Biology subjects

Huang, J.

Publications and source records attributed to Huang, J..

At least 487 records · Page 27Linked to original sources

bioRxiv2021

Lung Epithelial Cells Can Produce Antibodies Participating In Adaptive Humoral Immune Responses

It is generally believed that the main source of antibodies is B lymphocytes. In this study, our results first revealed that B cell-deficient mice could not produce antibodies specific for TI-Ags; however, mice with B cell deficiency could produce TD-Ag-specific antibodies, although antibody production was delayed compared with that in BALB/c mice after primary TD-Ag challenge. Subsequently, we identified that mouse lung epithelial cells could produce and secrete Ig, including IgM, IgA or IgG, which could display TD-Ag-specific antibody activity. Notably, the production of TD-Ag-specific antibodies by lung epithelial cells was found to be dependent on CD4+ T cells but not CD8+ T cells. Our findings indicate for the first time that B cells are not the only source of TD-Ag-specific antibodies but are essential for rapid TD-Ag-specific antibody production by non-B cells. This discovery may reveal a new mechanism for the production of specific antibodies.

immunology↗

bioRxiv2021

High-precision mapping of nuclear pore-chromatin interactions reveals new principles of genome organization at the nuclear envelope

The role of nuclear pore complexes (NPCs) in genome organization remains poorly characterized due to technical limitations in probing genome-wide protein-DNA interactions specific to the nuclear periphery. Here, we developed a new sensitive method, NPC-DamID, which combines in vitro reconstitution of nuclear import and DamID technology. The fixation-free method identifies chromatin interactions at the NPCs in intact nuclei from cells and tissues. We found that NPCs are preferentially associated with common and hierarchically arranged super-enhancers (SEs) across multiple cell types. We also uncovered phase-separated condensates at NPCs that compartmentalize and concentrate transcriptional coactivators and structural proteins at SE-regulated genes. Our results support NPCs as anchoring sites for SE regulatory hubs and cell-type-specific transcriptional control.

molecular biology↗

bioRxiv2021

In situ electro-sequencing in three-dimensional tissues

Pairwise mapping of single-cell gene expression and electrophysiology in intact three-dimensional (3D) tissues is crucial for studying electrogenic organs (e.g., brain and heart)1-5. Here, we introduce in situ electro-sequencing (electro-seq), combining soft bioelectronics with in situ RNA sequencing to stably map millisecond-timescale cellular electrophysiology and simultaneously profile a large number of genes at single-cell level across 3D tissues. We applied in situ electro-seq to 3D human induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM) patches, precisely registering the CM gene expression with electrophysiology at single-cell level, enabling multimodal in situ analysis. Such multimodal data integration substantially improved the dissection of cell types and the reconstruction of developmental trajectory from spatially heterogeneous tissues. Using machine learning (ML)-based cross-modal analysis, in situ electro-seq identified the gene-to-electrophysiology relationship over the time course of cardiac maturation. Further leveraging such a relationship to train a coupled autoencoder, we demonstrated the prediction of single-cell gene expression profile evolution using long-term electrical measurement from the same cardiac patch or 3D millimeter-scale cardiac organoids. As exemplified by cardiac tissue maturation, in situ electro-seq will be broadly applicable to create spatiotemporal multimodal maps and predictive models in electrogenic organs, allowing discovery of cell types and gene programs responsible for electrophysiological function and dysfunction.

genomics↗

bioRxiv2021

The Magnaporthe oryzae MAP kinase Pmk1 regulates polycomb repressive complex 2 to reprogram genes expression for biotrophic growth

