14 research outputs found
Multivalent antigen arrays exhibit high avidity binding and modulation of B cell receptor-mediated signaling to drive efficacy against experimental autoimmune encephalomyelitis
This document is the Accepted Manuscript version of a Published Work that appeared in final form in
Biomacromolecules, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.biomac.7b00335.A pressing need exists for antigen-specific immunotherapies (ASIT) that induce selective tolerance in autoimmune disease while avoiding deleterious global immunosuppression. Multivalent soluble antigen arrays (SAgAPLP:LABL), consisting of a hyaluronic acid (HA) linear polymer backbone co-grafted with multiple copies of autoantigen (PLP) and cell adhesion inhibitor (LABL) peptides, are designed to induce tolerance to a specific multiple sclerosis (MS) autoantigen. Previous studies established that hydrolyzable SAgAPLP:LABL, employing a degradable linker to codeliver PLP and LABL, was therapeutic in experimental autoimmune encephalomyelitis (EAE) in vivo and exhibited antigen-specific binding with B cells, targeted the B cell receptor (BCR), and dampened BCR-mediated signaling in vitro. Our results pointed to sustained BCR engagement as the SAgAPLP:LABL therapeutic mechanism, so we developed a new version of the SAgA molecule using non-hydrolyzable conjugation chemistry, hypothesizing it would enhance and maintain the moleculeâs action at the cell surface to improve efficacy. âClick SAgAâ (cSAgAPLP:LABL) uses hydrolytically stable covalent conjugation chemistry (Copper-catalyzed Azide-Alkyne Cycloaddition (CuAAC)) rather than a hydrolyzable oxime bond to attach PLP and LABL to HA. We explored cSAgAPLP:LABL B cell engagement and modulation of BCR-mediated signaling in vitro through flow cytometry binding and calcium flux signaling assays. Indeed, cSAgAPLP:LABL exhibited higher avidity B cell binding and greater dampening of BCR-mediated signaling than hydrolyzable SAgAPLP:LABL. Furthermore, c SAgAPLP:LABL exhibited significantly enhanced in vivo efficacy compared to hydrolyzable SAgAPLP:LABL, achieving equivalent efficacy at one quarter of the dose. These results indicate that non-hydrolyzable conjugation increased the avidity of cSAgAPLP:LABL to drive in vivo efficacy through modulated BCR-mediated signaling.NIH T32 GM008545Madison and Lila Self Graduate Fellowship at the University of KansasHoward Rytting pre-doctoral fellowship from the Department of Pharmaceutical Chemistry at the University of Kansa
Factors influencing terrestriality in primates of the Americas and Madagascar
Among mammals, the order Primates is exceptional in having a high taxonomic richness in which the taxa are arboreal, semiterrestrial, or terrestrial. Although habitual terrestriality is pervasive among the apes and African and Asian monkeys (catarrhines), it is largely absent among monkeys of the Americas (platyrrhines), as well as galagos, lemurs, and lorises (strepsirrhines), which are mostly arboreal. Numerous ecological drivers and species-specific factors are suggested to set the conditions for an evolutionary shift from arboreality to terrestriality, and current environmental conditions may provide analogous scenarios to those transitional periods. Therefore, we investigated predominantly arboreal, diurnal primate genera from the Americas and Madagascar that lack fully terrestrial taxa, to determine whether ecological drivers (habitat canopy cover, predation risk, maximum temperature, precipitation, primate species richness, human population density, and distance to roads) or species-specific traits (bodymass, group size, and degree of frugivory) associate with increased terrestriality. We collated 150,961 observation hours across 2,227 months from 47 species at 20 sites in Madagascar and 48 sites in the Americas. Multiple factors were associated with ground use in these otherwise arboreal species, including increased temperature, a decrease in canopy cover, a dietary shift away from frugivory, and larger group size. These factors mostly explain intraspecific differences in terrestriality. As humanity modifies habitats and causes climate change, our results suggest that species already inhabiting hot, sparsely canopied sites, and exhibiting more generalized diets, are more likely to shift toward greater ground use
Factors influencing terrestriality in primates of the Americas and Madagascar
Among mammals, the order Primates is exceptional in having a high taxonomic richness in which the taxa are arboreal, semiterrestrial, or terrestrial. Although habitual terrestriality is pervasive among the apes and African and Asian monkeys (catarrhines), it is largely absent among monkeys of the Americas (platyrrhines), as well as galagos, lemurs, and lorises (strepsirrhines), which are mostly arboreal. Numerous ecological drivers and species-specific factors are suggested to set the conditions for an evolutionary shift from arboreality to terrestriality, and current environmental conditions may provide analogous scenarios to those transitional periods. Therefore, we investigated predominantly arboreal, diurnal primate genera from the Americas and Madagascar that lack fully terrestrial taxa, to determine whether ecological drivers (habitat canopy cover, predation risk, maximum temperature, precipitation, primate species richness, human population density, and distance to roads) or species-specific traits (body mass, group size, and degree of frugivory) associate with increased terrestriality. We collated 150,961 observation hours across 2,227 months from 47 species at 20 sites in Madagascar and 48 sites in the Americas. Multiple factors were associated with ground use in these otherwise arboreal species, including increased temperature, a decrease in canopy cover, a dietary shift away from frugivory, and larger group size. These factors mostly explain intraspecific differences in terrestriality. As humanity modifies habitats and causes climate change, our results suggest that species already inhabiting hot, sparsely canopied sites, and exhibiting more generalized diets, are more likely to shift toward greater ground use
Multivalent Soluble Antigen Arrays Exhibit High Avidity Binding and Modulation of B Cell Receptor-Mediated Signaling to Drive Efficacy against Experimental Autoimmune Encephalomyelitis
A pressing need exists
for antigen-specific immunotherapies (ASIT)
that induce selective tolerance in autoimmune disease while avoiding
deleterious global immunosuppression. Multivalent soluble antigen
arrays (SAgA<sub>PLP:LABL</sub>), consisting of a hyaluronic acid
(HA) linear polymer backbone cografted with multiple copies of autoantigen
(PLP) and cell adhesion inhibitor (LABL) peptides, are designed to
induce tolerance to a specific multiple sclerosis (MS) autoantigen.
