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Phosphatidylinositol 3' OH kinase (PI3K) signaling and FOXO transcription factors play opposing roles at several B cell developmental stages. We show here abundant nuclear FOXO1 expression in the proliferative compartment of the germinal center (GC), its dark zone (DZ), and PI3K activity, downregulating FOXO1, in the light zone (LZ), where cells are selected for further differentiation. In the LZ, however, FOXO1 was expressed in a fraction of cells destined for DZ reentry. Upon FOXO1 ablation or induction of PI3K activity, GCs lost their DZ, owing at least partly to downregulation of the chemokine receptor CXCR4. Although this prevented proper cyclic selection of cells in GCs, somatic hypermutation and proliferation were maintained. Class switch recombination was partly lost due to a failure of switch region targeting by activation-induced deaminase (AID).
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http://dx.doi.org/10.1016/j.immuni.2015.10.021 | DOI Listing |
Zhonghua Bing Li Xue Za Zhi
September 2025
Department of Pathology, Clinical Oncology School of Fujian Medical University/Fujian Cancer Hospital, Fuzhou 350014, China.
To explore the clinical features, histopathological morphology, and differential diagnosis of lymphoepithelioma-like carcinoma with abnormal expression of follicular dendritic cell markers. From 2020 to 2021, 4 cases of lymphoepithelioma-like carcinoma with abnormal expression of follicular dendritic cell markers diagnosed in Fujian Cancer Hospital (2 cases) and the Second Affiliated Hospital of Fujian Medical University (2 cases) were collected. Different ancillary procedures such as HE, special stains, immunohistochemistry, and in situ hybridization techniques were used to assess the histopathological features and immunophenotypes.
View Article and Find Full Text PDFAm J Respir Crit Care Med
September 2025
University of Iowa Roy J and Lucille A Carver College of Medicine, Iowa City, Iowa, United States;
J Integr Neurosci
August 2025
Institute of Neuroscience and Third Affiliated Hospital, Zhengzhou University, 450052 Zhengzhou, Henan, China.
Background: Germinal matrix hemorrhage (GMH) is a common complication of premature infants with lifelong neurological consequences. Inflammation-mediated blood-brain barrier (BBB) disruption has been implicated as a main mechanism of secondary brain injury after GMH. The cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS)-stimulator of interferon genes (STING) pathway plays a crucial role in inflammation, yet its involvement in GMH pathophysiology remains unclear.
View Article and Find Full Text PDFFront Immunol
September 2025
Bacterial Scientific Area, GSK Vaccine, Siena, Italy.
Background: Protein-polysaccharide conjugate vaccines rely on the induction of T-cell-dependent responses that support germinal center (GC) reactions to potentiate the expansion of antigen-specific memory B-cell (MBC) populations and high-avidity antibody responses. The effects of adjuvants on B-cell and antibody responses are well described for protein antigens but remain largely unexplored for conjugated polysaccharidic antigens.
Methods: We assessed the effects of five adjuvants present in licensed vaccines (AS01, AS03, AS04, and aluminum hydroxide [Alum]) or under clinical evaluation (AS37) on the magnitude and quality of antigen-specific antibody responses and local/systemic B-cell responses.
Ugeskr Laeger
September 2025
Ortopædkirurgisk Afdeling, Københavns Universitetshospital - Holbæk Sygehus.
An 84-year-old man with a history of amputation and follicular lymphoma developed a non-healing ulcer on his stump, initially diagnosed as a pressure ulcer cause by the clinic and lack of B-symptoms. Despite wound care, the lesion worsened. A biopsy revealed de novo diffuse large B-cell lymphoma (DLBCL), non-germinal center subtype.
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