Biotrophic and hemibiotrophic fungi have evolved the ability to colonize living plant cells, but how they establish biotrophic growth by remodeling gene expression is poorly understood. By using in planta invasive hyphae (IH) of Magnaporthe oryzae to perform an integrated Chromatin immunoprecipitation sequencing (ChIPseq) and RNA-seq analysis, combining with biological and cellular analyses, we found Polycomb repressive complex 2 (PRC2)-mediated epigenetic repression plays a key role in regulating biotrophic growth. ChIPseq for biotrophic IH samples identified 1701 PRC2 target genes. RNA-seq analysis showed that expression of 462 PRC2 target genes were up-regulated in the {Delta}suz12 mutant, while 82 were down-regulated, indicating a major role of PRC2 in gene repression of IH. During biotrophic growth, PRC2 repressed fungal cell wall synthesis genes and extracellular enzyme genes required for penetration, and secondary metabolites biosynthesis genes required for necrotrophic growth. A great number of effector-encoding genes were repressed by PRC2, which were highly expressed during penetration stage, suggesting PRC2 coordinates biotrophic growth by regulating effector suppression for immune evasion. This regulation was finely coordinated by Pmk1, through regulating phosphorylation, nuclear localization and protein abundance of Suz12. Our results indicate that the Pmk1-PRC2 regulatory module is required for gene remodeling to facilitate biotrophic growth in M. oryzae. IMPORTANCEBiotrophic and hemibiotrophic fungi establish a biotrophic stage for infection in host cells. For example, M. oryzae forms appressoria to penetrate host cell and establish a biotrophic growth stage for infection. How gene expression patterns are elaborately controlled for fungal biotrophic growth is largely unknown. In this study, we found that, the PRC2-mediated H3K27me3 repressed fungal penetration-required cell wall synthesis genes and extracellular enzyme genes, and necrotrophic growth-required secondary metabolites biosynthesis genes for biotrophic growth. Interestingly, a great number of effector-encoding genes were also repressed by PRC2 at biotrophic stage, which were highly expressed at penetration stage, suggesting PRC2 coordinates biotrophic growth by regulating effector suppression for immune evasion. The PRC2-mediated epigenetic repression is therefore required for the gene expression remodeling during fungal infection. This regulation was finely coordinated by Pmk1, through regulating nuclear localization and protein abundance of the PRC2 component Suz12.

microbiology↗

bioRxiv2021

Ultrapotent SARS-CoV-2 neutralizing antibodies with protective efficacy against newly emerged mutational variants

Accumulating mutations in the SARS-CoV-2 Spike (S) protein can increase the possibility of immune escape, challenging the present COVID-19 prophylaxis and clinical interventions. Here, 3 receptor binding domain (RBD) specific monoclonal antibodies (mAbs), 58G6, 510A5 and 13G9, with high neutralizing potency blocking authentic SARS-CoV-2 virus displayed remarkable efficacy against authentic B.1.351 virus. Each of these 3 mAbs in combination with one neutralizing Ab recognizing non-competing epitope exhibited synergistic effect against authentic SARS-CoV-2 virus. Surprisingly, structural analysis revealed that 58G6 and 13G9, encoded by the IGHV1-58 and the IGKV3-20 germline genes, both recognized the steric region S470-495 on the RBD, overlapping the E484K mutation presented in B.1.351. Also, 58G6 directly bound to another region S450-458 in the RBD. Significantly, 58G6 and 510A5 both demonstrated prophylactic efficacy against authentic SARS-CoV-2 and B.1.351 viruses in the transgenic mice expressing human ACE2 (hACE2), protecting weight loss and reducing virus loads. These 2 ultrapotent neutralizing Abs can be promising candidates to fulfill the urgent needs for the prolonged COVID-19 pandemic.

immunology↗

bioRxiv2021

Phase Resolution of Heterozygous Sites in Diploid Genomes is Important to Phylogenomic Analysis under the Multispecies Coalescent Model

