Immunological competence declines progressively with age, resulting in increased susceptibility of the elderly to infection and impaired responses to vaccines. Underlying mechanisms remain largely obscure as they have been related to complex, individual systemic immune properties that are challenging to investigate. In this study, we explored age-related changes in human immunity during a primary virus infection experimentally induced by immunization with live-attenuated yellow fever (YF) vaccine. Applying detailed serology, advanced FACS analysis, and systems biology, we discovered that aged subjects developed fewer neutralizing Abs, mounted diminished YF-specific CD8(+) T cell responses, and showed quantitatively and qualitatively altered YF-specific CD4(+) T cell immunity. Among numerous immune signatures, low in vivo numbers of naive CD4(+) recent thymic emigrants and peripheral dendritic cells correlated well with reduced acute responsiveness and altered long-term persistence of human cellular immunity to YF vaccination. Hence, we reveal in this article that essential elements of immune responses such as recent thymic emigrants and dendritic cells strongly relate to productive immunity in the elderly, providing a conceivable explanation for diminished responsiveness to vaccination with neoantigens and infection with de novo pathogens in the aged population.
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http://dx.doi.org/10.4049/jimmunol.1500598 | DOI Listing |
Cells
December 2024
Department of Rheumatology and Inflammation Research, Institute of Medicine, University of Gothenburg, 41346 Gothenburg, Sweden.
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Hematopoietic Stem Cell Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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View Article and Find Full Text PDFDev Biol
December 2024
University of Edinburgh, Institute for Immunology and Infection Research, Edinburgh, United Kingdom. Electronic address:
Chickens are renowned as a model for embryogenesis but have also been responsible for crucial advances in virology, cancer research and immunology. However, chickens are best known as a major source of animal protein for human nutrition, with roughly 80 billion chickens alive each year supplying meat and eggs, the vast majority part of a global poultry industry. As a result, avian immunology been studied intensively for over 60 years, and it has become clear that a major genetic locus in chickens determining resistance to infectious disease and response to vaccines is the major histocompatibility complex (MHC).
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December 2024
Department of Pediatrics, Institute of Health Sciences, Division of Pediatric Immunology and Allergy and Master's/Doctoral Program, Jeffrey Modell Primary Immunodeficiency Diagnosis Center, Işıl Barlan Translational Medicine Center, Immunodeficiency Application and Research Center, Faculty of Medicine, Marmara University, Istanbul, Turkey.
Open Biol
October 2024
Department of Surgery, University of Alberta, Edmonton, AB, Canada.
Immunologic self-tolerance involves signals from co-inhibitory receptors. Several T cell co-inhibitors, including PD-1, are expressed upon activation, whereas CD5 and BTLA are expressed constitutively. The relationship between constitutively expressed co-inhibitors and when they are needed is unknown.
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