Christopher Garris

This pretty much sums up how academia works.

Fantastic study. With the recent resurgence in cancer vaccines, we should also consider that communication with cDC1 could be critical for response. Ken’s recent paper even shows potential long-term deficiencies in CD8 T cells activated through dressed cDC2. cDC1 remains king. 👑

Sigh… another “finalist” level proposal waitlisted again and likely won’t be funded. This keeps on happening and oddly, I’d prefer the hard reject as opposed to the repeated near misses; that way I wouldn’t keep wasting time and have more reason to course correct.

Very excited to share an amazing body of work now out in Nature Biotechnology!

For many years, the field of cancer immunology has recognized that immune-stimulatory dendritic cells, in particular cDC1, sit at the center of productive anti-tumor immunity. This is well conserved between mechanistic mouse models and humans, and high resolution single cell RNA seq studies have confirmed these cell states in a broad range of cancers.

These cells sit at the core of controlling and facilitating T cell responses and tumor recognition, illustrating how DCs “shepherd” T cells across their lifecycle. These T: DC interactions lie at the center of the Cancer Immunity Cycle. Yet, so far, we only have efficient methods to push on T cells for immunotherapy. Boosting DC responses has been more difficult where treatments need to more carefully balance the toxicity associated with immune activation and efficacy. These concerns, balancing toxicity and efficacy, have led to significant challenges in drug development

Here, we present a new approach enabled by catalytic advances in RNA therapeutics, where information gleaned from single-cell RNA seq cell states can be programmed into therapeutics to remodel the immune environment.

We find that mRNA encoding cDC1-related factors such as interferon regulatory factor 8 (IRF8) and the NFkB-inducing kinase (NIK) can activate antigen presentation and trigger inflammation of tumors by T cells, leading to tumor-immune rejection. Notably, sustained expression of IRF8 is needed for maintaining cDC1 lineage identity, and elegant prior studies demonstrate that enforced IRF8 expression can reprogram diverse cell types into cDC1-like cells. Likewise, we had previously identified NIK expression within IL-12-producing tumor DCs, and others showed that NIK deficiency impaired IL-12 production and the ability to stimulate CD8+ T cell responses. NIK lies downstream of CD40-based licensing, which is an essential step towards generating functional CD8+ T cells.

Here, we show that the application of these immune remodeling mRNAs (IR-mRNAs; either IRF8 or NIK) can synthetically activate antigen presentation and boost DC responses, triggering anti-tumor immunity. These IR-mRNAs shape the tumor microenvironment to be receptive to T cells, encouraging their accumulation and activity, further showing how DCs “shepherd” T cell responses. These can turn immune “cold” tumors “hot” and responsive to immune checkpoint blockade therapies.

Perhaps the most fascinating aspect of these studies is when IR-mRNA is delivered alongside antigen in vaccination settings. We find that robust CD8+ T cell responses are generated with IR-mRNA encoded immune adjuvants. This fits with the role of IRF8 and NIK supporting cDC1 responses, and raises the potential for a new class of cDC1-oriented immune therapeutics.

This was all part of an amazing collaboration between the Anderson Lab at MIT Koch Institute for Integrative Cancer Research and the Center for Systems Biology at Massachusetts General Hospital/Harvard Medical School. @kochinstitute @MGHPathology @MGHCSB @MGBResearchNews
#cancer #immunotherapy #vaccines #dendritic_cells #myeloid

Extra kudos to the lead authors, @akashh_gupta and @Das_Riddha now at @UHEngineering
The Article @NatureBiotech can be found here: nature.com/articles/s4158…
Lay Summaries can be found here: news.mit.edu/2026/new-appro… ; massgeneralbrigham.org/en/about/newsr…

Happy to share the most recent article from @MGHCSB, which is now published @natBME. In this article, we define an implantable perioperative immunotherapy that polarizes macrophages to anti-tumor phenotypes.
nature.com/articles/s4155…