AO_SCPLOWBSTRACTC_SCPLOWGenome sequencing projects routinely generate haploid consensus sequences from diploid genomes, which are effectively chimeric sequences with the phase at heterozygous sites resolved at random. The impact of phasing errors on phylogenomic analyses under the multispecies coalescent (MSC) model is largely unknown. Here we conduct a computer simulation to evaluate the performance of four phase-resolution strategies (the true phase resolution, the diploid analytical integration algorithm which averages over all phase resolutions, computational phase resolution using the program PHASE, and random resolution) on estimation of the species tree and evolutionary parameters in analysis of multi-locus genomic data under the MSC model. We found that species tree estimation is robust to phasing errors when species divergences were much older than average coalescent times but may be affected by phasing errors when the species tree is shallow. Estimation of parameters under the MSC model with and without introgression is affected by phasing errors. In particular, random phase resolution causes serious overestimation of population sizes for modern species and biased estimation of cross-species introgression probability. In general the impact of phasing errors is greater when the mutation rate is higher, the data include more samples per species, and the species tree is shallower with recent divergences. Use of phased sequences inferred by the PHASE program produced small biases in parameter estimates. We analyze two real datasets, one of East Asian brown frogs and another of Rocky Mountains chipmunks, to demonstrate that heterozygote phase-resolution strategies have similar impacts on practical data analyses. We suggest that genome sequencing projects should produce unphased diploid genotype sequences if fully phased data are too challenging to generate, and avoid haploid consensus sequences, which have heterozygous sites phased at random. In case the analytical integration algorithm is computationally unfeasible, computational phasing prior to population genomic analyses is an acceptable alternative.

evolutionary biology↗

bioRxiv2021

Cytostatic hypothermia and its impact on glioblastoma and survival

Novel therapeutic approaches are needed for patients with glioblastoma (GBM) who otherwise have limited options. Here we studied and deployed non-freezing cytostatic hypothermia to stunt GBM growth. This contrasts with ablative, cryogenic hypothermia: a double-edged sword against tumors infiltrating otherwise healthy tissue. We investigated three grades of hypothermia in vitro and identified a cytostatic window of 20-25{degrees}C. For some glioma lines, 18 h/d of cytostatic hypothermia was sufficient to halt division in vitro. Cytostatic hypothermia induced cell cycle arrest, reduced metabolite production and consumption, and reduced inflammatory cytokine synthesis. Next, we fabricated an experimental device to test local cytostatic hypothermia in vivo in two rodent models of GBM: utilizing the rat F98 and the human U-87 MG lines. Hypothermia more than doubled the median survival of F98 bearing rats from 3.9 weeks to 9.7 weeks and two rats survived through 12 weeks. All U-87 MG bearing rats that successfully received cytostatic hypothermia survived their study period. Thus, this approach lengthened survival without chemical interventions. Unlike targeted therapeutics that are successful in preclinical models but fail in clinical trials, cytostatic hypothermia affects multiple cellular processes simultaneously. This, alongside reduced cellular division, suggests that opportunities for tumor evolution are reduced and the likelihood of translation to larger species may be more likely. In addition, based on our work, designs, and the literature, engineering a patient-centric device is tangible. Taken together, cytostatic hypothermia could be a novel approach to cancer therapy and eventually serve a valuable role to patients with GBM. One Sentence SummaryHypothermia influences multiple cellular pathways, can be a safe and effective approach to halt glioblastoma growth, and holds translational promise.

bioengineering↗

bioRxiv2021

Anti-GD2 antibody disrupts GD2:Siglec-7 interactions and synergizes with CD47 blockade to mediate tumor eradication

