Boulay, J.-L. | Search bioRxiv

bioRxiv2026

Ancient IL-6-STAT5 signaling orchestrates inflammation in jawless vertebrates

Interleukin-6 (IL-6) is a central regulator of vertebrate immunity, yet its existence in jawless vertebrates has remained obscure because of extreme sequence divergence. The extant jawless vertebrates (lampreys and hagfish), which deploy variable lymphocyte receptors (VLRs) instead of immunoglobulins and T cell receptors, provide a unique window into the earliest interface between cytokines and adaptive immunity. Here, we identify IL-6-like genes in jawless vertebrates by combining computational structural comparisons, phylogenetic reconstruction, and conserved local and long-range synteny analyses. The encoded proteins adopt the canonical four-helix bundle characteristic of immune-related IL-6 family cytokines and align topologically with mammalian IL-6. In sea lamprey, three IL-6 paralogs show distinct leukocyte and tissue expression patterns and are differentially induced by pathogen-associated molecular patterns and skin injury, indicating early functional diversification of IL-6-mediated inflammatory responses. Stimulation of myeloid peritoneal leukocytes with recombinant lamprey IL-6 induces STAT5 phosphorylation and rapid upregulation of SOCS1/3 genes, consistent with an IL-6/STAT5/SOCS regulatory axis. These findings extend the repertoire of immune-related four-helix bundle cytokines to jawless vertebrates and indicate that IL-6-dependent inflammatory programs were already in place before the divergence of VLR-based and Ig/TCR-based adaptive immune systems in vertebrates.

immunology↗

bioRxiv2023

Enhancing anti-EGFRvIII CAR T cell therapy against glioblastoma with a paracrine SIRPγ-derived CD47 blocker

A major challenge for chimeric antigen receptor (CAR) T cell therapy against glioblastoma (GBM) is its immunosuppressive tumor microenvironment (TME), which is densely populated and supported by protumoral glioma-associated microglia and macrophages (GAMs). Targeting of CD47, a "dont-eat-me" signal overexpressed by tumor cells, disrupts the CD47-SIRP axis and induces GAM phagocytic function. However, antibody-mediated CD47 blockade monotherapy is associated with toxicity and low bioavailability in solid tumors. To overcome these limitations, we combined local CAR T cell therapy with paracrine GAM modulation for more effective elimination of GBM. To this end, we engineered a new CAR T cell against epidermal growth factor receptor variant III (EGFRvIII) that constitutively secretes a SIRP{gamma}-related protein (SGRP) with high affinity to CD47. Anti-EGFRvIII-SGRP CAR T cells eliminated EGFRvIII+ GBM in a dose-dependent manner in vitro and eradicated orthotopically xenografted EGFRvIII-mosaic GBM by locoregional application in vivo. This resulted in significant tumor-free long-term survival, followed by partial tumor control upon tumor re-challenge. The combination of anti-CD47 antibodies with anti-EGFRvIII CAR T cells failed to achieve a similar therapeutic effect, underscoring the importance of sustained paracrine GAM modulation. Multidimensional brain immunofluorescence microscopy and in-depth spectral flow cytometry on GBM-xenografted brains showed that anti-EGFRvIII-SGRP CAR T cells accelerated GBM clearance, increased CD68+ cell trafficking to tumor scar sites, and induced myeloid-mediated tumor cell uptake. Additionally, in a peripheral lymphoma mouse xenograft model, anti-CD19-SGRP CAR T cells had superior efficacy compared to conventional anti-CD19 CAR T cells. Validation on human GBM explants revealed that anti-EGFRvIII-SGRP CAR T cells had similar tumor-killing capacity to anti-EGFRvIII CAR monotherapy, but showed a slight improvement in maintenance of tumor-infiltrated CD14+ myeloid cells. Thus, local anti-EGFRvIII-SGRP CAR T cell therapy combines the potent antitumor effect of engineered T cells with the modulation of the surrounding innate immune TME, resulting in the additive elimination of bystander EGFRvIII- tumor cells in a manner that overcomes major mechanisms of CAR T cell therapy resistance, including tumor innate immune suppression and antigen escape.

cancer biology↗