Biology subjects

Chambers, B. J.

Publications and source records attributed to Chambers, B. J..

6 recordsLinked to original sources

bioRxiv2026

Intratumoral expression of JAML on NK cells is controlled by tumor microenvironment and MHC class I interaction

Junctional adhesion molecule-like (JAML) is an adhesion molecule known to promote T cell activation and T cell-mediated tumor rejection. In the current study, we show that JAML expression is enriched on mouse intratumoral NK cells compared with splenic NK cells. JAML+ NK cells were associated with tissue residency and co-expressed the immune checkpoints PD-1 and LAG3. JAML expression could be induced on splenic NK cells by IL-2 and further enhanced by IL-21. JAML levels were inversely correlated with inhibitory signaling, as NK cells expressing self-recognizing Ly49 receptors had reduced JAML expression, suggesting regulation of JAML expression by MHC class I molecules. Interaction with the JAML ligand CXADR also reduced JAML surface expression, indicating that tumor-mediated membrane stripping may represent a mechanism of immunoediting. Although JAML RNA transcripts were detectable in human NK cells, JAML protein was found only intracellularly. Together, these findings identify the JAML-CXADR interaction as a potential regulatory pathway in NK cell-mediated killing of tumors.

immunology↗

bioRxiv2026

Implantation failure linked to altered uterine NK cells in PCOS-like mice

Uterine NK (uNK) cells are essential for reproductive function, yet little is known how they are affected in polycystic ovary syndrome (PCOS), despite the strong association between PCOS and reproductive complications. We demonstrate that implantation failure coincides with distinct phenotypic alterations of uNK cells in a PCOS-like mouse model. Hyperandrogenism caused an increased influx of conventional NK (cNK) cells into the uterus, which contributed to an augmented uNK cell population, while tissue-resident NK (trNK) cells remained unchanged. Notably, CD69+ trNK cells were reduced and seemingly compensated by an upregulated expression of CD69 on cNK cells in the uterus. The maturation of uNK cells was disrupted and plausibly linked to an inability of cNK cells to convert into trNK cells. The inhibited maturation was associated with a reduced expression of the inhibitory receptor NKG2A, demonstrating an impaired education of uNK cells. This disruption of uNK cells could contribute to endometrial dysfunction and may be an underlying factor to reproductive comorbidities such as implantation failure, miscarriage and pre-eclampsia in PCOS.

immunology↗

bioRxiv2025

Development of DARPin T cell engagers for specific targeting of tumor-associated HLA/peptide complexes

The compromise between affinity and specificity in TCR-dependent targeting of HLA-restricted tumor-associated antigens presents a significant challenge in developing efficacious immunotherapies. As such, T cell engagers which circumvent these limitations are of particular interest. We have established a process to generate bispecific Designed Ankyrin Repeat Proteins (DARPins) that simultaneously target HLA-I molecules in complex with tumor-associated peptides and CD3{varepsilon}. High-affinity HLA-A*0201/NY-ESO1157-165-specific DARPins were isolated after only four rounds of in-vitro selection from naive DARPin libraries. Combining HLA-A*0201/NY-ESO1157-165-specific DARPins with a CD3{varepsilon}-specific DARPin created potent T cell engagers which elicited CD8+ T cell activation towards tumor targets with high peptide specificity, as confirmed by X-scanning mutagenesis and functional killing assays. The cryo-EM structure of a ternary DARPin/HLA-A*0201/NY-ESO1157-165 complex revealed a rigid and concave DARPin surface that binds to the entire length of the peptide-binding cleft, contacting both -helices and the peptide. The present results unveil promising immuno-oncotherapeutic approaches with the possibility of rapidly developing DARPins with high affinity and specificity to HLA/peptide targets that can be readily combined with a new generation of anti-CD3{varepsilon}-specific DARPins.

synthetic biology↗

bioRxiv2021

PD-1 expression on NK cells can be related to cytokine stimulation and tissue residency

