Overexpression of the H3K36 histone methyltransferase NSD2 in t(4;14) multiple myeloma (MM) is an early, oncogenic event, and understanding its impact on genomic organisation and expression is relevant to understanding MM biology. We performed epigenetic, transcriptional and phenotypic profiling of the t(4;14) KMS11 myeloma cell line and its isogenic translocation knock out (TKO) to characterise the sequelae of NSD2 overexpression. We found a marked global impact of NSD2 on gene expression and DNA organisation implicating cell identity genes; notably the early lymphocyte regulator, LAIR1 and MM cell surface markers, including CD38, a classical marker of plasma cells which was reduced in TKO cells. Plasma cell transcription factors such as PRDM1, IRF4 and XBP1 were unaffected, suggesting a downstream direct gene effect of NSD2 on cell identity. Changes in cell surface markers suggest an altered surface immunophenotype. Our findings suggest a role for NSD2 in maintaining MM cell identity, with potential implications for future therapeutic strategies based on targeting of NSD2.

Understanding the evolution of the B cell response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants is fundamental to design the next generation of vaccines and therapeutics. We longitudinally analyze at the single-cell level almost 900 neutralizing human monoclonal antibodies (nAbs) isolated from vaccinated people and from individuals with hybrid and super hybrid immunity (SH), developed after three mRNA vaccine doses and two breakthrough infections. The most potent neutralization and Fc functions against highly mutated variants belong to the SH cohort. Repertoire analysis shows that the original Wuhan antigenic sin drives the convergent expansion of the same B cell germlines in vaccinated and SH cohorts. Only Omicron breakthrough infections expand previously unseen germ lines and generate broadly nAbs by restoring IGHV3-53/3-66 germ lines. Our analyses find that B cells initially expanded by the original antigenic sin continue to play a fundamental role in the evolution of the immune response toward an evolving virus.
Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.

ABSTRACT The unceasing interplay between SARS-CoV-2 and the human immune system has led to a continuous maturation of the virus and B cell response providing an opportunity to track their evolution in real time. We longitudinally analyzed the functional activity of almost 1,000 neutralizing human monoclonal antibodies (nAbs) isolated from vaccinated people, and from individuals with hybrid and super hybrid immunity (SH), developed after three mRNA vaccine doses and two breakthrough infections. The most potent neutralization and Fc functions against highly mutated variants, including BA.2.86, were found in the SH cohort. Despite different priming, epitope mapping revealed a convergent maturation of the functional antibody response. Neutralization was mainly driven by Class 1/2 nAbs while Fc functions were induced by Class 3/4 antibodies. Remarkably, broad neutralization was mediated by restored IGHV3-53/3-66 B cell germlines which, after heterogenous exposure to SARS-CoV-2 S proteins, increased their level of somatic hypermutations. Our study shows the resilience of the human immune system which restored previously expanded germlines and activated naïve B cells to broaden the antibody repertoire of antibodies to control future SARS-CoV-2 variants.

Post-infectious myalgic encephalomyelitis/chronic fatigue syndrome (PI-ME/CFS) is a disabling disorder, yet the clinical phenotype is poorly defined, the pathophysiology is unknown, and no disease-modifying treatments are available. We used rigorous criteria to recruit PI-ME/CFS participants with matched controls to conduct deep phenotyping. Among the many physical and cognitive complaints, one defining feature of PI-ME/CFS was an alteration of effort preference, rather than physical or central fatigue, due to dysfunction of integrative brain regions potentially associated with central catechol pathway dysregulation, with consequences on autonomic functioning and physical conditioning. Immune profiling suggested chronic antigenic stimulation with increase in naïve and decrease in switched memory B-cells. Alterations in gene expression profiles of peripheral blood mononuclear cells and metabolic pathways were consistent with cellular phenotypic studies and demonstrated differences according to sex. Together these clinical abnormalities and biomarker differences provide unique insight into the underlying pathophysiology of PI-ME/CFS, which may guide future intervention.
© 2024. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.

ABSTRACT Gonococcus (Gc), a bacterium resistant to most antibiotics causing more than 80 million cases of gonorrhea annually, is a WHO high priority pathogen. Recently, vaccine development prospects were boosted by reports that licensed meningococcus serogroup B (MenB) vaccines provided partial protection against Gc infection. To determine antigens responsible for cross-protection, memory B cells from 4CMenB vaccinated volunteers were single-cell sorted to identify antibodies that kill Gc in a bactericidal assay. Nine different antibodies, all deriving from the IGHV4-34 germline carrying unusually long HCDR3s, recognized the PorB protein, four recognized the lipooligosaccharide (LOS), and four unknown antigens. One of the PorB antibodies, tested in vivo, provided protection from Gc infection. The identification of PorB and LOS as key antigens of gonococcal and meningococcal immunity provides a mechanistic explanation of the cross-protection observed in the clinic and shows that isolating human monoclonal antibodies from vaccinees can be instrumental for bacterial antigen discovery.