G-Link CD3

A precision-engineered adapter protein that retargets lentiviral vectors (LV) to CD3, activating T cells and enhancing transduction in a single step. 

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A Precision Adapter for Efficient CD3 Targeting

The G-Link CD3 adapter protein binds to wild-type VSV-G on the surface of LV particles and retargets them to CD3. In addition to G-binding and CD3-retargeting domains, the G-Link CD3 adapter protein includes a trimerizing linker, enabling high-avidity attachment to G. The adapter protein is designed to release in the endosome, allowing normal cell membrane fusion and cell transduction.

G-Link process infographic

Benefits of the Cellective Lentiviral Vector Delivery Platform

G-Link CD3 enables selective transduction of CD3-positive T cells. The G-Link CD3-targeting domain binds specifically to CD3 to mediate T-cell binding, while the G-binding domain not only anchors G-Link CD3 to G but also prevents G from binding to its natural receptors and the trimerizing linker enhances overall adapter stability. Together, these components mask entry through native receptors while retargeting delivery to CD3.

GFP-encoding LV pseudotyped with VSV-G was used directly or following retargeting with G-Link CD3 to transduce Jurkat (CD3+) and Jurkat-TCR-KO (CD3-) cells. GFP signal in the cells was imaged (left) and quantitated (right) 3 days post-transduction.

G-Link CD3 boosts transduction of resting T cells, simplifying workflows. LVs retargeted using G-Link CD3 effectively transduce and active T-cells in one step, so PBMCs can be transduced without the need for pre-activation using beads or cytokine cocktails. 

Resting human PBMCs were transduced at 1000 LVP/cell with GFP-encoding (top) or BCMA-CAR-encoding (bottom) LVs pseudotyped with VSV-G. LVs were used directly (left) or retargeted using G-link (right).

PBMCs were incubated with VSV-G-pseudotyped LV (left), VSV-G-pseudotyped lentivirus retargeted with G-Link CD3 (middle), or G-Link CD3 only (right). The T-cell activation marker CD25 was measured 7 days after transduction.

G-Link CD3-retargeted LVs work in vivo to target and transduce T cells. 

NSG DKO mice bearing BCMA+ OPM2-luciferase tumors were humanized with PBMCs. One week later (Day 0), mice were injected via tail vein with saline control, G-Link CD3 only, or BCMA-CAR encoding LV retargeted with G-Link CD3. Tumor burden was monitored over time by bioluminescence imaging. v

The G-Link CD3 Workflow

For both in vitro and in vivo applications, reach your intended target with Cellective. Here’s how:

Step 1: Complexation

G-Link CD3 is mixed with the LV to create a capped, retargeted vector.

Step 2: Transduction

The capped LV is added to cell cultures or administered to mice.

Step 3: Analysis

Transgene expression and T-cell activation assessed.