Dendritic cells (DCs) have been thought to follow a life history, typified by Langerhans cells (LCs), with 2 major developmental stages: an immature stage that captures antigens in the periphery and a mature stage that presents those antigens in the lymphoid organs. However, a systematic assessment of the maturity of lymphoid organ DCs has been lacking. We have analyzed the maturity of the DC types found in the steady state in the spleen, lymph nodes (LNs), and thymus. The DCs that migrate into the iliac, mesenteric, mediastinal, or subcutaneous LNs from peripheral tissues were mature and therefore could not process and present newly encountered antigens. However, all the other DC types were phenotypically and functionally immature: they expressed low levels of surface major histocompatibility complex class II (MHC II) and CD86, accumulated MHC II in their endosomes, and could present newly encountered antigens. These immature DCs could be induced to mature by culture in vitro or by inoculation of inflammatory stimuli in vivo. Therefore, the lymphoid organs contain a large cohort of immature DCs, most likely for the maintenance of peripheral tolerance, which can respond to infections reaching those organs and mature in situ.
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http://dx.doi.org/10.1182/blood-2003-02-0513 | DOI Listing |
EMBO Mol Med
January 2025
Medical Clinic III for Oncology, Hematology, Immuno-Oncology and Rheumatology, University Hospital Bonn, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany.
Studying the human immune system in vivo is challenging and often not possible. Therefore, most human immunology studies have been predominantly confined to peripheral blood analyses, which by themselves have inherent limitations, as many immune reactions take place within tissues. For example, potent antibody responses that contribute to fighting infections and provide protection following vaccination require cellular interactions between B cells and T cells in specialized micro-anatomical structures called germinal centers, which are found in secondary lymphoid organs such as spleen, lymph nodes, and tonsils.
View Article and Find Full Text PDFbioRxiv
January 2025
Department of Chemistry, 409 McCormick Road, University of Virginia, Charlottesville, VA 22904.
Antibody production is central to protection against new pathogens and cancers, as well as to certain forms of autoimmunity. Antibodies often originate in the lymph node (LN), specifically at the extrafollicular border of B cell follicles, where T and B lymphocytes physically interact to drive B cell maturation into antibody-secreting plasmablasts. In vitro models of this process are sorely needed to predict aspects of the human immune response.
View Article and Find Full Text PDFCureus
January 2025
Internal Medicine, Hospital Senhora da Oliveira, Guimarães, PRT.
Sarcoidosis is a multisystem granulomatous disease of unknown etiology. Despite primarily affecting the lung, sarcoidosis can affect any organ, resulting in various clinical manifestations. We present a case of a 56-year-old man who developed thoracic pain over several months along with skin lesions.
View Article and Find Full Text PDFLancet
January 2025
Centre for Inflammatory Disease, Department of Immunology and Inflammation, Imperial College London, London, UK; Imperial College Renal and Transplant Centre, Imperial College Healthcare NHS Trust, Hammersmith Hospital, London, UK. Electronic address:
Background: In the UK, booster COVID-19 vaccinations have been recommended biannually to people considered immune vulnerable. We investigated, at a population level, whether the absence of detectable anti-SARS-CoV-2 spike protein IgG antibody (anti-S Ab) following three or more vaccinations in immunosuppressed individuals was associated with greater risks of infection and severity of infection.
Methods: In this prospective cohort study using UK national disease registers, we recruited participants with solid organ transplants (SOTs), rare autoimmune rheumatic diseases (RAIRDs), and lymphoid malignancies.
Cancer Lett
January 2025
. Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China. Electronic address:
Tertiary lymphoid structures (TLSs) are ectopic immune cell clusters formed in nonlymphoid tissues affected by persistent inflammation, such as in cancer and prolonged infections. They have features of the structure and function of secondary lymphoid organs, featuring central CD20+ B cells, surrounded by CD3+ T cells, CD21+ follicular dendritic cells, and CD68+ macrophages, with a complex vascular system. TLS formation is governed by lymphotoxin-α1β2, TNF, and chemokines like CCL19, CCL21, and CXCL13, differing from secondary lymphoid organ development in developing later in life at sites of chronic inflammation.
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