The disialoganglioside GD2 is consistently overexpressed in neuroblastoma and osteosarcoma, and is variably expressed in other sarcomas, gliomas, neuroendocrine tumors, and epithelial cancers. Anti-GD2 antibodies have improved the survival rates of patients with neuroblastoma only when administered as part of intense chemotherapy-based cytotoxic regimens, which are associated with debilitating late effects including hearing loss, growth retardation, and secondary leukemias. Despite broad expression of GD2 on osteosarcoma, anti-GD2 antibody has not mediated significant antitumor activity in that disease or any other GD2+ cancers. CD47 is a checkpoint molecule overexpressed on tumor cells that inhibits macrophage activity, and CD47 blockade has demonstrated promising clinical activity in early human trials. We investigated whether anti-CD47 antibody could enhance the efficacy of anti-GD2 antibody in neuroblastoma and other GD2+ malignancies. We demonstrate substantial synergy of these two agents, resulting in the recruitment of tumor associated macrophages (TAMs) to mediate robust and durable anti-tumor responses. The responses are driven by GD2-specific factors that reorient the balance of macrophage activity towards phagocytosis of tumor cells, including disruption of a newly described GD2:Siglec-7 axis. These results demonstrate the unique synergy of combining anti-GD2 with anti-CD47, which has the potential to significantly enhance outcomes for children with neuroblastoma and osteosarcoma and will soon be investigated in a first-in-human clinical trial.

immunology↗

bioRxiv2021

Myosin turnover controls actomyosin contractile instability

Actomyosin contractile force is harnessed for diverse functions, from cell division to morphogenesis during development. However, actomyosin contractility is intrinsically unstable to self-reinforcing spatial variations that destroy actomyosin architecture if unopposed. The full instability was rarely observed, and how cells control the instability is not established. Here, we observed the instability run its full course in isolated cytokinetic contractile rings lacking component turnover. Myosin II aggregated hierarchically into aggregates of growing size and separation up to a maximum. Molecularly explicit simulations reproduced hierarchical aggregation that precipitated tension loss and ring fracture, and identified the maximum separation as the length of actin filaments mediating mechanical communication between aggregates. Late stage simulated aggregates had aster-like morphology with polarity sorted actin, similar to late stage actomyosin systems in vitro. Our results suggest myosin II turnover controls actomyosin contractile instability in normal cells, setting myosin aggregate size and intercepting catastrophic hierarchical aggregation and fracture.

cell biology↗

bioRxiv2021

Genome assembly of the maize inbred line A188 provides a new reference genome for functional genomics

Heretofore, little is known about the mechanism underlying the genotype-dependence of embryonic callus (EC) induction, which has severely inhibited the development of maize genetic engineering. Here, we report the genome sequence and annotation of a maize inbred line with high EC induction ratio, A188, which is assembled from single-molecule sequencing and optical genome mapping. We assembled a 2,210 Mb genome with a scaffold N50 size of 11.61 million bases (Mb), compared to those of 9.73 Mb for B73 and 10.2 Mb for Mo17. Comparative analysis revealed that [~]30% of the predicted A188 genes had large structural variations to B73, Mo17 and W22 genomes, which caused considerable protein divergence and might lead to phenotypic variations between the four inbred lines. Combining our new A188 genome, previously reported QTLs and RNA sequencing data, we reveal 8 large structural variation genes and 4 differentially expressed genes playing potential roles in EC induction. HighlightOur manuscript presents a high-quality reference genome of the inbred line A188, and provides new insights into candidate genes underlying maize embryonic callus induction and other maize agronomic traits.