Previous studies established that hydrolyzable SAgA<sub>PLP:LABL</sub>, employing a degradable linker to codeliver PLP and LABL, was therapeutic
in experimental autoimmune encephalomyelitis (EAE) in vivo and exhibited
antigen-specific binding with B cells, targeted the B cell receptor
(BCR), and dampened BCR-mediated signaling in vitro. Our results pointed
to sustained BCR engagement as the SAgA<sub>PLP:LABL</sub> therapeutic
mechanism, so we developed a new version of the SAgA molecule using
nonhydrolyzable conjugation chemistry, hypothesizing it would enhance
and maintain the moleculeâs action at the cell surface to improve
efficacy. âClick SAgAâ (cSAgA<sub>PLP:LABL</sub>) uses
hydrolytically stable covalent conjugation chemistry (Copper-catalyzed
AzideâAlkyne Cycloaddition (CuAAC)) rather than a hydrolyzable
oxime bond to attach PLP and LABL to HA. We explored cSAgA<sub>PLP:LABL</sub> B cell engagement and modulation of BCR-mediated signaling in vitro
through flow cytometry binding and calcium flux signaling assays.
Indeed, cSAgA<sub>PLP:LABL</sub> exhibited higher avidity B cell binding
and greater dampening of BCR-mediated signaling than hydrolyzable
SAgA<sub>PLP:LABL</sub>. Furthermore, cSAgA<sub>PLP:LABL</sub> exhibited
significantly enhanced in vivo efficacy compared to hydrolyzable SAgA<sub>PLP:LABL</sub>, achieving equivalent efficacy at one-quarter of the
dose. These results indicate that nonhydrolyzable conjugation increased
the avidity of cSAgA<sub>PLP:LABL</sub> to drive in vivo efficacy
through modulated BCR-mediated signaling
To leave or not to leave: American Association for the Surgery of Trauma (AAST) panel discussion on personal, parental, and family leave
Navigating planned and emergent leave during medical practice is very confusing to most physicians. This is especially challenging to the trauma and acute care surgeon, whose practice is unique due to overnight in-hospital call, alternating coverage of different services, and trauma centerâs staffing challenges. This is further compounded by a surgical culture that promotes the image of a âtoughâ surgeon and forgoing oneâs personal needs on behalf of patients and colleagues. Frequently, surgeons find themselves having to make a choice at the crossroads of personal and family needs with work obligations: to leave or not to leave. Often, surgeons prioritize their professional commitment over personal wellness and family support. Extensive research has been conducted on the topic of maternity leave and inequality towards female surgeons, primarily focused on trainees. The value of paternity leave has been increasingly recognized recently. Consequently, significant policy changes have been implemented to support trainees. Practicing surgeon, however, often lack such policy support, and thus may default to local culture or contractual agreement. A panel session at the American Association for the Surgery of Trauma 2022 annual meeting was held to discuss the current status of planned or unanticipated leave for practicing surgeons. Experiences, perspectives, and propositions for change were discussed, and are presented here
Antigen-Specific Binding of Multivalent Soluble Antigen Arrays Induces Receptor Clustering and Impedes B Cell Receptor Mediated Signaling
A pressing
need exists for autoimmune disease therapies that act
in an antigen-specific manner while avoiding global immunosuppression.
