Microbial products, such as CpG DNA and LPS, enhance class II MHC (MHC-II) expression and Ag presentation by dendritic cells, but this effect does not occur with macrophages and is largely unexplored in B cells. Although MHC-II expression is influenced by transcriptional regulation, which is governed by class II transactivator (CIITA) in all cells, microbial products enhance MHC-II expression by dendritic cells in part by increasing MHC-II protein stability. In this study, we show that the CpG-induced increase in MHC-II expression by B lymphocytes is not due to protein stabilization or changes in CIITA expression or activity, but instead is due to increased stability of MHC-II mRNA. This CIITA-independent mechanism adds a new layer of complexity to regulation of MHC-II and may increase T cell help for B cell Ab responses to microbial or vaccine Ags.
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http://dx.doi.org/10.4049/jimmunol.171.5.2320 | DOI Listing |
Cell Rep
January 2025
Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA. Electronic address:
Tumor-draining lymph node dendritic cells (DCs) are poor stimulators of tumor antigen-specific CD4 T cells; however, the mechanism behind this defect is unclear. We now show that, in tumor-draining lymph node DCs, a large proportion of major histocompatibility complex class II (MHC-II) molecules retains the class II-associated invariant chain peptide (CLIP) fragment of the invariant chain bound to the MHC-II peptide binding groove due to reduced expression of the peptide editor H2-M and enhanced activity of the CLIP-generating proteinase cathepsin S. The net effect of this is that MHC-II molecules are unable to efficiently bind antigenic peptides.
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December 2024
Emory University School of Medicine, Atlanta, GA, USA.
Background: Changes in neuroinflammatory tone have been shown to modulate neuroimmune responses to Alzheimer's disease (AD) pathology and shape disease outcomes, however, extrinsic factors that modify neuroimmune activation remain poorly understood. The gut microbiome is one such factor, with the ability to shape peripheral and central immune activation, as well as AD pathologies. AD patients display unique changes in microbiome composition, however, the link between specific AD-associated gut bacteria, neuroinflammatory tone, and AD outcomes remains to be elucidated.
View Article and Find Full Text PDFFood Funct
January 2025
State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang 330047, China.
Sci Rep
December 2024
Department of Biomedical Sciences and Pathobiology, Virginia Tech, Blacksburg, VA, USA.
Double negative T (DNT) cells are a unique subset of CD3 + TCRαβ + T lymphocytes that lack CD4, CD8, or NK1.1 expression and constitute 3-5% of the total T cell population in C57BL/6 mice. They have increasingly gained recognition for their novel roles in the immune system, especially under autoimmune conditions.
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December 2024
State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China.
SR21, a kind of eukaryotic heterotrophic organism rich in unsaturated fatty acids, is an emerging microbial alternative to fish oil. The dietary inclusion of 15% SR21 was optimal for the growth performance of zebrafish. Previous studies demonstrated that fructose-1,6-bisphosphate aldolase (FBA) of is a valuable broad-spectrum antigen against various pathogens in aquaculture (e.
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