Biology subjects

Wilson, I. A.

Publications and source records attributed to Wilson, I. A..

5 recordsLinked to original sources

bioRxiv2018

Potent anti-influenza H7 human monoclonal antibody induces separation of hemagglutinin receptor binding head domains

Seasonal influenza virus infections can cause significant morbidity and mortality, but the threat from emergence of a new pandemic influenza strain might have potentially even more devastating consequences. As such, there is intense interest in isolating and characterizing potent neutralizing antibodies that target the hemagglutinin (HA) viral surface glycoprotein. Here, we use cryo-electron microscopy to decipher the mechanism of action of a potent HA head-directed monoclonal antibody bound to an influenza H7 HA. The epitope of the antibody is not solvent accessible in the compact, pre-fusion conformation that typifies all HA structures to date. Instead, the antibody binds between HA head protomers to an epitope that must be partly or transiently exposed in the pre-fusion conformation. The \"breathing\" of the HA protomers is implied by the exposure of this epitope, which is consistent with metastability of class I fusion proteins. This structure likely therefore represents an early structural intermediate in the viral fusion process. Understanding the extent of transient exposure of conserved neutralizing epitopes also may lead to new opportunities to combat influenza that have not been appreciated previously.\n\nAuthor SummaryA transiently exposed epitope on influenza H7 hemagglutinin represents a new target for neutralizing antibodies.

immunology↗

bioRxiv2018

HIV-1 vaccine design through minimizing envelope metastability

Overcoming envelope metastability is crucial to trimer-based HIV-1 vaccine design. Here, we present a coherent vaccine strategy by minimizing metastability. For ten strains across five clades, we demonstrate that gp41 ectodomain (gp41ECTO) is the main source of envelope metastability by replacing wild-type gp41ECTO with BG505 gp41ECTO of the uncleaved prefusion-optimized (UFO) design. These gp41ECTO-swapped trimers can be produced in CHO cells with high yield and high purity. Crystal structure of a gp41ECTO-swapped trimer elucidates how a neutralization-resistant tier 3 virus evades antibody recognition of the V2 apex. UFO trimers of transmitted/founder (T/F) viruses and UFO trimers containing a consensus-based ancestral gp41ECTO suggest an evolutionary root of the metastability. Gp41ECTO-stabilized trimers can be readily displayed on 24- and 60-meric nanoparticles, with incorporation of additional T cell help illustrated for a hyperstable 60-mer. In mice and rabbits, gp140 nanoparticles induced more effective tier 2 neutralizing antibody response than trimers with statistical significance.\n\nHIGHLIGHTSO_LIgp41 is the main source of HIV-1 envelope metastability\nC_LIO_LIBG505 gp41 of the UFO design stabilizes gp140 trimers of diverse subtypes\nC_LIO_LIgp41 stabilization facilitates gp140 nanoparticle assembly and improves production\nC_LIO_LINanoparticles elicit tier 2 neutralizing antibodies more effectively than trimers\nC_LI

microbiology↗

bioRxiv2018

Cryo-EM structure of the circumsporozoite protein of Plasmodium falciparum with a vaccine-elicited antibody reveals maturation of inter-antibody contacts

The circumsporozoite protein (CSP) on the surface of Plasmodium falciparum sporozoites is important for parasite development, motility, and host hepatocyte invasion. However, intrinsic disorder of the NANP repeat sequence in the central region of CSP has hindered its structural and functional characterization. Here, the cryo-EM structure at [~]3.4 [A] resolution of a recombinant shortened CSP construct (rsCSP) with the variable domains (Fabs) of a highly protective monoclonal antibody reveals an extended spiral conformation of the central NANP repeat region surrounded by antibodies. This unusual structure appears to be stabilized and/or induced by interaction with an antibody where contacts between adjacent Fabs are somatically mutated and enhance the interaction. Such maturation in non-antigen contact residues may be an effective mechanism for antibodies to target tandem repeat sequences and provide novel insights into malaria vaccine design.\n\nSummaryAn unusual spiral conformation is formed for the NANP repeat region in Plasmodium falciparum circumsporozoite protein (CSP) in complex with antibodies generated by the RTS,S vaccine and is stabilized by affinity-matured inter-Fab interactions.

immunology↗

bioRxiv2018

Bacterial Glycosyltransferase-mediated Cell-surface Chemoenzymatic Glycan Editing: Methods and Applications

AbstractChemoenzymatic glycan editing that modifies glycan structures directly on the cell surface has emerged as a complementary tool to metabolic oligosaccharide engineering. In this article, we report the discovery that three bacterial enzymes--Pasteurella multocida 2-3-sialyltransferase M144D mutant (Pm2,3ST-M144D), Photobacterium damsel 2-6-sialyltransferase (Pd2,6ST) and Helicobacter mustelae 1-2-fucosyltransferase (Hm1,2FT)--can serve as highly efficient tools for cell-surface glycan editing. Among these three enzymes, the two sialyltransferases were also found to be tolerant to large substituents introduced to the C-5 position of the cytidine monophosphate N-acetylneuraminic acid donor, including biotin and fluorescent dyes. Combining these enzymes with our previously discovered Helicobacter pylori 1-3-FT, we developed a live cell-based assay to probe host-cell glycan-mediated influenza A virus (IAV) infection including both wild-type and mutant strains of human H1N1 and H3N2 influenza subtypes. At high SiaNAc2-6-Gal levels, the ability of a viral strain to induce the host cell death is positively correlated with the SiaNAc2-6-Gal binding affinity of its haemagglutinin. Surprisingly, the creation of sLeX on the host cell surface via in situ 1-3-Fuc editing also exacerbated the killing induced by several wild-type IAV strains as well as a mutant known as HK68-MTA. Structural alignment of HAs from the wild-type HK68 and HK68-MTA revealed the formation of a putative hydrogen bond between Trp222 of HA-HK68-MTA and the C-4 hydroxyl group of the 1-3-linked fucose of sLeX. This interaction is likely to be responsible for the better binding affinity of HA-HK68-MTA to sLeX and accordingly the enhanced host-cell killing compared with the wild-type HK68.

biochemistry↗

bioRxiv2018

Common antigenic motif recognized by human VH5-51/VL4-1 tau antibodies with distinct functionalities

Misfolding and aggregation of tau protein are closely associated with the onset and progression of Alzheimers Disease (AD). By interrogating IgG+ memory B cells from asymptomatic donors with tau peptides, we have identified two somatically mutated VH5-51/VL4-1 antibodies. One of these, CBTAU-27.1, binds to the aggregation motif in the R3 repeat domain and blocks the aggregation of tau into paired helical filaments (PHFs) by sequestering monomeric tau. The other, CBTAU-28.1, binds to the N-terminal insert region and inhibits the spreading of tau seeds and mediates the uptake of tau aggregates into microglia by binding PHFs. Crystal structures revealed that the combination of VH5-51 and VL4-1 recognizes a common Pro-Xn-Lys motif driven by germline-encoded hotspot interactions while the specificity and thereby functionality of the antibodies are defined by the CDR3 regions. Affinity improvement led to improvement in functionality, identifying their epitopes as new targets for therapy and prevention of AD.

neuroscience↗