Brandon Kwong

Localized immunotherapy via liposome-anchored Anti-CD137 + IL-2 prevents lethal toxicity and elicits local and systemic antitumor immunity.

Immunostimulatory agonists such as anti-CD137 and interleukin (IL)-2 have elicited potent antitumor immune responses in preclinical studies, but their clinical use is limited by inflammatory toxicities that result upon systemic administration. We hypothesized that by rigorously restricting the biodistribution of immunotherapeutic agents to a locally accessible lesion and draining lymph node(s), effective local and systemic antitumor immunity could be achieved in the absence of systemic toxicity. We anchored anti-CD137 and an engineered IL-2Fc fusion protein to the surfaces of PEGylated liposomes, whose physical size permitted dissemination in the tumor parenchyma and tumor-draining lymph nodes but blocked entry into the systemic circulation following intratumoral injection. In the B16F10 melanoma model, intratumoral liposome-coupled anti-CD137 + IL-2Fc therapy cured a majority of established primary tumors while avoiding the lethal inflammatory toxicities caused by equivalent intratumoral doses of soluble immunotherapy. Immunoliposome therapy induced protective antitumor memory and elicited systemic antitumor immunity that significantly inhibited the growth of simultaneously established distal tumors. Tumor inhibition was CD8(+) T-cell-dependent and was associated with increased CD8(+) T-cell infiltration in both treated and distal tumors, enhanced activation of tumor antigen-specific T cells in draining lymph nodes, and a reduction in regulatory T cells in treated tumors. These data suggest that local nanoparticle-anchored delivery of immuno-agonists represents a promising strategy to improve the therapeutic window and clinical applicability of highly potent but otherwise intolerable regimens of cancer immunotherapy. Cancer Res; 73(5); 1547-58. ©2012 AACR.

Membrane anchored immunostimulatory oligonucleotides for in vivo cell modification and localized immunotherapy.

Locally delivered immunomodulators are utilized to treat unresectable tumors and solid tumor resection sites to prevent local recurrence.1 Synthetic immunostimulatory oligonucleotides such as double-stranded RNA or unmethylated cytosine–guanosine motifs (CpG-ODNs) mimic molecular signatures of pathogens (viruses or bacteria, respectively) and trigger an immunostimulatory cascade including maturation, differentiation and proliferation of multiple host immune cells through pattern recognition receptors.2 As a result, these synthetic ODNs have been extensively studied as therapeutic agents for cancer and as vaccine adjuvants.2 However, a key element for the effectiveness of immunostimulatory ODNs is the close association of oligonucleotides with tumor antigen or tumor cells. For example, intratumoral/peritumoral CpG-ODN injections can lead to tumor regression in settings where intravenous CpG treatment has no effect.3 Also to this end, several CpG adjuvant studies indicated that co-delivery of CpG and antigens to the same antigen presenting cells (APC) significantly enhances antitumor responses.4 Two fundamental limitations of directly injecting ODNs into tumors are 1) relatively rapid loss of ODNs from the injection site due to their relatively low molecular weights and 2) lack of physical association between tumor cells and ODNs. We hypothesized that a membrane-interactive ODN that could spontaneously insert into cell membranes would in principle overcome both of these limitations, by prolonging ODN retention at tumor sites and more importantly, by providing a physical connection between tumor cells and ODNs.

T-bet-dependent NKp46+ innate lymphoid cells regulate the onset of TH17-induced neuroinflammation

The transcription factor T-bet has been associated with increased susceptibility to systemic and organ-specific autoimmunity, but the mechanism by which T-bet expression promotes neuroinflammation remains unknown. In this study, we demonstrate a cardinal role of T-bet-dependent NKp46+ innate lymphoid cells (ILCs) in the initiation of CD4+ TH17-mediated neuroinflammation. Loss of T-bet specifically in NKp46+ ILCs profoundly impaired the ability of myelin-reactive TH17 cells to invade central nervous system (CNS) tissue and protected the mice from autoimmunity. T-bet-dependent NKp46+ ILCs localized in the meninges and acted as chief coordinators of meningeal inflammation by inducing the expression of proinflammatory cytokines, chemokines and matrix metalloproteinases, which together facilitated T cell entry into CNS parenchyma. Our findings uncover a detrimental role of T-bet-dependent NKp46+ ILCs in the development of CNS autoimmune disease.