Volume 3 Supplement 1

Current and Future Applications of Focused Ultrasound 2014. 4th International Symposium: abstracts

Open Access

T-cell mediated immune response to HIFU-induced liquefaction of murine B16 melanoma

  • Tatiana Khokhlova1
Journal of Therapeutic Ultrasound20153(Suppl 1):O43

DOI: 10.1186/2050-5736-3-S1-O43

Published: 30 June 2015

Background/introduction

Anti-tumor immune response caused by High Intensity Focused Ultrasound (HIFU) therapy has been a subject of controversy. Most agree that the response is more likely to be induced by mechanical, rather than thermal effects of HIFU. The goal of the current work was to study the effect of HIFU-induced liquefaction of a tumor on tumor-specific and non-specific T-cell mediated immune response in a mouse model.

Methods

B16 melanoma was inoculated in a hind limb of B6 wild type mice. When the tumor reached the diameter of 1 cm, it was treated with HIFU optimized for boiling histotripsy (BH) - a technique utilizing millisecond-long pulses to create boiling bubbles via rapid shockwave heating. The interaction of shocks with the ensuing vapor cavity fractionates tissue into subcellular debris with negligible thermal effect. The control group received sham treatment. Groups of animals were sacrificed 2 and 7 days post treatment, and the lymphatic organs, blood and tumor tissue were analyzed by flow cytometry for T cell and dendritic cell activation status, phenotype, specificity and reactivity.

Results and conclusions

Although BH delayed the tumor growth compared to the control group, it did not change subsequent growth rate. No statistically significant difference from the control group was found in neither the number, nor the phenotype and activation of cytotoxic, helper and regulatory T cells (neither tumor-specific, nor non-specific). Activation status of the dendritic cells was also unaltered by the treatment. However, a two-fold difference in the number of non-dendritic cells bearing MHCII receptor was found in the spleen and inguinal lymph nodes suggesting a humoral response. These results indicate that T cell mediated mechanism is unlikely to be triggered by BH alone, but warrant further investigation of the systemic effects of this unique treatment modality.

Declarations

Acknowledgements (Funding)

Work supported by NIH DK007742 and NSBRI through NASA NCC 9-58.

Authors’ Affiliations

(1)
University of Washington

Copyright

© Khokhlova; licensee BioMed Central Ltd. 2015

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

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