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Updated: Aug 8, 2026
Adenoviral Transduction of Naive CD4 T Cells to Study Treg Differentiation
Published on: August 13, 2013
Targeted adenovirus-mediated gene delivery to T cells via CD3
T J Wickham1, G M Lee, J A Titus
1GenVec, Inc., Rockville, Maryland 20852-1709, USA. wickham@genvec.com
Abstract:
T cells are primary targets in numerous gene therapy protocols. However, the use of subgroup C adenovirus serotype 2 or 5 (Ad2 or Ad5) as a vector to transduce T cells is limited by its poor transduction efficiency for these cells. In this report we show that poor T-cell transduction results from these cells lacking both the primary Ad2-Ad5 receptor, used in attachment, and the secondary Ad receptor, which mediates entry of most adenovirus serotypes. These deficiencies were overcome by using a bispecific antibody (bsAb) with specificities for human CD3 and for a FLAG epitope genetically introduced into Ad5 (Ad.FLAG) to redirect the virus to human T cells. The anti-FLAG x anti-CD3 bsAb increased Ad.FLAG binding 30-fold, induced the efficient uptake of Ad.FLAG into the cells, and led to a 100- to 500-fold increase in the transduction of resting T cells. Moreover, fluorescence-activated cell sorter analysis showed that 25 to 90% of the T cells were transduced by the bsAb-complexed Ad.FLAG at multiplicities of infection between 20 and 100 active particles per cell. These results demonstrate that bsAbs can target Ad to non-Ad receptors on cells that are normally resistant to Ad, resulting in their efficient and specific transduction.
Insights
Gene therapy targeting T cells faces challenges with adenovirus vector efficiency. A novel bispecific antibody (bsAb) overcomes this by redirecting adenovirus to T cells, significantly enhancing gene delivery.
Area of Science:
- Immunology
- Gene Therapy
- Virology
Background:
- T cells are crucial targets for gene therapy.
- Adenovirus serotype 2 or 5 (Ad2/Ad5) vectors exhibit poor T-cell transduction efficiency.
- This inefficiency stems from T cells lacking essential adenovirus receptors for attachment and entry.
Purpose of the Study:
- To investigate a method for improving adenovirus-mediated gene delivery to T cells.
- To overcome the limitations of Ad2/Ad5 vector transduction in T cells.
Main Methods:
- Utilized a bispecific antibody (bsAb) targeting human CD3 and a FLAG epitope on modified Ad5 (Ad.FLAG).
- Redirected Ad.FLAG vectors to T cells via the bsAb.
- Assessed viral binding, cellular uptake, and transduction efficiency using fluorescence-activated cell sorter (FACS) analysis.
Main Results:
- The anti-FLAG x anti-CD3 bsAb enhanced Ad.FLAG binding by 30-fold.
- Efficient uptake of Ad.FLAG into T cells was observed.
- Achieved a 100- to 500-fold increase in transduction efficiency of resting T cells.
- FACS analysis indicated 25-90% T-cell transduction with bsAb-complexed Ad.FLAG.
Conclusions:
- Bispecific antibodies can effectively target adenoviruses to cells lacking natural receptors.
- This strategy overcomes resistance to adenovirus transduction in T cells.
- Demonstrated efficient and specific gene delivery to T cells using bsAb-redirected adenoviral vectors.
