Biology subjects

James, O. J.

Publications and source records attributed to James, O. J..

4 recordsLinked to original sources

bioRxiv2025

Intraepithelial lymphocytes exhibit selective immunity to intestinal pathogens

Intraepithelial lymphocytes (IEL) are abundant, tissue-resident T cells critical for intestinal immune surveillance, yet their precise roles have remained elusive due to the lack of models enabling their selective genetic ablation. Here, we report the generation of Gzmb-Cre knock-in mice, that when crossed with inducible Diphtheria toxin receptor mice, allows targeted and inducible ablation of IELs without perturbing peripheral immunity. Using this model (referred to as IELiDTR), we demonstrate that IELs are dispensable for intestinal homeostasis, including epithelial architecture, barrier function and microbial composition. However, loss of IELs led to increased intestinal infection by Salmonella Typhimurium and Cryptosporidium parvum, but did not affect responses to Listeria monocytogenes infection or DSS colitis. Interestingly, IEL deficiency reduced fecundity of the intestinal nematode, Heligmosomoides polygyrus, despite unaltered worm burden, suggesting a permissive role in helminth colonization. These findings position IELs as evolutionary-tuned sentinels against co-evolved pathogens that can cause lethal diarrheal diseases, and establish the IELiDTR mouse as a vital genetic tool for dissecting IEL function in host-pathogen interactions in vivo.

immunology↗

bioRxiv2022

The Immunological Proteome Resource

The Immunological Proteome Resource (ImmPRes; http://immpres.co.uk/) is an open access public resource integrating proteomic data generated by large-scale mass-spectrometry analysis of murine hematopoietic populations. The initial focus is T lymphocytes and how their proteomes are shaped by immune activation, environment, and intracellular signalling pathways with an aim to expand it to B cells and innate immune cells. It is a multidisciplinary effort between immunology and mass spectrometry-based labs with the objective to help define an in-depth high-quality map of immune cell proteomes. Maintaining data reproducibility and integrity are a priority within the resource, thus there is an in-depth protocols section explaining in detail the sample processing and the mass spectrometry-based analysis. ImmPRes provides open access to proteomic datasets covering a wide range of murine leukocyte populations with analysis of copy numbers per cell of > 10,000 proteins, enabling new understanding of lymphocyte phenotypes. All data is accessible via a simple graphical interface that supports easy interrogation of the data and options to download data summaries and raw data files.

immunology↗

bioRxiv2021

Tissue environment, not ontogeny, defines intestinal intraepithelial T lymphocytes

Tissue-resident intestinal intraepithelial T lymphocytes (T-IEL) patrol the gut and have important roles in regulating intestinal homeostasis. T-IEL include both induced T-IEL, derived from systemic antigen-experienced lymphocytes, and natural IEL, which are developmentally targeted to the intestine. While the processes driving T-IEL development have been elucidated, the precise roles of the different subsets and the processes driving activation and regulation of these cells remain unclear. To gain functional insights into these enigmatic cells, we used high-resolution, quantitative mass spectrometry to investigate the proteomic landscape of the main T-IEL populations in the gut. Comparing the proteomes of induced T-IEL and natural T-IEL subsets, with naive CD8+ T cells from lymph nodes exposes the dominant effect of the gut environment over ontogeny on T-IEL phenotypes. Analyses of protein copy numbers of >7000 proteins in T-IEL reveal skewing of the cell surface repertoire towards epithelial interactions and checkpoint receptors; strong suppression of the metabolic machinery indicating a high energy barrier to functional activation; and changes in T cell antigen receptor signalling pathways reminiscent of chronically activated T cells. These novel findings illustrate how multiple input signals need to be integrated to regulate T-IEL function.

immunology↗

bioRxiv2020

Comprehensive proteomics analyses identify PIM kinases as key regulators of IL-15 driven activation of intestinal intraepithelial lymphocytes

Intestinal intraepithelial lymphocytes (IEL) are an abundant population of tissue-resident T cells that protect the gut from pathogens and maintain intestinal homeostasis. The cytokine IL-15 is transpresented by epithelial cells to IEL in complex with the IL-15 receptor chain (IL-15R). It plays essential roles both in maintaining IEL homeostasis, and in inducing IEL activation in response to epithelial stress. IL-15 overexpression also drives the gluten-induced enteropathy Coeliac disease, through cytotoxic activation of IEL. In order to better understand how IL-15 directly regulates both homeostatic and inflammatory functions of IEL, we set up quantitative proteomics of IL-15/R stimulated IEL. We reveal that high IL-15/R stimulation licenses cell cycle activation, upregulates the biosynthetic machinery in IEL, increases mitochondrial respiratory capacity and induces expression of cell surface immune receptors and adhesion proteins that potentially drive IEL activation. We find that high IL-15/R selectively upregulated the Ser/Thr kinases PIM1 and PIM2 and demonstrate that PIM1/2 are essential for IEL to proliferate, grow, and upregulate Granzyme B in response to high IL-15. Significantly, IEL from Coeliac disease patients express high levels of PIM kinases. These unexpected findings reveal PIM kinases to be key determinants of IEL responses to elevated levels of IL-15.

immunology↗