Biology subjects

Agostino, C. J.

Publications and source records attributed to Agostino, C. J..

4 recordsLinked to original sources

bioRxiv2025

Machine learning enables de novo multi-epitope design of plasmodium falciparum circumsporozoite protein to target trimeric L9 antibody

AbstractCurrently approved vaccines for the prevention of malaria provide only partial protection against disease, due to high variability in the quality of induced antibodies. These vaccines present the unstructured central repeat region, as well as the C-terminal domain, of the circumsporozoite protein (PfCSP) of the malaria parasite, Plasmodium falciparum (1). A recently discovered protective monoclonal antibody, L9, recognizes three structured copies of the PfCSP minor repeat. Similarly to other highly potent anti-malarial antibodies, L9 relies on critical homotypic interactions between antibodies for its high protective efficacy (2, 3). Here, we report the design of immunogens scaffolding one copy of PfCSPs minor repeat capable of binding L9. To design immunogens capable of presenting multiple, structure-based epitopes in one scaffold, we developed a machine-learning-driven structural immunogen design pipeline, MESODID, tailored to focus on multi-epitope vaccine targets. We use this pipeline to design multiple scaffolds that present three copies of the PfCSP minor repeat. A 3.6 [A] cryo-EM structure of our top design, minor repeat targeting immunogen (M-TIM), demonstrates that M-TIM successfully orients three copies of L9, effectively recapitulating its critical homotypic interactions. The wide prevalence of repeated epitopes in key vaccine targets, such as HIV-1 Envelope, SARS-CoV-2 spike, and Influenza Hemagglutinin, suggests that MESODID will have broad utility in creating immunogens that incorporate such epitopes, offering a new powerful approach to developing vaccines against a range of challenging infections, including malaria. Significance StatementIn this study, we present a machine learning driven, structure-guided protein design pipeline built specifically for the design of multi-epitope vaccine immunogens. We employ the pipeline here to design and solve the cryo-EM structure of a de novo immunogen that binds and properly orients three copies of the anti-malarial monoclonal antibody L9, producing a promising next-generation malaria vaccine immunogen. This design pipeline could be employed to design any number of structurally constrained multi-epitope immunogens, as well as other proteins designed to bind multiple targets.

biophysics↗

bioRxiv2025

Env-antibody coevolution identifies B cell priming as the principal bottleneck to HIV-1 V2 apex broadly neutralizing antibody development

Broadly neutralizing antibodies (bNAbs) are rarely elicited during HIV-1 infection. To identify obstacles to bNAb development, we longitudinally studied 122 rhesus macaques infected by one of 16 different simian-human immunodeficiency viruses (SHIVs). We identified V2 apex as the most common bNAb target and a subset of Envs that preferentially elicited these antibodies. In 10 macaques, we delineated Env-antibody coevolution from B cell priming to bNAb development. Antibody phylogenies revealed permissive developmental pathways guided by evolving Envs that contained few mutations in or near the V2 apex C-strand, which were a sensitive indicator of apex-targeted responses. The absence of such mutations reflected a failure in bNAb priming. These results indicate that efficiency of B cell priming, and not complexities in Env-guided affinity maturation, is the primary obstacle to V2 apex bNAb elicitation in SHIV-infected macaques and identify specific HIV-1 Envs to advance as novel vaccine platforms. One sentence summaryB cell priming is the primary bottleneck to HIV-1 V2 apex bNAb elicitation.

immunology↗

bioRxiv2024

Deep Mining of the Human Antibody Repertoire Identifies Frequent and Immunogenetically Diverse CDRH3 Topologies Targetable by Vaccination

Germline targeting vaccination strategies against highly variable pathogens such as HIV aim to elicit broadly neutralizing antibodies (bnAbs) with particular immunogenetic or structural features. The V2 apex of the HIV Env protein is a promising target for a class of bnAbs that contain conserved structural motifs in the heavy chain complementarity determining region 3 (CDRH3). Here, we show that these structural motifs are targetable by vaccination by characterizing V2 apex axe-like CDRH3s in the human repertoire and developing new immunogens capable of engaging them. We determined the frequency and diversity of axe-like CDHR3s in healthy human donors using a series of structural informatics approaches, finding these precursors in nearly 90% of donors. Axe-targeting immunogens based on the HIV Env Q23.17 bound axe-like precursors in cryo-EM structures, induced V2 apex-specific antibody responses in humanized mice, and induced axe-like heterologous neutralizing antibodies in rhesus macaques infected with a germline-targeted simian-human immunodeficiency virus. These results illustrate a new structure-guided immunoinformatic vaccine design paradigm that can be employed to elicit immunogenetically diverse yet structurally conserved classes of antibodies. Significance StatementMany broadly neutralizing antibodies (bnAbs) utilize modes of epitope recognition dominated by the antibody complementarity determining region 3 (CDRH3). The CDRH3 is the most diverse part of the antibody, posing a challenge for germline targeting vaccine designs that aim to elicit antibodies with particular immunogenetic features. Vaccine design strategies that accommodate CDRH3 variability are therefore needed. Many HIV Env V2 apex bnAbs share "axe-like" CDRH3 microfolds that arise from diverse immunogenetic origins. Here we determined the frequency in humans of B cells with such CDRH3 topologies and designed immunogens to engage their precursors. This work opens a path toward vaccines that engage specific structural classes of B cells, thereby advancing the rational design of immunogens for HIV and other pathogens.

immunology↗

bioRxiv2023

Homologous mutations in β, embryonic, and perinatal muscle myosins have divergent effects on molecular power generation

Mutations at a highly conserved homologous residue in three closely related muscle myosins cause three distinct diseases involving muscle defects: R671C in {beta}-cardiac myosin causes hypertrophic cardiomyopathy, R672C and R672H in embryonic skeletal myosin cause Freeman Sheldon syndrome, and R674Q in perinatal skeletal myosin causes trismus- pseudocamptodactyly syndrome. It is not known if their effects at the molecular level are similar to one another or correlate with disease phenotype and severity. To this end, we investigated the effects of the homologous mutations on key factors of molecular power production using recombinantly expressed human {beta}, embryonic, and perinatal myosin subfragment-1. We found large effects in the developmental myosins, with the most dramatic in perinatal, but minimal effects in {beta} myosin, and magnitude of changes correlated partially with clinical severity. The mutations in the developmental myosins dramatically decreased the step size and load-sensitive actin-detachment rate of single molecules measured by optical tweezers, in addition to decreasing ATPase cycle rate. In contrast, the only measured effect of R671C in {beta} myosin was a larger step size. Our measurements of step size and bound times predicted velocities consistent with those measured in an in vitro motility assay. Finally, molecular dynamics simulations predicted that the arginine to cysteine mutation in embryonic, but not {beta}, myosin may reduce pre-powerstroke lever arm priming and ADP pocket opening, providing a possible structural mechanism consistent with the experimental observations. This paper presents the first direct comparisons of homologous mutations in several different myosin isoforms, whose divergent functional effects are yet another testament to myosins highly allosteric nature.

biophysics↗