Biology subjects

Turner, J. S.

Publications and source records attributed to Turner, J. S..

13 recordsLinked to original sources

bioRxiv2026

Hydrocephalus caused by Katnip deletion is linked to increased ciliogenesis and reduced proliferation of neuroprogenitor cells

BackgroundKATNIP (Katanin-interacting protein), also known as KIAA0556, is one of the human genes with pathogenic variants linked to Joubert syndrome, an archetypal neurodevelopmental ciliopathy. KATNIP is a scaffolding protein with a critical role in ciliogenesis. In this study, we characterized the ciliopathy phenotypes due to KATNIP gene deletion. ResultsWe produced a Katnip null mouse model using CRISPR-Cas12a (Cpf1). The null heterozygotes appeared normal while the homozygotes died around postnatal day 9, showing severe hydrocephalus and deficiency in neuroprogenitor cell proliferation. Katnip-deficient cells in the brain have a higher rate of cilia formation and longer cilia than wild type cells. ConclusionKATNIP loss of function gives rise to hydrocephalus found in Joubert syndrome. The results indicate that KATNIP restricts ciliogenesis and cilia extension and supports proliferation of neuroprogenitor cells in the brain.

cell biology↗

bioRxiv2024

Monoclonal antibodies targeting the FimH adhesin protect against uropathogenic E. coli UTI

As antimicrobial resistance increases, urinary tract infections (UTIs) are expected to pose an increased burden in morbidity and expense on the healthcare system, increasing the need for alternative antibiotic-sparing treatments. Most UTIs are caused by uropathogenic Escherichia coli (UPEC), while Klebsiella pneumoniae causes a significant portion of non-UPEC UTIs. Both bacteria express type 1 pili tipped with the mannose-binding FimH adhesin critical for UTI pathogenesis. We generated and biochemically characterized 33 murine monoclonal antibodies (mAbs) to FimH. Two mAbs protected mice from E. coli UTI. Mechanistically, we show that this protection is Fc-independent and mediated by the ability of these mAbs to sterically block FimH function. Our data reveals that FimH mAbs hold promise as an antibiotic-sparing treatment strategy.

microbiology↗

bioRxiv2024

mRNA-based influenza vaccine expands breadth of B cell response in humans

Summary paragraphEliciting broad and durable antibody responses against rapidly evolving pathogens like influenza viruses remains a formidable challenge1,2. The germinal center (GC) reaction enables the immune system to generate broad, high-affinity, and durable antibody responses to vaccination3-5. mRNA-based severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines induce persistent GC B cell responses in humans6-9. Whether an mRNA-based influenza vaccine could induce a superior GC response in humans compared to the conventional inactivated influenza virus vaccine remains unclear. We assessed B cell responses in peripheral blood and draining lymph nodes in cohorts receiving the inactivated or mRNA-based quadrivalent seasonal influenza vaccine. Participants receiving the mRNA-based vaccine produced more robust plasmablast responses and higher antibody titers to H1N1 and H3N2 influenza A viruses and comparable antibody titers against influenza B virus strains. Importantly, mRNA-based vaccination stimulated robust recall B cell responses characterized by sustained GC reactions that lasted at least 26 weeks post-vaccination in three of six participants analyzed. In addition to promoting the maturation of responding B cell clones, these sustained GC reactions resulted in enhanced engagement of low-frequency pre-existing memory B cells, expanding the landscape of vaccine-elicited B cell clones. This translated to expansion of the serological repertoire and increased breadth of serum antibody responses. These findings reveal an important role for the induction of persistent GC responses to influenza vaccination in humans to broaden the repertoire of vaccine-induced antibodies.

immunology↗

bioRxiv2024

An epilepsy-associated CILK1 variant compromises KATNIP regulation and impairs primary cilia and Hedgehog signaling

Mutations in human CILK1 (ciliogenesis associated kinase 1) are linked to ciliopathies and epilepsy. Homozygous point and nonsense mutations that extinguish kinase activity impair primary cilia function, whereas mutations outside the kinase domain are not well understood. Here, we produced a knock-in mouse equivalent of the human CILK1 A615T variant identified in juvenile myoclonic epilepsy (JME). This residue is in the C-terminal region of CILK1 separate from the kinase domain. Mouse embryo fibroblasts (MEF) with either heterozygous or homozygous A612T mutant alleles exhibited a higher ciliation rate, shorter individual cilia and up-regulation of ciliary Hedgehog signaling. Thus, a single A612T mutant allele was sufficient to impair primary cilia and ciliary signaling in MEFs. Gene expression profiles of wild type versus mutant MEFs revealed profound changes in cilia-related molecular functions and biological processes. CILK1 A615T mutant protein was not increased to the same level as the wild type protein when co-expressed with scaffold protein KATNIP (katanin-interacting protein). Our data show that KATNIP regulation of a JME-associated single residue variant of CILK1 is compromised and this impairs the maintenance of primary cilia and Hedgehog signaling.

cell biology↗

bioRxiv2023

Spatiotemporal development of the human T follicular helper cell response to Influenza vaccination

