Hair follicles (HFs) enjoy a relative immune privilege (IP) that is characterized by downregulation of major histocompatibility complex (MHC) class I and local expression of potent immunosuppressants. Normally, natural killer (NK) cells attack cells with absent/low MHC class I expression. However, because few perifollicular NK cells are found around healthy human anagen HFs, we asked how HFs escape from NK cell attack. This study suggests that this happens via an active NK cell suppression. Alopecia areata (AA), an organ-specific autoimmune disease thought to result from a collapse of HF-IP, in contrast, shows striking defects in NK cell inhibition/containment. We show that the NK cell inhibitor macrophage migration inhibitory factor is strongly expressed by the HF epithelium, and very few CD56(+)/NKG2D(+) NK cells are observed in and around normal anagen HFs compared to AA with prominent aggregations of CD56(+)/NKG2D(+) NK around AA-HFs. By flow cytometry, many fewer NK function-activating receptors (NKG2D, NKG2C) and significantly more killer cell Ig-like receptors-2D2/2D3 were found to be expressed on peripheral blood CD56(+) NK cells of healthy controls than on those of AA patients. In addition, only weak immunoreactivity for MHC class I chain-related A gene was observed in normal anagen HFs compared to AA. To our knowledge, this defect is previously unreported and must be taken into account in AA pathogenesis and its management.
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http://dx.doi.org/10.1038/sj.jid.5701183 | DOI Listing |
BMC Immunol
January 2025
Laboratoire Génomique, Bioinformatique, et Chimie Moléculaire, Conservatoire National des Arts et Métiers, 2 rue Conté 75003, Paris, EA7528, France.
Introduction: We have reanalyzed the genomic data from the International Collaboration for the Genomics of HIV (ICGH), focusing on HIV-1 Elite Controllers (EC).
Methods: A genome-wide association study (GWAS) was performed, comparing 543 HIV-1 EC individuals with 3,272 uninfected controls (CTR) of European ancestry. 8 million single nucleotide polymorphisms (SNPs) and HLA class I and class II gene alleles were imputed to compare EC and CTR.
Commun Biol
January 2025
Department of Medicine, Universite de Montreal, Montreal, QC, Canada.
Severe COVID-19 can trigger a cytokine storm, leading to acute respiratory distress syndrome (ARDS) with similarities to superantigen-induced toxic shock syndrome. An outstanding question is whether SARS-CoV-2 protein sequences can directly induce inflammatory responses. In this study, we identify a region in the SARS-CoV-2 S2 spike protein with sequence homology to bacterial super-antigens (termed P3).
View Article and Find Full Text PDFJ Immunother Cancer
January 2025
Department of Pathology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA
Background: Concurrent (STK11, KL) mutant non-small cell lung cancers (NSCLC) do not respond well to current immune checkpoint blockade therapies, however targeting major histocompatibility complex class I-related chain A or B (MICA/B), could pose an alternative therapeutic strategy through activation of natural killer (NK) cells.
Methods: Expression of NK cell activating ligands in NSCLC cell line and patient data were analyzed. Cell surface expression of MICA/B in NSCLC cell lines was determined through flow cytometry while ligand shedding in both patient blood and cell lines was determined through ELISA.
Front Immunol
January 2025
Norwegian College of Fishery Science, Faculty of Bioscience, Fisheries and Economics, University of Tromsø - The Arctic University of Norway, Tromsø, Norway.
Non-classical MHC class I genes which, compared to classical MHC class I, are typically less polymorphic and have more restricted expression patterns are attracting interest because of their potential to regulate immune responses to various pathogens. In salmonids, among the numerous non-classical MHC class I genes identified to date, L lineage genes, including Sasa- and , are differentially induced in response to microbial challenges. In the present study, we show that while transcription of both and are induced in response to SAV3 infection the transcriptional induction patterns are distinct for each gene.
View Article and Find Full Text PDFiScience
January 2025
Sana Biotechnology Inc., 1 Tower Place, South San Francisco, CA, USA.
Hypoimmune (HIP) allogeneic cell therapeutics hold the promise to allow off-the-shelf treatments for a broad patient population. Our HIP approach includes the depletion of major histocompatibility complex (MHC) class I and II molecules and the overexpression of Cd47. Here, we report the engineering of HIP mice that stably exhibit the HIP phenotype in all cell types.
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