Biology subjects

Ross, T.

Publications and source records attributed to Ross, T..

At least 19 recordsLinked to original sources

bioRxiv2026

Sonic Hedgehog Is An Important Regulator Of Intervertebral Disc Homeostasis And Rejuvenation

Intervertebral disc degeneration and associated neurological symptoms constitute a global health burden, yet no cure is currently available (1,2). Each disc consists of a central nucleus pulposus, surrounded by annulus fibrosus, and end plates connecting it to the growth plates of adjacent vertebral bodies. The notochord-descendant nucleus pulposus continues to express sonic hedgehog, which regulates the proliferation and differentiation of all components of neonatal mouse discs (3-7). Sonic hedgehog expression and function decline with age and are associated with disc pathologies, including terminal differentiation of nucleus pulposus cells to chondrocyte-like phenotype (7,8). Here, we used fate-mapping and conditional genetic mouse models to test the role of sonic hedgehog in the homeostasis of aging discs. We found that loss of NP-derived Shh is sufficient to accelerate multiple features of age-associated disc degeneration, including reduced NP cell number, altered matrix turnover, and induction of inflammatory, angiogenic and neurotrophic programs. Age-related disc pathologies were more prevalent in the lumbosacral discs of mice, like in humans (8-13). Also, like mice, the expression of sonic hedgehog and its targets by human nucleus pulposus cells declines with age and pathological degeneration. Moreover, pharmacologic Hedgehog activation partially restored anabolic gene expression and reduced catabolic, inflammatory and neurotrophic mediators in degenerated human NP explants ex vivo. These findings indicate that Sonic hedgehog, a developmental signal retained in the adult NP, is functionally active and required for disc homeostasis during aging and supports activation of hedgehog signaling as a candidate disease-modifying pathway for intervertebral disc pathologies.

developmental biology↗

bioRxiv2024

Shared and distinct adaptations to early-life exercise training based on inborn fitness

BackgroundLow cardiorespiratory fitness due to genetics increases the risk for cardiometabolic disease. Endurance exercise training promotes cardiorespiratory fitness and improves cardiometabolic risk factors, but with great heterogeneity. Here, we tested the hypothesis that the metabolic phenotype imparted by low parental (inborn) cardiorespiratory fitness would be overcome by early-life exercise training, and that exercise adaptations would be influenced in part by inborn fitness. MethodsAt 26 days of age, male and female rat low-capacity runners (LCR, n=20) and high-capacity runners (HCR, n=20) generated by artificial selection were assigned to either sedentary control (CTRL, n=10) or voluntary wheel running (VWR, n=10) for 6 weeks. Post-intervention, whole-body metabolic phenotyping was performed, and the respiratory function of isolated skeletal muscle and liver mitochondria assayed. Transcriptomics and proteomics were performed on skeletal muscle and liver tissue using RNA-sequencing and mass spectrometry, respectively. ResultsDaily VWR volume was 1.8-fold higher in HCR-VWR compared to LCR-VWR. In LCR, VWR reduced adiposity and enhanced glucose tolerance, coincident with elevated total energy expenditure. While intrinsic skeletal muscle mitochondrial respiratory function was unaffected by VWR, estimated skeletal muscle oxidative capacity increased in VWR groups owing to greater mitochondrial content. In the liver, both maximal oxidative capacity and ATP-linked respiration were higher in HCR-VWR than HCR-CTRL. Transcriptomic and proteomic profiling revealed extensive remodeling of skeletal muscle and liver tissue by VWR, elements of which were both shared and distinct based on inborn fitness. SummaryEarly-life exercise training partially overcomes the metabolic phenotype imparted by low inborn cardiorespiratory fitness. However, molecular adaptations to VWR are partly influenced by inborn fitness, which may have implications for personalized exercise medicine.

physiology↗

bioRxiv2024

Metabolic interplay drives population cycles in a cross-feeding microbial community

Population cycles are prevalent in ecosystems and play key roles in determining their functions1,2. While multiple mechanisms have been theoretically shown to generate population cycles3-6, there are limited examples of mutualisms driving self-sustained oscillations. Using an engineered microbial community that cross-feeds essential amino acids, we experimentally demonstrate cycles in strain abundance that are robust across environmental conditions. A nonlinear dynamical model that incorporates the experimentally observed cross-inhibition of amino acid production recapitulates the population cycles. The model shows that the cycles represent internally generated relaxation oscillations, which emerge when fast resource dynamics with positive feedback drive slow changes in strain abundance. Our findings highlight the critical role of resource dynamics and feedback in shaping population cycles in microbial communities and have implications for biotechnology.

