In vivo imaging of lymph node migration of MNP- and (111)In-labeled dendritic cells in a transgenic mouse model of breast cancer (MMTV-Ras).

PURPOSE

The authors present a protocol for the in vivo evaluation, using different imaging techniques, of lymph node (LN) homing of tumor-specific dendritic cells (DCs) in a murine breast cancer model.

PROCEDURES

Bone marrow DCs were labeled with paramagnetic nanoparticles (MNPs) or (111)In-oxine. Antigen loading was performed using tumor lysate. Mature DCs were injected into the footpads of transgenic tumor-bearing mice (MMTV-Ras) and DC migration was tracked by magnetic resonance imaging (MRI) and single-photon emission computed tomography (SPECT). Ex vivo analyses were performed to validate the imaging data.

RESULTS

DC labeling, both with MNPs and with (111)In-oxine, did not affect DC phenotype or functionality. MRI and SPECT allowed the detection of iron and (111)In in both axillary and popliteal LNs. Immunohistochemistry and γ-counting revealed the presence of DCs in LNs.

CONCLUSIONS

MRI and SPECT imaging, by allowing in vivo dynamic monitoring of DC migration, could further the development and optimization of efficient anti-cancer vaccines.