Author of

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  O08 - Preclinical Therapeutic Models I (ID 92)

  • Event: WCLC 2013
  • Type: Oral Abstract Session
  • Track: Biology
  • Presentations: 1
  • Moderators:C. Mascaux, R. Natale
  • Coordinates: 10/28/2013, 16:15 - 17:45, Bayside Auditorium A, Level 1

  • 11375

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    O08.03 - T-cell Imaging to Noninvasively Monitor Adoptive T-cell Therapy for Thoracic Malignancies (ID 2994)

    16:35 - 16:45  |  Author(s): V. Ponomarev
    • Abstract
    • Presentation
    • Slides

    Background
    Noninvasive T-cell imaging technology allows monitoring of adoptive T-cell responses without the need for invasive biopsies. Herein, we report dynamic imaging of tumor-targeted T cells in preclinical models by use of luminescent-enhanced firefly luciferase vector, and we further demonstrate the successful use of a clinical-grade herpes simplex virus type 1 thymidine kinase (HSV1-tk)–incorporated vector for monitoring of T-cell trafficking, antigen-specific proliferation, and biodistribution.

    Methods
    T cells transduced with mesothelin-targeted chimeric antigen receptors (M28z) were either cotransduced with an enhanced firefly luciferase vector (effLuc-M28z) or singly transduced with HSV1-tk-M28z (TK-M28z). To simultaneously visualize tumor during T-cell PET imaging, cancer-cell imaging was performed using MSTO-GFP/ffLuc+ (MSTO-211H cells transduced to express mesothelin and the green fluorescent protein/firefly luciferase fusion protein). In vitro, uptake of [18]F-FEAU radiotracer by T cells was measured by [3]H channel counting. In vivo studies used either SCID-beige or NSG mice bearing pleural or flank tumors. Bioluminescence imaging (BLI) quantification was determined by the mean number of photons per second in the region of interest. PET imaging with [18]F-FEAU was performed in a 3-dimensional microPET scanner. T-cell imaging results were validated by flow cytometric and immunohistochemical analysis of harvested tissue.

    Results
    Quantification studies showed a linear relationship between photon emission and T-cell number both in vitro and in vivo. In vivo, evaluation of T-cell biodistribution kinetics, by intravenous administration of effLuc-M28z T cells into mice bearing flank tumors, demonstrated initial accumulation of T cells in the lungs, liver, and spleen and progressive accumulation in the tumor (Figure 1A). Pleurally administered effLuc-M28z+ T cells displayed an increasing BLI signal (5-fold; p<0.01) in response to antigen 72 hours after administration, compared with pleurally administered effLuc+ T cells alone (control) (Figure 1B). T-cell accumulation in pleural tumor and extrathoracic sites (spleen) was confirmed by flow cytometric analysis of tissues harvested at serial time points (Figure 1C). These results were reproduced with clinical-grade vector TK-M28z+ T cells administered intrapleurally in mice bearing pleural tumor. Serial [18]F-FEAU PET imaging showed antigen-specific T-cell accumulation with decreasing tumor burden, as seen by corresponding tumor BLI (Figure 1D). Figure 1

    Conclusion
    We provide an optimized method for monitoring of T-cell trafficking, localization and proliferation in thoracic malignancies. Our findings—derived using a clinical-grade imaging construct and substrate—provide convincing evidence for the use of noninvasive T-cell monitoring in our upcoming adoptive T-cell therapy clinical trial.

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