systems biology↗

bioRxiv2024

Multi-COBRA hemagglutinin formulated with cGAMP microparticles elicit protective immune responses against influenza viruses

Influenza viruses cause a common respiratory disease known as influenza. In humans, seasonal influenza viruses can lead to epidemics, with avian influenza viruses of particular concern because they can infect multiple species and lead to unpredictable and severe disease. Therefore, there is an urgent need for a universal influenza vaccine that provides protection against seasonal and pre-pandemic influenza virus strains. The cyclic GMP-AMP (cGAMP) is a promising adjuvant for subunit vaccines that promotes type I interferons production through the stimulator of interferon genes (STING) pathway. The encapsulation of cGAMP in acetalated dextran (Ace-DEX) microparticles (MPs) enhances its intracellular delivery. In this study, the Computationally Optimized Broadly Reactive Antigen (COBRA) methodology was used to generate H1, H3, and H5 vaccine candidates. Monovalent and multivalent COBRA HA vaccines formulated with cGAMP Ace-DEX MPs were evaluated in a mouse model for antibody responses and protection against viral challenge. Serological analysis showed that cGAMP MPs adjuvanted monovalent and multivalent COBRA vaccines elicited robust antigen-specific antibody responses after a prime-boost vaccination and antibody titers were further enhanced after second boost. Compared to COBRA vaccine groups with no adjuvant or blank MPs, the cGAMP MPs enhanced HAI antibody responses against COBRA vaccination. The HAI antibody titers were not significantly different between cGAMP MPs adjuvanted monovalent and multivalent COBRA vaccine groups for most of the viruses tested in panels. The cGAMP MPs adjuvanted COBRA vaccines groups had higher antigen-specific IgG2a binding titers than the COBRA vaccine groups with no adjuvant or blank MPs. The COBRA vaccines formulated with cGAMP MPs mitigated disease caused by influenza viral challenge and decreased pulmonary viral titers in mice. Therefore, the formulation of COBRA vaccines plus cGAMP MPs is a promising universal influenza vaccine that elicits protective immune responses against human seasonal and pre-pandemic strains.

immunology↗

bioRxiv2024

Pre-existing Immunity to Influenza Aids Ferrets in Developing Stronger and Broader Vaccine-induced Antibody Responses

Influenza seasons occur annually, building immune history for individuals, but the influence of this history on subsequent influenza vaccine protection remains unclear. We extracted data from an animal trial to study its potential impact. The trial involved 80 ferrets, each receiving either one type of infection or a placebo before vaccination. We quantified the vaccine protection by evaluating hemagglutination inhibition (HAI) antibody titer responses. We tested whether hosts with different infection histories exhibited similar level of responses when receiving the same vaccine for all homologous and heterologous outcomes. We observed that different pre-existing immunities were generally beneficial to vaccine induced responses, but varied in magnitude. Without pre-immunity, post-vaccination HAI titers after the 1st dose of the vaccine were less likely to be above 1:40, and a booster shot was needed. Our study suggests that pre-existing immunity may strengthen and extend the homologous and heterologous vaccine protection.

immunology↗

bioRxiv2024

Patient Subtyping Analysis of Baseline Multi-omic Data Reveals Distinct Pre-immune States Predictive of Vaccination Responses

Understanding the molecular mechanisms that underpin diverse vaccination responses is a critical step toward developing efficient vaccines. Molecular subtyping approaches can offer valuable insights into the heterogeneous nature of responses and aid in the design of more effective vaccines. In order to explore the molecular signatures associated with the vaccine response, we analyzed baseline transcriptomics data from paired samples of whole blood, proteomics and glycomics data from serum, and metabolomics data from urine, obtained from influenza vaccine recipients (2019-2020 season) prior to vaccination. After integrating the data using a network-based model, we performed a subtyping analysis. The integration of multiple data modalities from 62 samples resulted in five baseline molecular subtypes with distinct molecular signatures. These baseline subtypes differed in the expression of pre-existing adaptive or innate immunity signatures, which were linked to significant variation across subtypes in baseline immunoglobulin A (IgA) and hemagglutination inhibition (HAI) titer levels. It is worth noting that these significant differences persisted through day 28 post-vaccination, indicating the effect of initial immune state on vaccination response. These findings highlight the significance of interpersonal variation in baseline immune status as a crucial factor in determining vaccine response and efficacy. Ultimately, incorporating molecular profiling could enable personalized vaccine optimization.

