Biology subjects

Wall, E. C.

Publications and source records attributed to Wall, E. C..

6 recordsLinked to original sources

bioRxiv2024

The CSF transcriptome in pneumococcal meningitis reveals compartmentalised host inflammatory responses associated with mortality.

AbstractO_ST_ABSBackgroundC_ST_ABSPneumococcal meningitis (PM) has persistently poor clinical outcomes, especially in sub- Saharan Africa. To better characterise the inflammatory response and identify factors associated with mortality we compared paired peripheral blood and cerebrospinal fluid (CSF) transcriptomes before the initiation of antibiotics in Malawian adults with proven PM. ResultsBlood transcriptional profiles were obtained in 28 patients with PM, with simultaneous paired with CSF profiles available for 13 patients. 15/28 (52%) patients died. Comparison of the transcriptome between CSF and blood compartments showed upregulation of 2293 differentially expressed genes in CSF and 909 in blood; enriched pathways in CSF included inflammasome activity and neutrophil migration/activation in the CSF, contrasting with enrichment for pathways including platelet and endothelial activation, cell cycle, cytokine release and oxidative stress in the blood transcriptome. Comparison of CSF profiles between survivors and non-survivors revealed 1829 differentially expressed genes, non- survivor CSF was enriched for multiple innate inflammatory pathways, including IL-17A and Type 1 interferons and proteolysis. In contrast, minimal transcriptomic differences between outcome groups were detected in blood. ConclusionInflammation in PM is characterised by compartmentalised responses in blood and CSF. Poorer outcomes are associated with an dysregulated innate immune host response to S. pneumoniae in the CSF compartment.

immunology↗

bioRxiv2024

The Streptococcus pneumoniae transcriptome in patient cerebrospinal fluid identifies novel virulence factors required for meningitis

To better understand Streptococcus pneumoniae pathogenesis we performed RNA sequencing on cerebrospinal fluid (CSF) from meningitis patients to identify bacterial genes expressed during invasion of the central nervous system. Comparison to transcriptome data for serotype 1 S. pneumoniae cultured in ex vivo human CSF defined a subset of 57 genes with high expression during human meningitis. Deletion of two of the most highly expressed genetic loci, bgaA (encodes for a {beta}-galactosidase) or the SP_1801-5 putative stress response operon, resulted in S. pneumoniae strains still able to transmigrate the blood brain barrier but which were more susceptible to complement opsonisation and unable to maintain brain infection in a murine meningitis model. In 1144 meningitis patients, infection with bgaA containing S. pneumoniae strains was associated with a higher mortality (22% versus 14% p=0.02). These data demonstrate that direct bacterial RNAseq from CSF can identify previously undescribed S. pneumoniae virulence factors required for meningitis pathogenesis.

microbiology↗

bioRxiv2024

Accurate evaluation of live-virus microneutralisation for SARS-CoV-2 variant JN.1

Emerging SARS-CoV-2 variants require rapid assessments of pathogenicity and evasion of existing immunity to inform policy. A crucial component of these assessments is accurate estimation of serum neutralising antibody titres using cultured live virus isolates. Here, we report our updated culture methods for Omicron sub-variant JN.1 using Caco-2 cells and the subsequent evaluation of neutralising antibody titres (nAbTs) in recipients of BNT162b2-XBB.1.5 monovalent and the Ancestral/BA.5 containing bivalent vaccines. We compared culture of JN.1 in either Vero V1 cells or Caco-2 cells, finding culture in Vero V1 either resulted in low-titre stocks or induced crucial mutations at the Spike furin cleavage site. Using the sequence-clean culture stocks generated in Caco-2 cells, we assessed serum samples from 71 healthy adults eligible for a COVID-19 vaccination given as a 5th dose booster: all participants had detectable nAbs against JN.1 prior to vaccination, with baseline/pre-existing nAbTs between both vaccine groups comparable (p = 0.240). However, nAbTs against JN.1 post-vaccination were 2.6-fold higher for recipients of the monovalent XBB1.5 vaccine than the BA.4/5 bivalent vaccine (p<0.001). Regular re-appraisal of methods involved in the evaluation of new variants is required to ensure robust data are used to underpin crucial severity assessments as variants arise and vaccine strain selection decisions.