genetics↗

bioRxiv2021

Loss of SETD1B results in the redistribution of genomic H3K4me3 in the oocyte

Histone 3 lysine 4 trimethylation (H3K4me3) is an epigenetic mark found at gene promoters and CpG islands. H3K4me3 is essential for mammalian development, yet mechanisms underlying its genomic targeting are poorly understood. H3K4me3 methyltransferases SETD1B and MLL2 are essential for oogenesis. We investigated changes in H3K4me3 in Setd1b conditional knockout (cKO) oocytes using ultra-low input ChIP-seq, with comparisons to DNA methylation and gene expression analyses. H3K4me3 was redistributed in Setd1b cKO oocytes showing losses at active gene promoters associated with downregulated gene expression. Remarkably, many regions also gained H3K4me3, in particular those that were DNA hypomethylated, transcriptionally inactive and CpG-rich, which are hallmarks of MLL2 targets. Consequently, loss of SETD1B disrupts the balance between MLL2 and de novo DNA methyltransferases in determining the epigenetic landscape during oogenesis. Our work reveals two distinct, complementary mechanisms of genomic targeting of H3K4me3 in oogenesis, with SETD1B linked to gene expression and MLL2 to CpG content. Graphical AbstractIn oogenesis, SETD1B and CXXC1 target H3K4me3 to actively transcribed gene promoters, while MLL2 targets transcriptionally inactive regions based on underlying CpG composition (upper panel). When SETD1B is ablated, H3K4me3 is lost at a subset of active promoters, resulting in downregulation of transcription (lower panel). Loss of SETD1B alters the activity of MLL2, permitting MLL2 to deposit H3K4me3 at CpG-rich regions, many of which should otherwise be DNA methylated. Thus, it is evident that MLL2 and de novo DNMTs compete for genomic occupancy late in oogenesis, and loss of SETD1B disrupts the balance of these mechanisms. O_FIG_DISPLAY_L [Figure 1] M_FIG_DISPLAY C_FIG_DISPLAY

developmental biology↗

bioRxiv2021

SUMOylation of GMFB regulates the stability and function of GMF in RPE cells under oxidative stress and inflammation

Glia maturation factor beta (GMFB) is a growth and differentiation factor that act as an intracellular regulator of signal transduction pathways. The SUMOylation is a post-translational modification (PTM) that plays a key role in protein subcellular localization, stability, transcription, and enzymatic activity. Recent studies have highlighted the importance of SUMOylation in the inflammation and progression of numerous diseases. But little is known about the relationship between GMFB and SUMOylation. Here we first report that GMFB can be mono-SUMOylated at multiple sites by the covalent addition of a single SUMO1 protein, and identified K20, K35, K58, and K97 as major SUMO acceptor sites. We also found that SUMOylation leading to increased stability and trans-localization of GMFB. Furthermore, RNA-seq data and Real-time quantitative polymerase chain reaction (rt-qPCR) also indicated that the SUMOylated GMFB upregulated multiple pathways, including the cytokine-cytokin receptor interaction, NOD-like receptor signaling pathway, TNF signaling pathway, RIG-I-like receptor signaling pathway, and NF-kappa B signaling pathway. Our studies intend to provide a novel direction for the study into the biofunction of GMFB, SUMOylated GMFB and the mechanism, clinical therapy, and prognosis of inflammation-related RPE disorders like age-related macular degeneration (AMD) and diabetic retinopathy (DR).

biochemistry↗

bioRxiv2021

miRNA-dependent poly(A) length control in uncoupling transcription and translation of haploid male germ cells

As one of the post-transcriptional regulatory mechanisms, transcription and translations uncoupling plays an essential role in development and adulthood physiology. However, it remains elusive how thousands of mRNAs get translationally silenced while stability is maintained for up to hours or even days before translation. In addition to oocytes and neurons, developing spermatids have significant uncoupling of transcription and translation for delayed translation. Therefore, spermiogenesis represents an excellent in vivo model for investigating the mechanism underlying uncoupled transcription and translation. Through full-length poly(A) deep sequencing, we discovered dynamic changes in poly(A) length through deadenylation and re-polyadenylation. Deadenylation appeared to be mediated by microRNAs (miRNAs), and transcripts with shorter poly(A) tails tend to be sequestered into ribonucleoproteins (RNPs) for translational repression and stabilization. In contrast, re-polyadenylation allows for translocation of the translationally repressed transcripts from RNPs to polysomes for translation. Overall, our data suggest that miRNA-dependent poly(A) length control represents a novel mechanism underlying uncoupled translation and transcription in haploid male germ cells.

molecular biology↗

bioRxiv2021

MAPK Pathway Inhibition as A Rational Therapeutic Strategy for MiR-138-5p/PAQR3 Dysregulation-mediated Epirubicin Resistance in Triple-negative Breast Cancer