We profiled blood and draining lymph node (LN) samples from human volunteers after influenza vaccination over two years to define evolution in the T follicular helper cell (TFH) response. We show LN TFH cells expanded in a clonal-manner during the first two weeks after vaccination and persisted within the LN for up to six months. LN and circulating TFH (cTFH) clonotypes overlapped but had distinct kinetics. LN TFH cell phenotypes were heterogeneous and mutable, first differentiating into pre-TFH during the month after vaccination before maturing into GC and IL-10+ TFH cells. TFH expansion, upregulation of glucose metabolism, and redifferentiation into GC TFH cells occurred with faster kinetics after re-vaccination in the second year. We identified several influenza-specific TFH clonal lineages, including multiple responses targeting internal influenza proteins, and show each TFH state is attainable within a lineage. This study demonstrates that human TFH cells form a durable and dynamic multi-tissue network.

immunology↗

bioRxiv2022

SARS-CoV-2 Omicron boosting induces de novo B cell response in humans

The primary two-dose SARS-CoV-2 mRNA vaccine series are strongly immunogenic in humans, but the emergence of highly infectious variants necessitated additional doses of these vaccines and the development of new variant-derived ones1-4. SARS-CoV-2 booster immunizations in humans primarily recruit pre-existing memory B cells (MBCs)5-9. It remains unclear, however, whether the additional doses induce germinal centre (GC) reactions where reengaged B cells can further mature and whether variant-derived vaccines can elicit responses to novel epitopes specific to such variants. Here, we show that boosting with the original SARS- CoV-2 spike vaccine (mRNA-1273) or a B.1.351/B.1.617.2 (Beta/Delta) bivalent vaccine (mRNA-1273.213) induces robust spike-specific GC B cell responses in humans. The GC response persisted for at least eight weeks, leading to significantly more mutated antigen-specific MBC and bone marrow plasma cell compartments. Interrogation of MBC-derived spike-binding monoclonal antibodies (mAbs) isolated from individuals boosted with either mRNA-1273, mRNA-1273.213, or a monovalent Omicron BA.1-based vaccine (mRNA-1273.529) revealed a striking imprinting effect by the primary vaccination series, with all mAbs (n=769) recognizing the original SARS-CoV-2 spike protein. Nonetheless, using a more targeted approach, we isolated mAbs that recognized the spike protein of the SARS-CoV-2 Omicron (BA.1) but not the original SARS-CoV-2 spike from the mRNA-1273.529 boosted individuals. The latter mAbs were less mutated and recognized novel epitopes within the spike protein, suggesting a naive B cell origin. Thus, SARS-CoV-2 boosting in humans induce robust GC B cell responses, and immunization with an antigenically distant spike can overcome the antigenic imprinting by the primary vaccination series.

immunology↗

bioRxiv2021

Germinal centre-driven maturation of B cell response to SARS-CoV-2 vaccination

Germinal centres (GC) are lymphoid structures where vaccine-responding B cells acquire affinity-enhancing somatic hypermutations (SHM), with surviving clones differentiating into memory B cells (MBCs) and long-lived bone marrow plasma cells (BMPCs)1-4. Induction of the latter is a hallmark of durable immunity after vaccination5. SARS-CoV-2 mRNA vaccination induces a robust GC response in humans6-8, but the maturation dynamics of GC B cells and propagation of their progeny throughout the B cell diaspora have not been elucidated. Here we show that anti-SARS-CoV-2 spike (S)-binding GC B cells were detectable in draining lymph nodes for at least six months in 10 out of 15 individuals who had received two doses of BNT162b2, a SARS-CoV-2 mRNA vaccine. Six months after vaccination, circulating S-binding MBCs were detected in all participants (n=42) and S-specific IgG-secreting BMPCs were detected in 9 out of 11 participants. Using a combined approach of single-cell RNA sequencing of responding blood and lymph node B cells from eight participants and expression of the corresponding monoclonal antibodies, we tracked the evolution of 1540 S-specific B cell clones. SHM accumulated along the B cell differentiation trajectory, with early blood plasmablasts showing the lowest frequencies, followed by MBCs and lymph node plasma cells whose SHM largely overlapped with GC B cells. By three months after vaccination, the frequency of SHM within GC B cells had doubled. Strikingly, S+ BMPCs detected six months after vaccination accumulated the highest level of SHM, corresponding with significantly enhanced anti-S polyclonal antibody avidity in blood at that time point. This study documents the induction of affinity-matured BMPCs after two doses of SARS-CoV-2 mRNA vaccination in humans, providing a foundation for the sustained high efficacy observed with these vaccines.

immunology↗

bioRxiv2021

SARS-CoV-2 mRNA vaccination elicits robust and persistent T follicular helper cell response in humans

SARS-CoV-2 mRNA vaccines induce robust anti-spike (S) antibody and CD4+ T cell responses. It is not yet clear whether vaccine-induced follicular helper CD4+ T (TFH) cell responses contribute to this outstanding immunogenicity. Using fine needle aspiration of draining axillary lymph nodes from individuals who received the BNT162b2 mRNA vaccine, we show that frequency of TFH correlates with that of S-binding germinal center B cells. Mining of the responding TFH T cell receptor repertoire revealed a strikingly immunodominant HLADPB1* 04-restricted response to S167-180 in individuals with this allele, which is among the most common HLA alleles in humans. Paired blood and lymph node specimens show that while circulating S-specific TFH cells peak one week after the second immunization, S-specific TFH persist at nearly constant frequencies for at least six months. Collectively, our results underscore the key role that robust TFH cell responses play in establishing long-term immunity by this efficacious human vaccine.