microbiology↗

bioRxiv2023

Dichotomy of neutralizing antibody, B cell and T cell responses to SARS-CoV-2 vaccination and protection in healthy adults

Heterogeneity in SARS-CoV-2 vaccine responses is not understood. Here, we identify four patterns of live-virus neutralizing antibody responses: individuals with hybrid immunity (with confirmed prior infection); rare individuals with low responses (paucity of S1-binding antibodies); and surprisingly, two further groups with distinct serological repertoires. One group - broad responders - neutralize a range of SARS-CoV-2 variants, whereas the other - narrow responders - neutralize fewer, less divergent variants. This heterogeneity does not correlate with Ancestral S1-binding antibody, rather the quality of the serological response. Furthermore, IgDlowCD27-CD137+ B cells and CCR6+ CD4+ T cells are enriched in broad responders before dose 3. Notably, broad responders have significantly longer infection-free time after their third dose. Understanding the control and persistence of these serological profiles could allow personalized approaches to enhance serological breadth after vaccination.

immunology↗

bioRxiv2019

Both the inflammatory response and clinical outcome differ markedly between adults with pneumococcal and meningococcal meningitis in a high HIV-1 prevalent setting in sub-Saharan Africa

Outcomes from pneumococcal meningitis (PM) are worse than meningococcal meningitis (MM), particularly in settings with high HIV-1 prevalence, but the reasons are unknown. We compared inflammatory responses between PM and MM in Malawian adults. As compared to MM (n=27, 67% HIV-infected, mortality 11%), patients with PM (n=440, 84% HIV-infected, mortality 54%) were older, had strikingly lower CSF WCC, higher pro-inflammatory cytokine concentrations and higher mortality. PM is characterized by significantly lower CSF WCC, but greater inflammation and higher mortality compared to MM. Mechanistic understanding of blunting of the CSF leukocyte response in PM in-vivo is required.

immunology↗

bioRxiv2018

Cerebrospinal fluid transcriptional analyses reveals upregulation of IL-17, Type 1 interferon transcriptional pathways and neutrophil persistence genes associated with increased mortality from pneumococcal meningitis in adults

BackgroundImproving outcomes from pneumococcal meningitis (PM), particularly in populations with high HIV prevalence, requires better understanding of host inflammatory responses to infection.\n\nMethodsWe compared the transcriptome in pre-antibiotic cerebrospinal fluid (CSF) and blood from Malawian adults with PM using RNA sequencing. We used network analyses and cellular/process deconvolution of the transcriptome to identify important patho-physiological associations with outcome.\n\nFindingsBlood transcriptional profiles were obtained in 28 patients (21 HIV co-infected; median age 33 years [26-66]; median CSF WCC 28 cells/mm3 [0-3660]; median bacterial load 4.7x106 copies/ml CSF [671-2x109]; in-hospital mortality 64%), paired CSF profiles were obtained in 13. Marked differences in gene expression by outcome were confined to the CSF. In non-survivors, differentially expressed genes in the CSF were co-correlated in a network of pro-inflammatory gene-clusters enriched for collagen degradation and platelet degranulation. In contrast, CSF gene expression networks from surviving patients were dominated by DNA repair, transcriptional regulation and immunological signalling. CSF expression of gene response-modules for IL-17, Type 1 interferons and IL-10 were enriched in non-survivors, expression of cell-specific response-modules did not differ by outcome. However, genes for neutrophil chemotaxis and persistence were highly over-expressed in non-survivors.\n\nInterpretationThese data suggest poor outcome in PM is associated with over-expression of IL-17 and T1-IFN associated pro-inflammatory responses in the CSF and suggest a role for neutrophil-mediated inflammation. These responses are unlikely to be effected by current adjunctive treatments. Improving poor outcomes from PM will require better-targeted interventions.\n\nFundingAcademy of Medical Sciences (UK), Wellcome Trust (UK) (089671/B/09/Z)

immunology↗