Anthracyclines, such as epirubicin, activate the mitogen-activated protein kinase (MAPK) pathway in breast cancer (BC). Better predictors of tumor response are needed to guide de-intensification of anthracyclines when used in BC treatment. Here, we aimed to see if MAPK activation was responsible and targetable for epirubicin resistance, and to explore mechanisms and predictive markers for resistance. MAPK pathway inhibitors were used to ameliorate epirubicin resistance. Negative regulators of MAPK were screened to identify the essential gene cascades required for activation of the pathway. In vitro and in vivo approaches were applied to investigate epirubicin resistance. The regulatory miRNA was identified through bioinformatics-based screening and luciferase reporter assay. 114 estrogen receptor negative patients who received epirubicin monotherapy were included to evaluate predictive markers for tumor response. The MAPK pathway was activated in cells resistant to epirubicin; MAPK inhibition ameliorated epirubicin resistance. In triple-negative breast cancer (TNBC), progestin and adipoQ receptor 3 (PAQR3) were the most significantly decreased negative MAPK regulators. PAQR3 increased epirubicin sensitivity and suppressed MAPK activation in resistant cells. MiR-138-5p was increased in epirubicin resistant cells, and was shown to downregulate PAQR3, causing resistance in epirubicin resistant cells. PAQR3 was an independent factor in predicting response to epirubicin (OR=4.86, 95%CI=1.13-20.87, P=0.034), and possessed a high negative predictive value (NPV) (0.93; 95%CI=0.83-0.97). In addition, PAQR3 exhibited a better predictive value in patients older than 50 years (12.92 (95% CI, 1.43-116.78, P = 0.023). The combinative use of PAQR3 and topoisomerase II- (TOP2A) led to an increased specificity (0.70; 95%CI=0.61-0.79), when compared with either PAQR3 or TOP2A alone. MAPK inhibition ameliorated epirubicin resistance. MiR-138-5p-induced PAQR3 reduction causes epirubicin resistance in TNBC via activation of MAPK cascades. PAQR3 is an independent and favorable predictor response to epirubicin in BC.

cancer biology↗

bioRxiv2021

B/tMSI-CAST: a systematic approach for microsatellite instability detection in both tumor tissue and plasma specimens from next-generation sequencing data

Microsatellite instability (MSI) is a well-established prognostic and predictive biomarker in certain types of cancers. MSI detection using tumour tissue is often limited by the availability of specimens. Next generation sequencing (NGS)-based MSI detection in plasma cell-free DNA (cfDNA) is challenged by a much lower signal-to-noise ratio. We developed a highly accurate cfDNA MSI detection method called bMSI-CAST (blood MSI Caller Adjusted with Sequence duplicaTes), with improvement on three features including a set of locus selection principles ensuring loci with high robustness and compatibility across sequencing platforms, an MSI-specific duplicate removal strategy, and a calling algorithm that dynamically matches baselines with a broad range of duplication levels. Analytical validation via MSI-high (MSI-H) cell gDNA showed an LOD of 0.15%. Furthermore, in an analysis of 95 evaluable cfDNA samples from patients with gastrointestinal cancers, bMSI-CAST exhibited a positive predictive agreement (PPA) of 92.9% (39/42) and negative predictive agreement (NPA) of 100% (53/53) with tissue MSI-PCR. In conclusion, bMSI-CAST provides novel and advanced solutions to key aspects fundamental to cfDNA MSI calling but not sufficiently addressed by existing methods, and it is a validated method ready to be applied to aid clinical decisions for cancer patients.