immunology↗

bioRxiv2024

Discovery and Characterization of a Pan-betacoronavirus S2-binding antibody

SUMMARY/ABSTRACTThree coronaviruses have spilled over from animal reservoirs into the human population and caused deadly epidemics or pandemics. The continued emergence of coronaviruses highlights the need for pan-coronavirus interventions for effective pandemic preparedness. Here, using LIBRA-seq, we report a panel of 50 coronavirus antibodies isolated from human B cells. Of these antibodies, 54043-5 was shown to bind the S2 subunit of spike proteins from alpha-, beta-, and deltacoronaviruses. A cryo-EM structure of 54043-5 bound to the pre-fusion S2 subunit of the SARS-CoV-2 spike defined an epitope at the apex of S2 that is highly conserved among betacoronaviruses. Although non-neutralizing, 54043-5 induced Fc-dependent antiviral responses, including ADCC and ADCP. In murine SARS-CoV-2 challenge studies, protection against disease was observed after introduction of Leu234Ala, Leu235Ala, and Pro329Gly (LALA-PG) substitutions in the Fc region of 54043-5. Together, these data provide new insights into the protective mechanisms of non-neutralizing antibodies and define a broadly conserved epitope within the S2 subunit.

molecular biology↗

bioRxiv2023

Differential cross-reactivity to the influenza B virus haemagglutinin underpins lineage-specific susceptibility between birth cohorts

Influenza exposures early in life are believed to shape future susceptibility to influenza infections by imprinting immunological biases that engender differential cross-reactivity to future influenza viruses, but direct serological evidence linked to susceptibility is limited. We analysed hemagglutination-inhibition titres in 1451 cross-sectional samples collected between 1992-2020, from individuals born between 1917-2008, against influenza B virus (IBV) isolates from 1940-2021, including future isolates that circulated after sample collection. We demonstrate that immunological biases are conferred by early life IBV infection and result in lineage-specific cross-reactivity of a birth cohort towards future IBV isolates. This translates into differential estimates of susceptibility between birth cohorts towards the two IBV antigenic lineages, explaining lineage-specific age distributions of observed medically attended IBV infections. Our data bridge a critical gap between early life exposure, cross-reactivity, and influenza epidemiology and identify a plausible model to further dissect the interplay between host immunity, viral evolution and epidemiology.

immunology↗

bioRxiv2023

Assessment of contaminants, health and survival of migratory shorebirds in natural versus artificial wetlands - the potential of wastewater treatment plants as alternative habitats

The rapid destruction of natural wetland habitats over past decades has been partially offset by an increase in artificial wetlands. However, these also include wastewater treatment plants, which may pose a pollution risk to the wildlife using them. We studied two long-distance Arctic-breeding migratory shorebird species, curlew sandpiper (Calidris ferruginea, n=70) and red-necked stint (Calidris ruficollis, n=100), while on their Australian non-breeding grounds using a natural wetland versus an artificial wetland at a wastewater treatment plant (WTP). We compared pollutant exposure (elements and per- and poly-fluoroalkyl substances/PFASs), disease (avian influenza), physiological status (oxidative stress) of the birds at the two locations from 2011-2020, and population survival from 1978-2019. Our results indicated no significant differences in blood pellet pollutant concentrations between the habitats except mercury (WTP median: 224 ng/g, range: 19-873 ng/g; natural wetland: 160 ng/g, 22-998 ng/g) and perfluorooctanesulfonic acid (WTP median: 52 ng/g, range: <0.01-1280 ng/g; natural wetland: 14 ng/g, <0.01-379 ng/g) which were higher at the WTP, and selenium which was lower at the WTP (WTP median: 5000 ng/g, range: 1950-34400 ng/g; natural wetland: 19200 ng/g, 4130-65200 ng/g). We also measured higher blood o,o-dityrosine (an indicator of protein damage) at the WTP. No significant differences were found for adult survival, but survival of immature birds at the WTP appeared to be lower which could be due to higher dispersal to other wetlands. Interestingly, we found active avian influenza infections were higher in the natural habitat, while seropositivity was higher in the WTP, seemingly not directly related to pollutant exposure. Overall, we found negligible differences in pollutant exposure, health and survival of the shorebirds in the two habitats. Our findings suggest that appropriately managed wastewater treatment wetlands may provide a suitable alternative habitat to these migratory species, curbing the decline of shorebird populations from widespread habitat loss.

