In addition to regulating immune responses by producing antibodies that confer humoral immunity, B cells can also affect these responses by producing cytokines. How B cells participate in the clearance of pathogenic infections functions other than the production of pathogen-specific antibodies is still largely unknown. Marginal zone (MZ) B cells can quickly respond to bacterial invasion by providing the initial round of antibodies. After a bloodborne bacterial infection, neutrophils promptly migrate to the MZ. However, the mechanisms regulating neutrophil accumulation in the MZ during the initial phase of infection also remain obscure. Here, we found that MZ B cell-deficient mice are more susceptible to systemic () infection compared with wildtype mice. The expression levels of interleukin (IL)-6 and CXCL1/CXCL2 in MZ B cells increased significantly in mice at 3-4 h after infection with , then decreased at 24 h post-infection. After systemic infection, splenic neutrophils express increased CXCR2 levels. Our results from confocal microscopy imaging of thick-section staining demonstrate that neutrophils in wildtype mice form cell clusters and are in close contact with MZ B cells at 3 h post-infection. This neutrophil cluster formation shortly after infection was diminished in both MZ B cell-deficient mice and IL-6-deficient mice. Blocking the action of CXCL1/CXCL2 by injecting anti-CXCL1 and anti-CXCL2 antibodies 1 h before infection significantly suppressed the recruitment of neutrophils to the MZ at 3 h post-infection. Compared with peptidoglycan stimulation alone, peptidoglycan stimulation with neutrophil co-culture further enhanced MZ B-cell activation and differentiation. Using a Förster resonance energy transfer by fluorescence lifetime imaging (FLIM-FRET) analysis, we observed evidence of a direct interaction between neutrophils and MZ B cells after peptidoglycan stimulation. Furthermore, neutrophil depletion in mice resulted in a reduced production of -specific immunoglobulin (Ig)M at 24 h post-infection. Together, our results demonstrate that MZ B cells regulate the rapid neutrophil swarming into the spleen during the early phase of systemic infection. Interaction with neutrophils assists MZ B cells with their differentiation into IgM-secreting cells and contributes to the clearance of systemic bacterial infections.
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http://dx.doi.org/10.3389/fimmu.2021.636818 | DOI Listing |
Shock
December 2024
Department of Emergency and Critical Care Medicine, Lianyungang Clinical College of Nanjing Medical University, Lianyungang 222000, Jiangsu, China.
Background: The relationship between the partial pressure of oxygen in arterial blood (PaO2) and the prognosis of sepsis patients, and its potential variation over time, remains unclear. The optimal PaO2 range for sepsis patients has always been a contentious issue, with no consensus. We aimed to explore the association between different levels of PaO2 exposure over time and the 28-day mortality of sepsis patients, and to identify the optimal PaO2 range for sepsis patients within a specific time frame.
View Article and Find Full Text PDFPlant Signal Behav
December 2025
School of Medical Technology, Chongqing Three Gorges Medical College, Chongqing, China.
The most damaging disease affecting citrus globally is Huanglongbing (HLB), primarily attributed to the infection by ' asiaticus' (Las). Based on comparative transcriptome data, two cellulose synthase (CESA) genes responsive to Las infection induction were screened, and one gene cloned with higher differential expression level was selected and named . we verified the interaction between CsCESA1 and citrus exopolysaccharide 2 (CsEPS2) proteins.
View Article and Find Full Text PDFJAMA Netw Open
December 2024
School of Pharmacy, University of Maryland, Baltimore.
Importance: Initiating effective therapy early is associated with improved survival among patients hospitalized with gram-negative bloodstream infections; furthermore, providing early phenotype-desirable antimicrobial therapy (PDAT; defined as receipt of a β-lactam antibiotic with the narrowest spectrum of activity to effectively treat the pathogen's phenotype) is crucial for antimicrobial stewardship. However, the timing of targeted therapy among patients hospitalized with gram-negative bloodstream infections is not well understood.
Objective: To compare the clinical outcomes between patients who were hospitalized with Enterobacterales bloodstream infections receiving early vs delayed PDAT.
Intensive Care Med
December 2024
Department of Anaesthesiology, Critical Care and Pain, Tata Memorial Hospital, Homi Bhabha National Institute, Mumbai, Maharashtra, India.
Purpose: To generate consensus and provide expert clinical practice statements for the management of adult sepsis in resource-limited settings.
Methods: An international multidisciplinary Steering Committee with expertise in sepsis management and including a Delphi methodologist was convened by the Asia Pacific Sepsis Alliance (APSA). The committee selected an international panel of clinicians and researchers with expertise in sepsis management.
We identified Prototheca spp. microalga in ocular samples of a cat in Spain with nontreatable endogenous endophthalmitis. Within 2 years, the eye lesions progressively worsened and neurologic signs appeared, suggesting systemic spread of the infection.
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