bioinformatics↗

bioRxiv2021

ClusterMap: multi-scale clustering analysis of spatial gene expression

Quantifying RNAs in their spatial context is crucial to understanding gene expression and regulation in complex tissues. In situ transcriptomic methods generate spatially resolved RNA profiles in intact tissues. However, there is a lack of a unified computational framework for integrative analysis of in situ transcriptomic data. Here, we present an unsupervised and annotation-free framework, termed ClusterMap, which incorporates physical proximity and gene identity of RNAs, formulates the task as a point pattern analysis problem, and thus defines biologically meaningful structures and groups. Specifically, ClusterMap precisely clusters RNAs into subcellular structures, cell bodies, and tissue regions in both two- and three-dimensional space, and consistently performs on diverse tissue types, including mouse brain, placenta, gut, and human cardiac organoids. We demonstrate ClusterMap to be broadly applicable to various in situ transcriptomic measurements to uncover gene expression patterns, cell-cell interactions, and tissue organization principles from high-dimensional transcriptomic images.

genomics↗

bioRxiv2021

Talaromyces marneffei promotes M2 polarization of human macrophages by downregulating SOCS3 expression and activating TLR9 pathway

Little is known about how Talaromyces marneffei, a thermally dimorphic fungus that causes substantial morbidity and mortality in Southeast Asia, evades the human immune system. Polarization of macrophages into fungal-inhibiting M1 and fungal-promoting M2 types has been shown to play an important role in the innate immune response against fungal pathogens. This mechanism has not been defined for T. marneffei. Here, we demonstrated that T. marneffei promotes its survival in human macrophages by inducing them towards M2 polarization. Our investigations of the mechanism revealed that T. marneffei infection led to SOCS3 protein degradation by inducing tyrosine phosphorylation, thereby relieving the inhibitory effect of SOCS3 on p-STAT6, a key factor for M2 polarization. Our SOCS3-overexpression experiments showed that SOCS3 is a positive regulator of M1 polarization and plays an important role in limiting M2 polarization. Furthermore, we found that inhibition of TLR9 pathway partially blocked T. marneffei-induced M2 polarization and significantly enhanced the killing activity of macrophages against T. marneffei. Collectively, these results reveal a novel mechanism by which T. marneffei evades the immune response of human macrophages.

microbiology↗

bioRxiv2021

Broadly reactive human monoclonal antibodies targeting the pneumococcal histidine triad protein protect against fatal pneumococcal infection

Streptococcus pneumoniae remains a leading cause of bacterial pneumonia despite the widespread use of vaccines. While vaccines are effective at reducing the incidence of most vaccine-included serotypes, a rise in infection due to non-vaccine serotypes, and moderate efficacy against some vaccine included serotypes have contributed to high disease incidence. Additionally, numerous isolates of S. pneumoniae are antibiotic or multi-drug resistant. Several conserved pneumococcal proteins prevalent in the majority of serotypes have been examined as vaccines in preclinical and clinical trials. An additional, yet unexplored tool for disease prevention and treatment is the use of human monoclonal antibodies (mAbs) targeting conserved pneumococcal proteins. Here, we isolate the first human mAbs (PhtD3, PhtD6, PhtD7, PhtD8, PspA16) against the pneumococcal histidine triad protein (PhtD), and the pneumococcal surface protein A (PspA), two conserved and protective antigens. mAbs to PhtD target diverse epitopes on PhtD, and mAb PspA16 targets the N-terminal segment of PspA. The PhtD-specific mAbs bind to multiple serotypes, while mAb PspA16 serotype breadth is limited. mAbs PhtD3 and PhtD8 prolong the survival of mice infected with pneumococcal serotype 3. Furthermore, mAb PhtD3 prolongs the survival of mice in intranasal and intravenous infection models with pneumococcal serotype 4, and in mice infected with pneumococcal serotype 3 when administered 24 hours after pneumococcal infection. All PhtD and PspA mAbs demonstrate opsonophagocytic activity, suggesting a potential mechanism of protection. Our results provide new human mAbs for pneumococcal disease prevention and treatment, and identify epitopes on PhtD and PspA recognized by human B cells.

immunology↗