ecology↗

bioRxiv2022

Complex changes in serum protein levels upon recovery from SARS-CoV2 infection

The COVID-19 pandemic, triggered by severe acute respiratory syndrome coronavirus 2, has affected millions of people worldwide. Much research has been dedicated to our understanding of COVID-19 disease heterogeneity and severity, but less is known about recovery associated changes. To address this gap in knowledge, we quantified the proteome from serum samples from 29 COVID-19 convalescents and 29 age-, race-, and sex-matched healthy controls. Samples were acquired within the first months of the pandemic. Many proteins from pathways known to change during acute COVID-19 illness, such as from the complement cascade, coagulation system, inflammation and adaptive immune system, had returned to levels seen in healthy controls. In comparison, we identified 22 and 15 proteins with significantly elevated and lowered levels, respectively, amongst COVID-19 convalescents compared to healthy controls. Some of the changes were similar to those observed for the acute phase of the disease, i.e. elevated levels of proteins from hemolysis, the adaptive immune systems, and inflammation. In contrast, some alterations opposed those in the acute phase, e.g. elevated levels of CETP and APOA1 which function in lipid/cholesterol metabolism, and decreased levels of proteins from the complement cascade (e.g. C1R, C1S, and VWF), the coagulation system (e.g. THBS1 and VWF), and the regulation of the actin cytoskeleton (e.g. PFN1 and CFL1) amongst COVID-19 convalescents. We speculate that some of these shifts might originate from a transient decrease in platelet counts upon recovery from the disease. Finally, we observed race-specific changes, e.g. with respect to immunoglobulins and proteins related to cholesterol metabolism.

immunology↗

bioRxiv2022

Proteomic signatures of the serological response to flu vaccination in a large human cohort study

The serological response to the influenza virus vaccine is highly heterogeneous for reasons that are not entirely clear. While the impact of demographic factors such as age, body mass index (BMI), sex, prior vaccination and titer levels are known to impact seroconversion, they only explain a fraction of the response. To identify signatures of the vaccine response, we quantified 273 proteins from serum samples of 160 flu vaccine recipients (2019-2020 season). We found that levels of proteins functioning in cholesterol transport were positively associated with seroconversion, likely linking to the known impact of BMI. When adjusting seroconversion for the demographic factors, we identified additional, unexpected signatures: proteins regulating actin cytoskeleton dynamics were significantly elevated in participants with high adjusted seroconversion. Viral strain specific analysis showed that this trend was largely driven by the H3N2 strain. Further, we identified complex associations between adjusted seroconversion and other factors: levels of proteins of the complement system associated positively with adjusted seroconversion in younger participants, while they were associated negatively in the older population. We observed the opposite trends for proteins of high density lipoprotein remodeling, transcription, and hemostasis. In sum, careful integrative modeling can extract new signatures of seroconversion from highly variable data that suggest links between the humoral response as well as immune cell communication and migration.

immunology↗

bioRxiv2022

The temporal organization of corticostriatal communications

The cortex and striatum are linked by hundreds of thousands of structural connections, and the transmission of temporally aligned communications across many of these connections at once is an electrophysiological prerequisite for striatal activation. Despite the importance of communication timing in corticostriatal circuitry, there is little understanding of its system-level organization and properties. To investigate this, we leveraged emerging methods to "temporally unwrap" fMRI data and measure patterns of cortex-striatum node-pair coactivation at frame-wise (i.e., <1 sec) resolution in low head-motion subjects from the Human Connectome Project. First, we identify communities of cortex-striatum node-pairs with preferentially synchronized coactivation patterns. Surprisingly, we find that the map of striatal areas with temporally aligned cortical coactivation patterns does not simply reflect the map of striatal areas with similar cortical connectivity profiles. As a result of the distinct spatial organization of these gradients, striatal nodes connected to similar areas of cortex may nonetheless interact with these cortical areas at different times, and striatal nodes connected to different areas of cortex may nonetheless interact with these areas at similar times. We provide evidence for a possible mechanism driving this divergence: striatal nodes with similar cortical connectivity profiles may have differently timed interactions with cortex if they have different modulatory input profiles (i.e., from the midbrain and thalamus) that differentially gate their responsivity to cortical input. Overall, this blended organization may serve to both increase the repertoire of striatal responses to frontal input and facilitate coordination across functional domains in the temporal dimension. Findings provide a framework to investigate the role of corticostriatal temporal coordination in behavior and disease. SIGNIFICANCE STATEMENTWe provide the first systems-level account of temporal communication patterns between cortex-striatum node-pairs, mapping communities of node-pairs with synchronized communication patterns using an emerging fMRI temporal-unwrapping technique and providing evidence for the mechanism that dictates the organization of these communities. Findings have broad implications for our understanding of the functional architecture of corticostriatal circuits.