Multivalent soluble antigen arrays (SAgA<sub>PLP:LABL</sub>), designed
to induce tolerance to a specific multiple sclerosis autoantigen,
consist of a flexible hyaluronic acid (HA) polymer backbone cografted
with multiple copies of autoantigen peptide (PLP) and cell adhesion
inhibitor peptide (LABL). Previous in vivo studies revealed copresentation
of both signals on HA was necessary for therapeutic efficacy. To elucidate
therapeutic cellular mechanisms, in vitro studies were performed in
a model B cell system to evaluate binding and specificity. Compared
to HA and HA arrays containing only grafted PLP or LABL, SAgA<sub>PLP:LABL</sub> displaying both PLP and LABL exhibited greatly enhanced
B cell binding. Furthermore, the binding avidity of SAgA<sub>PLP:LABL</sub> was primarily driven by the PLP antigen, determined via flow cytometry
competitive dissociation studies. Fluorescence microscopy showed SAgA<sub>PLP:LABL</sub> induced mature receptor clustering that was faster
than other HA arrays with only one type of grafted peptide. SAgA<sub>PLP:LABL</sub> molecules also reduced and inhibited IgM-stimulated
signaling as discerned by a calcium flux assay. The molecular mechanisms
of enhanced antigen-specific binding, mature receptor clustering,
and dampened signaling observed in B cells may contribute to SAgA<sub>PLP:LABL</sub> therapeutic efficacy
Molecular Dynamics of Multivalent Soluble Antigen Arrays Support a Two-Signal Co-delivery Mechanism in the Treatment of Experimental Autoimmune Encephalomyelitis
Many
current therapies for autoimmune diseases such as multiple
sclerosis (MS) result in global immunosuppression, rendering insufficient
efficacy with increased risk of adverse side effects. Multivalent
soluble antigen arrays, nanomaterials presenting both autoantigen
and secondary inhibitory signals on a flexible polymer backbone, are
hypothesized to shift the immune response toward selective autoantigenic
tolerance to repress autoimmune disease. Two-signal co-delivery of
both autoantigen and secondary signal were deemed necessary for therapeutic
efficacy against experimental autoimmune encephalomyelitis, a murine
model of MS. Dynamic light scattering and in silico molecular dynamics
simulations complemented these studies to illuminate the role of two-signal
co-delivery in determining therapeutic potential. Physicochemical
characteristics such as particle size and molecular affinity for intermolecular
interactions and chain entanglement likely facilitated cotransport
of two signals to produce efficacy. These findings elucidate potential
mechanisms whereby soluble antigen arrays enact their therapeutic
effect and help to guide the development of future multivalent antigen-specific
immunotherapies
Combined PET and whole-tissue imaging of lymphatic-targeting vaccines in non-human primates
Antigen accumulation in lymph nodes (LNs) is critical for vaccine efficacy, but understanding of vaccine biodistribution in humans or large animals remains limited. Using the rhesus macaque model, we employed a combination of positron emission tomography (PET) and fluorescence imaging to characterize the whole-animal to tissue-level biodistribution of a subunit vaccine comprised of an HIV envelope trimer protein nanoparticle (trimer-NP) and lipid-conjugated CpG adjuvant (amph-CpG). Following immunization in the thigh, PET imaging revealed vaccine uptake primarily in inguinal and iliac LNs, reaching distances up to 17Â cm away from the injection site. Within LNs, trimer-NPs exhibited striking accumulation on the periphery of follicular dendritic cell (FDC) networks in B cell follicles. Comparative imaging of soluble Env trimers (not presented on nanoparticles) in naĂŻve or previously-immunized animals revealed diffuse deposition of trimer antigens in LNs following primary immunization, but concentration on FDCs in pre-immunized animals with high levels of trimer-specific IgG. These data demonstrate the capacity of nanoparticle or "albumin hitchhiking" technologies to concentrate vaccines in genitourinary tract-draining LNs, which may be valuable for promoting mucosal immunity
Intranasal vaccination with lipid-conjugated immunogens promotes antigen transmucosal uptake to drive mucosal and systemic immunity
To combat the HIV epidemic and emerging threats such as SARS-CoV-2, immunization strategies are needed that elicit protection at mucosal portals of pathogen entry. Immunization directly through airway surfaces is effective in driving mucosal immunity, but poor vaccine uptake across the mucus and epithelial lining is a limitation. The major blood protein albumin is constitutively transcytosed bidirectionally across the airway epithelium through interactions with neonatal Fc receptors (FcRn). Exploiting this biology, here, we demonstrate a strategy of âalbumin hitchhikingâ to promote mucosal immunity using an intranasal vaccine consisting of protein immunogens modified with an amphiphilic albumin-binding polymer-lipid tail, forming amph-proteins. Amph-proteins persisted in the nasal mucosa of mice and nonhuman primates and exhibited increased uptake into the tissue in an FcRn-dependent manner, leading to enhanced germinal center responses in nasal-associated lymphoid tissue. Intranasal immunization with amph-conjugated HIV Env gp120 or SARS-CoV-2 receptor binding domain (RBD) proteins elicited 100- to 1000-fold higher antigen-specific IgG and IgA titers in the serum, upper and lower respiratory mucosa, and distal genitourinary mucosae of mice compared to unmodified protein. Amph-RBD immunization induced high titers of SARS-CoV-2âneutralizing antibodies in serum, nasal washes, and bronchoalveolar lavage. Furthermore, intranasal amph-protein immunization in rhesus macaques elicited 10-fold higher antigen-specific IgG and IgA responses in the serum and nasal mucosa compared to unmodified protein, supporting the translational potential of this approach. These results suggest that using amph-protein vaccines to deliver antigen across mucosal epithelia is a promising strategy to promote mucosal immunity against HIV, SARS-CoV-2, and other infectious diseases.</jats:p