch-to-batch consistent high-titer virus production; exosome extraction/purification product lines are continuously expanding.
Quality Control: Provides p24 ELISA (physical titer), lentivirus qPCR titer detection, mycoplasma detection and other QC tools, compliant with GMP quality management system requirements.
Cell Platform: Covers core cell culture needs including GMP-grade cell culture media, cell cryopreservation, and functional assay reagents.
TransGen Biotech will continue to empower cell therapy innovation companies with solid technology and product output, facilitating the rapid development of this novel cell therapy.