neuroscience↗

bioRxiv2022

Differential recognition of computationally optimized H3 hemagglutinin influenza vaccine candidates by human antibodies

Among circulating influenza viruses in humans, H3N2 viruses typically evolve faster than other subtypes and have caused severe illness and deaths in millions of people since emerging in 1968. Computationally optimized broadly reactive antigen (COBRA) technology is one strategy to broaden vaccine-elicited antibody responses among influenza subtypes. In this study, we determined the structural integrity of an H3N2 COBRA HA, TJ5, and, as nearly all humans have pre-existing immunity to H3N2 influenza viruses, we probed the antigenic profile of several H3N2 COBRA HAs by assessing recognition of these immunogens by human B cells and monoclonal antibodies (mAbs). Of three recently described COBRA H3 HA antigens (TJ5, NG2, and J4), we determined that TJ5 and J4 HA proteins recognize pre-existing B cells (from the 2017-2018 vaccine season) more effectively than NG2 HA and a wild type Hong Kong/4801/2014 protein. H3 HA-specific human mAbs recognize wild type and COBRA HA proteins, and have functional activity against a broad panel of H3N2 viruses. mAb TJ5-5 recognizes TJ5 and J4 HA proteins, but has poor recognition of NG2 HA, similar to the global B cell analysis. To probe these recognition differences and to verify the structural integrity of the TJ5 HA protein, we determined a 3.4 [A] structure via cryo-electron microscopy of TJ5-5 complexed with the TJ5 HA, which revealed residues important to the differential binding. Overall, these studies determined that COBRA H3 HA proteins have correct antigenic and structural features, and are recognized by B cells and mAbs isolated from seasonally vaccinated humans. ImportanceVaccine development for circulating influenza viruses, particularly for the H3N2 subtype, remains challenging due to consistent antigenic drift. Computationally optimized broadly reactive antigen (COBRA) technology has proven effective for broadening influenza hemagglutinin (HA) elicited antibody responses compared to wild type immunogens. Here we determined the structural features and antigenic profiles of H3 COBRA HA proteins. Two H3 COBRA HA proteins, TJ5 and J4, are better recognized by pre-existing B cells and monoclonal antibodies from the 2017-2018 vaccine season compared to COBRA NG2 and a wild type A/Hong Kong/2014 HA protein. We determined a cryo-EM structure of one mAb that poorly recognizes NG2, mAb TJ5-5, in complex with the TJ5 COBRA HA protein and identified residues critical to mAb recognition. As NG2 is more effective than TJ5 for a recent Hong Kong/2019 virus, these data provide insights into the diminished effectiveness of influenza vaccines across vaccine seasons.

immunology↗

bioRxiv2021

Immunisation of ferrets and mice with recombinant SARS-CoV-2 spike protein formulated with Advax-SM adjuvant protects against COVID-19 infection