Although PD-1 was shown to be a hallmark of T cells exhaustion, controversial studies have been reported on the role of PD-1 on NK cells. Here, we found by flow cytometry and single cell RNA sequencing analysis that PD-1 can be expressed on MHC class I-deficient tumor-infiltrating NK cells in vivo. We also demonstrate distinct alterations in the phenotype of PD-1-deficient NK cells which in part could be attributed to a decrease in tumor-infiltrating NK cells in PD-1-deficient mice. NK cells from PD-1-deficient mice exhibited a more mature phenotype which might reduce their capacity to migrate and kill in vivo. Finally, our results demonstrate that PD-L1 molecules in membranes of PD-1-deficient NK cells migrate faster than in NK cells from wildtype mice, suggesting that PD-1 and PD-L1 form cis interactions with each other on NK cells.

immunology↗

bioRxiv2021

GABAergic signaling in human and murine NK cells upon challenge with Toxoplasma gondii

Protective cytotoxic and proinflammatory cytokine responses by natural killer (NK) cells impact the outcome of infections by Toxoplasma gondii, a common parasite in humans and other vertebrates. However, T. gondii can also sequester within NK cells and downmodulate their effector functions. Recently, the implication of {gamma}-aminobutyric acid (GABA) signaling in infection and inflammation-related responses of mononuclear phagocytes and T cells has become evident. Yet, the role of GABAergic signaling in NK cells has remained unknown. Here, we report that human and murine NK cells synthesize and secrete GABA in response to infection challenge. Parasitized NK cells secreted GABA while activation stimuli, such as IL-12/IL-18 or parasite lysates, failed to induce GABA secretion. GABA secretion by NK cells was associated to a transcriptional upregulation of GABA synthesis enzymes (GAD65/67) and was abrogated by GAD-inhibition. Further, NK cells expressed GABA-A receptor subunits and GABA signaling regulators, with transcriptional modulations taking place upon challenge with T. gondii. Exogenous GABA and GABA-containing supernatants from parasitized dendritic cells (DCs) impacted NK cell function by reducing the degranulation and cytotoxicity of NK cells. Conversely, GABA-containing supernatants from NK cells enhanced the migratory responses of parasitized DCs. This enhanced DC migration was abolished by GABA-A receptor antagonism or GAD-inhibition and was reconstituted by exogenous GABA. Jointly, the data show that NK cells are GABAergic cells and that GABA hampers NK cell cytotoxicity in vitro. We hypothesize that GABA secreted by parasitized immune cells modulates the immune responses to T. gondii infection. Summary sentenceIn response to infection challenge, NK cells synthesize and secrete{gamma} -aminobutyric acid (GABA), which impacts NK cell and dendritic cell functions via GABA-A receptors.

immunology↗

bioRxiv2020

The MCMV immunoevasin gp40/m152 inhibits NKG2D receptor RAE-1γ by intracellular retention and cell surface masking

NKG2D is a crucial Natural Killer (NK) cell activating receptor, and the murine cytomegalovirus (MCMV) employs multiple immunoevasins in order to avoid NKG2D-mediated activation. One of the MCMV immunoevasins, gp40 (m152), downregulates the cell surface NKG2D ligand, RAE-1{gamma}, thus limiting NK cell activation. This study establishes the molecular mechanism by which gp40 retains RAE-1{gamma} in the secretory pathway. Using flow cytometry and pulse chase analysis, we demonstrate that gp40 retains RAE-1{gamma} in the early secretory pathway, and that this effect depends on the binding of gp40 to a host protein, TMED10, a member of the p24 protein family. We also show that the TMED10-based retention mechanism can be saturated, and that gp40 has a backup mechanism as it masks RAE-1{gamma} on the cell surface, blocking the interaction with the NKG2D receptor and thus NK cell activation. Summary statementMCMV immunoevasin gp40 inhibits the NKG2D-activating ligand RAE-1{gamma} by intracellular retention that depends on the p24 member TMED10, and additionally by masking it at the cell surface.

cell biology↗