immunology↗

bioRxiv2021

A public vaccine-induced human antibody protects against SARS-CoV-2 and emerging variants

The emergence of antigenically distinct severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants with increased transmissibility is a public health threat. Some of these variants show substantial resistance to neutralization by SARS-CoV-2 infection- or vaccination-induced antibodies, which principally target the receptor binding domain (RBD) on the virus spike glycoprotein. Here, we describe 2C08, a SARS-CoV-2 mRNA vaccine-induced germinal center B cell-derived human monoclonal antibody that binds to the receptor binding motif within the RBD. 2C08 broadly neutralizes SARS-CoV-2 variants with remarkable potency and reduces lung inflammation, viral load, and morbidity in hamsters challenged with either an ancestral SARS-CoV-2 strain or a recent variant of concern. Clonal analysis identified 2C08-like public clonotypes among B cell clones responding to SARS-CoV-2 infection or vaccination in at least 20 out of 78 individuals. Thus, 2C08-like antibodies can be readily induced by SARS-CoV-2 vaccines and mitigate resistance by circulating variants of concern. One Sentence SummaryProtection against SARS-CoV-2 variants by a potently neutralizing vaccine-induced human monoclonal antibody.

immunology↗

bioRxiv2021

Human B cell lineages engaged by germinal centers following influenza vaccination are measurably evolving

Poor efficacy of seasonal influenza virus vaccines is often attributed to pre-existing immunity interfering with the persistence and maturation of vaccine-induced B cell responses.1 Consistent with this notion, no significant increase in somatic hypermutation (SHM) among circulating influenza-binding lineages was detected following seasonal vaccination in humans.2 A more recent study showed that at least a subset of vaccine-induced B cell lineages are recruited into germinal centers (GCs) following vaccination, suggesting that affinity maturation of these lineages can occur.3 Crucially, however, it has not been demonstrated whether these GC-engaged lineages actually accumulate additional SHM. Here, we address this point using a phylogenetic test of measurable evolution. We first validate this test through simulations and demonstrate measurable B cell evolution in known examples of affinity maturation such as the response to HIV infection. We then show that lineages in the blood are rarely measurably evolving following influenza vaccination, but that GC-engaged lineages - likely derived from memory B cells - are frequently measurably evolving. These findings confirm that seasonal influenza virus vaccination can stimulate additional SHM among responding B cell lineages.

immunology↗

bioRxiv2018

B cells transiently exposed to antigen that return to quiescence respond to protein immunization similarly to naive B cells

Transient exposure of B cells to moderately multivalent antigens has been shown to lead to their activation and recruitment into T-dependent B cell response in the presence of T cell help. However, when T cell help is delayed, transiently activated B cells return to a naive-like state. While B cells that briefly encountered cognate antigen and then underwent inactivation are not tolerant, whether they may be hypo-or hyper-responsive to cognate antigen is not known. In this study we show that naive B cells and those previously exposed to antigen and then inactivated generate comparable germinal center and plasma cell responses after immunization with a wide range of antigen concentrations.

immunology↗

bioRxiv2018

B cell receptor crosslinking can augment T cell help-mediated germinal center B cell selection.

Selection of germinal center (GC) B cells with B cell receptors (BCR) possessing high affinity to foreign antigen (Ag) and their differentiation into antibody-secreting long-lived plasma cells is critical for potent long-term humoral immunity. Ag-dependent engagement of GC B cell BCR triggers Ag internalization and loading of antigenic peptides on MHCII molecules for presentation to follicular helper T cells (Tfh) and acquisition of T cell help. However, whether it also provides signals that are critical or synergistic with T cell help for GC B cell selection and differentiation in vivo is not known. Here we show that T cell help is sufficient to induce GC B cell expansion and plasmablast (PB) formation in the absence of recurrent BCR engagement with Ag. Ag-mediated BCR crosslinking on the other hand is not sufficient to promote GC B cell selection, but can synergize with T cell help to enhance the GC B cell and PB responses when T cell help is limiting.

immunology↗

bioRxiv2018

CCL3 promotes germinal center B cells sampling by follicular regulatory T cells and ensures optimal humoral response

Previous studies and our findings suggest upregulated expression of proinflammatory chemokines CCL3/4 in germinal center (GC) centrocytes. However, the role of CCL3/4 for centrocyte interactions with follicular T cells and regulation of humoral immunity is poorly understood. We found that CCL3 promotes chemotaxis of Tfr cells ex vivo. In vivo CCL3 is not required for Tfr cells recruitment of into the GC light zone. However, B cells-intrinsic production of CCL3 promotes their direct interactions and negative regulation by follicular regulatory T cells (Tfr) within GCs.

immunology↗