The development of a safe and effective vaccine is a key requirement to overcoming the COVID-19 pandemic. Recombinant proteins represent the most reliable and safe vaccine approach but generally require a suitable adjuvant for robust and durable immunity. We used the SARS-CoV-2 genomic sequence and in silico structural modelling to design a recombinant spike protein vaccine (Covax-19). A synthetic gene encoding the spike extracellular domain (ECD) was inserted into a baculovirus backbone to express the protein in insect cell cultures. The spike ECD was formulated with Advax-SM adjuvant and first tested for immunogenicity in C57BL/6 and BALB/c mice. The Advax-SM adjuvanted vaccine induced high titers of binding antibody against spike protein that were able to neutralise the original wildtype virus on which the vaccine was based as well as the variant B.1.1.7 lineage virus. The Covax-19 vaccine also induced potent spike-specific CD4+ and CD8+ memory T-cells with a dominant Th1 phenotype, and this was shown to be associated with cytotoxic T lymphocyte killing of spike labelled target cells in vivo. Ferrets immunised with Covax-19 vaccine intramuscularly twice 2 weeks apart made spike receptor binding domain (RBD) IgG and were protected against an intranasal challenge with SARS-CoV-2 virus 2 weeks after the second immunisation. Notably, ferrets that received two 25 or 50g doses of Covax-19 vaccine had no detectable virus in their lungs or in nasal washes at day 3 post-challenge, suggesting the possibility that Covax-19 vaccine may in addition to protection against lung infection also have the potential to block virus transmission. This data supports advancement of Covax-19 vaccine into human clinical trials.

immunology↗

bioRxiv2021

Connectivity profile laterality in corticostriatal functional circuitry: a fingerprinting approach

An abnormal magnitude of hemispheric difference (i.e. laterality) in corticostriatal circuits is a shared feature of numerous neurodevelopmental and psychiatric disorders. Detailed quantitation and regional localization of corticostriatal laterality in normative samples stands to further the understanding of hemispheric differences in healthy and disease states. Here, we used a fingerprinting approach to quantify "functional connectivity profile laterality" - the overall magnitude by which a voxels profile of connectivity with homotopic regions of the ipsilateral and contralateral cortex differs - in the striatum. Laterality magnitude heatmaps revealed "laterality hotspots" - constituting outliers in the voxel-wise distribution -in the right ventrolateral putamen and left central caudate. Findings were replicated in an independent sample, with significant (p<0.05) spatial overlap observed between the location of the laterality hotspots across samples, as measured via Dice coefficients. At both hotspots, a primary driver of overall laterality was the difference in striatal connectivity strength with the right and left pars opercularis of the inferior frontal gyrus. Right and left striatum laterality magnitude maps were found to significantly differ (p<0.05) at the hotspot locations. Moreover, using subjects left, but not right, striatum laterality magnitude maps, a support vector machine trained on a discovery sample (n=77) and tested on a replication sample (n=77) significantly predicted (r=0.25, p=0.028) subject performance on a language task, known for its lateralized nature. Laterality magnitude maps remained consistent across different cortical atlas parcellations and did not differ significantly between right-handed and left-handed individuals. In sum, meaningful variation in functional connectivity profile laterality - both spatially within the striatum and across subjects - is evident in corticostriatal circuits. Findings provide a basis to examine corticostriatal connectivity profile laterality in psychiatric illness.

neuroscience↗

bioRxiv2020

Age-dependent glycomic response to the 2009 pandemic H1N1 influenza virus and its association with disease severity

Influenza A viruses cause a spectrum of responses, from mild cold-like symptoms to severe respiratory illness and death. Viral strains and intrinsic host factors, such as age, can influence the severity of the disease. Glycosylation plays a critical role in influenza pathogenesis, however the molecular drivers of influenza outcomes remain unknown. In this work, we characterized the glycomic response to the H1N1 2009 pandemic influenza A virus in age-dependent severity. Using a ferret model and a lectin microarray technology we have developed, we compared responses in newly weaned and aged animals, a model for young children and the elderly, respectively. Glycomic analysis revealed changes in glycosylation over the course of the infection, that were associated with severity in an age-dependent manner. These responses may help explain the differential susceptibility to influenza A virus infection of young children and the elderly. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=98 SRC="FIGDIR/small/165613v1_ufig1.gif" ALT="Figure 1"> View larger version (20K): org.highwire.dtl.DTLVardef@1c5aebdorg.highwire.dtl.DTLVardef@15316e6org.highwire.dtl.DTLVardef@45ff3org.highwire.dtl.DTLVardef@1376533_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

bioRxiv2020

Glycomic analysis of host-response reveals high mannose as a key mediator of influenza severity

