Document Type

Journal Article

Publication Date

6-2015

Journal

PLoS One

Volume

10

Issue

6

Inclusive Pages

e0129237

DOI

10.1371/journal.pone.0129237

Keywords

Cancer Vaccines--immunology; Inhibitor of Differentiation Protein 2--immunology; Lymphocyte Depletion--methods; Neuroblastoma--immunology; RNA Interference--immunology

Abstract

Tumor vaccines have held much promise, but to date have demonstrated little clinical success. This lack of success is conceivably due to poor tumor antigen presentation combined with immuno-suppressive mechanisms exploited by the tumor itself. Knock down of Inhibitor of differentiation protein 2 (Id2-kd) in mouse neuroblastoma whole tumor cells rendered these cells immunogenic. Id2-kd neuroblastoma (Neuro2a) cells (Id2-kd N2a) failed to grow in most immune competent mice and these mice subsequently developed immunity against further wild-type Neuro2a tumor cell challenge. Id2-kd N2a cells grew aggressively in immune-compromised hosts, thereby establishing the immunogenicity of these cells. Therapeutic vaccination with Id2-kd N2a cells alone suppressed tumor growth even in established neuroblastoma tumors and when used in combination with immune checkpoint blockade eradicated large established tumors. Mechanistically, immune cell depletion studies demonstrated that while CD8+ T cells are critical for antitumor immunity, CD4+ T cells are also required to induce a sustained long-lasting helper effect. An increase in number of CD8+ T-cells and enhanced production of interferon gamma (IFNγ) was observed in tumor antigen stimulated splenocytes of vaccinated mice. More importantly, a massive influx of cytotoxic CD8+ T-cells infiltrated the shrinking tumor following combined immunotherapy. These findings show that down regulation of Id2 induced tumor cell immunity and in combination with checkpoint blockade produced a novel, potent, T-cell mediated tumor vaccine strategy

Comments

Reproduced with permission of PLoS ONE.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

Peer Reviewed

1

Open Access

1

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