Biology subjects

Hayday, A. C.

Publications and source records attributed to Hayday, A. C..

4 recordsLinked to original sources

bioRxiv2026

Atypical T cell receptor signalling permits distinct gut gd T cell responses to healthy versus dysregulated tissues

Intraepithelial lymphocytes (IEL) are conserved across vertebrates and commonly enriched in {gamma}{delta} T cells. Several such {gamma}{delta} IELs depend upon homeostatic interactions of their T cell receptors (TCRs) with butyrophilin-like (BTNL) proteins expressed by healthy enterocytes and colonocytes. What limits such interactions from inducing full-blown T cell activation which would disrupt barrier integrity is unknown. Here, using primary IEL, we describe an atypical TCR signalling pathway (Signal 1) downstream of BTNL engagement, that fails to activate either global protein synthesis or cell proliferation. This attenuation could be overcome by provision of a co-stimulator (Signal 2) or inflammatory cytokines (Signal 3). It could also be relieved cell-intrinsically by blocking a lipid phosphatase. These findings can, at least in part, explain how extrinsic and intrinsic regulators permit IEL to be constitutively active in healthy tissues and additionally make full-blown responses to adaptive TCR ligands during tissue perturbation.

immunology↗

bioRxiv2025

BATF3 controls the homeostatic maintenance and function of innate-like γδ T cells

{gamma}{delta} T cells compose an evolutionarily conserved lineage of lymphocytes, with both adaptive- and innate-like characteristics, contributing to tissue homeostasis, immune surveillance, and rapid responses to stress and infection. While their functional diversity and tissue-specific roles are tightly regulated by transcriptional networks, the underlying molecular mechanisms remain incompletely understood. The transcription factor basic leucine zipper ATF-like transcription factor 3 (BATF3) plays a central role in the development of conventional type 1 dendritic cells (cDC1s). Here, we unveil BATF3 as a critical cell-intrinsic regulator of the homeostasis, functional specialization, and tissue distribution of {gamma}{delta} T cells. Batf3-deficient mice display an altered composition of {gamma}{delta} T cell subsets, with a marked decrease in the numbers of innate-like {gamma}{delta} T cells across multiple organs when compared to their wild-type counterparts, independently of cDC1s. Loss of BATF3 impacts not only cell survival but also IL-17 production after {gamma}{delta} T cells complete their thymic development. Mechanistically, Batf3-deficient innate-like {gamma}{delta} T cells exhibit transcriptional changes that disrupt pathways governing actin cytoskeleton remodelling, immunological synapse organization and cellular identity. Notably, Batf3-deficient mice present decreased survival in a viral infection model highly dependent on innate-like {gamma}{delta} T cells. Together, our findings uncover a previously unrecognized BATF3-dependent pathway that controls {gamma}{delta} T cell morphology and function, profoundly impacting their biology.

immunology↗

bioRxiv2022

Improved memory CD8 T cell response to delayed vaccine boost is associated with a distinct molecular signature.

Although the prime/boost interval can impact vaccine responses, the criteria for deciding its time length are poorly defined. To address this, we examined CD8 T cell responsiveness to boost in a BALB/c mouse model of intramuscular (i.m.) vaccination by priming with HIV-1 gag-encoding Chimpanzee adenovector, and boosting with HIV-1 gag-encoding Modified Vaccinia virus Ankara. We found that boost was more effective at day(d)100 than at d30 post-prime, as evaluated at d45 post-boost by multi-lymphoid organ assessment of gag-specific CD8 T cell frequency, CD62L-expression (as a guide to memory status) and in vivo killing. RNA-sequencing of splenic gag-primed CD8 T cells at d100 revealed a quiescent, but highly responsive signature, that trended toward a central memory (CD62L+) phenotype. Interestingly, gag-specific CD8 T cell frequency selectively diminished in the blood at d100, relative to the spleen, lymph nodes and bone marrow. These results move forward the rational design of prime/boost intervals.

immunology↗

bioRxiv2021

Impact of the B.1.1.7 variant on neutralizing monoclonal antibodies recognizing diverse epitopes on SARS-CoV-2 Spike

The interaction of the SARS-CoV-2 Spike receptor binding domain (RBD) with the ACE2 receptor on host cells is essential for viral entry. RBD is the dominant target for neutralizing antibodies and several neutralizing epitopes on RBD have been molecularly characterized. Analysis of circulating SARS-CoV-2 variants has revealed mutations arising in the RBD, the N-terminal domain (NTD) and S2 subunits of Spike. To fully understand how these mutations affect the antigenicity of Spike, we have isolated and characterized neutralizing antibodies targeting epitopes beyond the already identified RBD epitopes. Using recombinant Spike as a sorting bait, we isolated >100 Spike-reactive monoclonal antibodies from SARS-CoV-2 infected individuals. ~45% showed neutralizing activity of which ~20% were NTD-specific. None of the S2-specific antibodies showed neutralizing activity. Competition ELISA revealed that NTD-specific mAbs formed two distinct groups: the first group was highly potent against infectious virus, whereas the second was less potent and displayed glycan-dependant neutralization activity. Importantly, mutations present in B.1.1.7 Spike frequently conferred resistance to neutralization by the NTD-specific neutralizing antibodies. This work demonstrates that neutralizing antibodies targeting subdominant epitopes need to be considered when investigating antigenic drift in emerging variants.

immunology↗