Influenza virus infections cause a wide variety of outcomes, from mild disease to 3-5 million cases of severe illness and ~290,000-645,000 deaths annually worldwide. The molecular mechanisms underlying these disparate outcomes are currently unknown. Glycosylation within the human host plays a critical role in influenza virus biology. However, the impact these modifications have on the severity of influenza disease has not been examined. Herein, we profile the glycomic host responses to influenza virus infection as a function of disease severity using a ferret model and our lectin microarray technology. We identify the glycan epitope high mannose as a marker of influenza virus-induced pathogenesis and severity of disease outcome. Induction of high mannose is dependent upon the unfolded protein response (UPR) pathway, a pathway previously shown to associate with lung damage and severity of influenza virus infection. Also, the mannan-binding lectin (MBL2), an innate immune lectin that negatively impacts influenza outcomes, recognizes influenza virus-infected cells in a high mannose dependent manner. Together, our data argue that the high mannose motif is an infection-associated molecular pattern on host cells that may guide immune responses leading to the concomitant damage associated with severity. SIGNIFICANCEInfluenza virus infection causes a range of outcomes from mild illness to death. The molecular mechanisms leading to these differential host responses are currently unknown. Herein, we identify the induction of high mannose, a glycan epitope, as a key mediator of severe disease outcome. We propose a mechanism in which activation of the unfolded protein response (UPR) upon influenza virus infection turns on expression of high mannose, which is then recognized by the innate immune lectin MBL2, activating the complement cascade and leading to subsequent inflammation. This work is the first to systematically study host glycomic changes in response to influenza virus infection, identifying high mannose as a key feature of differential host response.

microbiology↗

bioRxiv2019

Influenza preimmunity increases vaccination efficacy by influencing antibody longevity,neutralization activity, and epitope specificity

Influenza virus infections are a recurrent public health problem causing millions of hospitalizations each year despite vaccination efforts. The well-known yearly cycling of influenza viruses is the result of the reciprocal and coevolutionary relationship between the host and virus. Together, from the frequent infections and yearly vaccinations humans build a complex immune history over their lifetimes. Despite the prominence of immune history, vaccines are rarely evaluated in the imprinted (preimmune) host. We developed a ferret model for this purpose where ferrets were imprinted with a sublethal dose of the historical seasonal H1N1 strain A/USSR/90/1977 (USSR/77). A +60 day recovery period was given to build immune memory prior to vaccination with a split virion QIV vaccine. To evaluate protection, the ferrets were challenged with a 2009 H1N1 pandemic virus matching the vaccine antigens. The preimmune-vaccinated ferrets did not experience significant disease during challenge while the naive-vaccinated group were the most severe. Hemagglutination inhibition (HAI) assays showed that preimmune ferrets had a faster and longer antibody response post vaccination for all vaccine antigens compared to minimal HAI responses in the naive-vaccinated group. To investigate the immune mechanisms leading to disease protection in the preimmune ferrets, we performed microneutralization and isotype ELISA assays. Microneutralization suggested preimmune ferrets developed antibodies that were more functional for virus neutralization. Antibody isotype profiling indicated that virus specific antibodies in the preimmune-vaccinated ferrets was dominated by the IgG isotype suggesting B cell maturity and possible plasticity in a pre-existing B cell. Surprisingly, the naive-vaccinated ferrets developed a more severe disease with less virus neutralization suggesting improper immunological processing of vaccine antigens. Together, these results showed the preimmune host had greater responses to vaccination, and the predominant IgG virus specific antibodies suggested a flexible long-lived B cell response. These results are important and should be considered for vaccine design.\n\nAUTHOR SUMMARYThe influenza virus is a significant threat to human health and the economy despite large-scale vaccination efforts. The low effectiveness of the seasonal influenza vaccine is attributed to the frequently mutating virus enabling people to have several influenza virus infections throughout their lifetimes. As people are susceptible to multiple infections, they build a complex immune history. Despite this, vaccines are often not evaluated in animals with an immune history. Here we developed a ferret model that had previously been infected with a historical influenza virus to evaluate vaccine responses to current vaccines. Ferrets were infected with a sublethal does of a historical virus, A/USSR/90/1977, to develop a preimmune background. Preimmune ferrets were vaccinated with the Sanofi quadrivalent influenza vaccine and the antibody responses were investigated after vaccination. Our results showed that preimmune ferrets had a stronger antibody response following vaccination and the antibodies developed were older and better at neutralizing influenza virus at a virus challenge. Clinically, preimmune-vaccinated ferrets developed a milder disease during challenge compared to naive-vaccinated ferrets. This work indicates that the host responses to vaccination are dependent on the host background and that influenza vaccine development and evaluation should take host influenza background into account.

microbiology↗