# LentiTag: A novel approach to the efficient manufacturing of active lentiviral vectors

> **NIH NIH R43** · ISOLERE BIO, INC. · 2022 · $255,556

## Abstract

PROJECT SUMMARY
Cell and gene therapies are garnering attention for their remarkable clinical outcomes and their promise to treat
diseases previously considered uncurable. Lentiviral vectors (LVs) are used in over one third of applications in
cell and gene therapies.2 As with most viral vector and vaccine manufacturing, LVs are challenging and
expensive to manufacture and there are no methods in commercial use that offer specificity, high yield, and
scalability. Current manufacturing relies on anion exchange chromatography, which (1) has poor capacities for
large viruses that cannot effectively diffuse into small resin pores, (2) necessitates additional purification steps
because its lack of LV specificity causes contaminant co-purification, and (3) requires harsh elution conditions
that result in low infectious LV recoveries of only ~50%.15, 1 In this Phase I SBIR proposal, Isolere Bio will develop
a fusion protein reagent comprised of an affinity domain that is specific for LV and a proprietary biopolymer
domain that has robust and precisely tunable liquid-liquid phase separation behavior. The LentiTag™ reagent
will capture LVs in solution with high specificity and then efficiently sequester them into phase separated droplets
on command with a simple environmental trigger — an incremental adjustment in salt. These droplets, highly
pure and concentrated, are easily separated from all excluded contaminants with tangential flow filtration (TFF),
a unit operation that scales up simply and enables high volumetric throughput. Once host cell proteins and other
cellular contaminants have been washed away, the LV can be gently recovered from the droplets with an elution
buffer that disrupts the affinity interaction at near-neutral pH. To demonstrate LentiTag™’s technical feasibility,
Isolere will first design, produce, and characterize an LV-specific capture protein (LCP). The LCP binds the most
common LV envelope glycoprotein and phase separates at ambient temperature with a small increase in salt
(<0.35M NaCl) that is tolerated by labile LVs. Having defined optimal capture conditions, we will next perform
high-throughput screening of LV-compatible elution buffers and then optimize key filtration process parameters,
including pore size and permeate flow rate. We will perform a side-by-side comparison of LentiTag™ to the
standard industry process, quantifying final LV concentration, infective titer, yield, purity, and total processing
time. Last, because the LCP is well-hydrated and sterically occluding in its soluble state, we also hypothesize
that it can confer protective and stabilizing effects to LVs, which are prone to progressive activity loss and
aggregation during storage. Our final aim is to explore the impact of our reagent on LV stability, both during
upstream production (preventing host cell auto-transduction) and as an additive to formulated LV stored at
temperatures ranging from -70ºC to 37 ºC. The LentiTag™ technology will provide a scala...

## Key facts

- **NIH application ID:** 10384822
- **Project number:** 1R43GM144018-01A1
- **Recipient organization:** ISOLERE BIO, INC.
- **Principal Investigator:** Kelli Michelle Luginbuhl
- **Activity code:** R43 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $255,556
- **Award type:** 1
- **Project period:** 2022-02-01 → 2022-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10384822

## Citation

> US National Institutes of Health, RePORTER application 10384822, LentiTag: A novel approach to the efficient manufacturing of active lentiviral vectors (1R43GM144018-01A1). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10384822. Licensed CC0.

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