In vivo CAR-T: where lentivirus, AAV, and LNP each fit

In vivo CAR-T means engineering a patient's own T cells in their bloodstream — no apheresis, no manufacturing facility, no two-week wait. It's one of the biggest open questions in cell therapy right now, and there are three routes that researchers are running in parallel.

The lentiviral route uses a re-engineered HIV-derived vector to permanently integrate a CAR transgene into T cells in vivo. The upside is durability — once integrated, the CAR stays. The downside is integration site uncertainty, immunogenicity of the viral capsid, and the manufacturing complexity that comes with a live virus. EsoBiotec's ESO-T01 program is the visible example of this approach, and the disclosure that they have a route to in vivo CAR-T using lentiviral particles was a notable signal at the Antibody 2026 conference.

The AAV route uses an adeno-associated virus to deliver an episomal CAR. It has lower long-term durability than lentivirus (because AAV doesn't integrate efficiently) and is bottlenecked by serotype-driven tropism — you need an AAV serotype that finds T cells, and most do not. The upside is a cleaner safety profile and easier manufacturing than lentivirus.

The LNP route — which is what SunVax sits inside — uses lipid nanoparticles to deliver mRNA encoding the CAR. The CAR expression is transient (mRNA is translated, then degraded), so durability is limited. But the safety profile is much cleaner: no viral integration, no permanent change, no need for serotype-matching. Repeat dosing is conceptually possible, though the data is still preliminary (SunVax openly says repeat-dosing immune profile is one of their open gaps).

For a researcher today, the practical sort is: if you need to demonstrate durable in vivo CAR-T in a mouse model and want viral durability, go lentiviral. If you need an ex vivo CAR-T enhancement study, the SV106 kit (human CD8 T targeting) is the cleanest LNP-based option in the SunVax catalog. If you're exploring antigen-priming with transient CAR expression, the LNP route is the right starting point, with the understanding that durability is short.

This site exists to help with the third bucket. We aren't going to oversell. The lentiviral and AAV routes have well-funded teams (EsoBiotec, Capstan, Umoja, and others), and we don't write copy that pretends LNPs are a replacement for them — they're a complementary tool with different durability and safety trade-offs.