Biology subjects

Kapingidza, A. B.

Publications and source records attributed to Kapingidza, A. B..

4 recordsLinked to original sources

bioRxiv2025

Iterative immunogen optimization to focus elicited responses on a conserved, subdominant influenza hemagglutinin epitope

Designing effective vaccination strategies against genetically diverse viruses, such as HIV or influenza, is hindered by the ability of these pathogens to mutate and readily evade immune responses. While these viruses contain conserved regions that cannot easily mutate without affecting viral fitness, these sites are subdominant, meaning that they are not the primary target of antibodies elicited by natural infection or current vaccines. Here, we integrated recent advances in machine learning methods for protein structure prediction and design to engineer protein immunogens that focus immune responses on a conserved, subdominant HA epitope targeted by broadly cross-reactive influenza antibodies. Iterating between computation-guided optimization and in vivo analyses generated immunogens that faithfully displayed the target epitope and redirected humoral responses toward it upon vaccination. These results provide a blueprint for applying recent protein engineering approaches to immunogen design and may inform the development of broadly protective influenza vaccines.

immunology↗

bioRxiv2025

Design of SARS-CoV-2 RBD Immunogens to Focus Immune Responses Towards Conserved Coronavirus Epitopes

SARS-CoV-2 continues to evolve, with new variants emerging that evade pre-existing immunity and limit the efficacy of existing vaccines. One approach towards developing superior, variant-proof vaccines is to engineer immunogens that preferentially elicit antibodies with broad cross-reactivity against SARS-CoV-2 and its variants by targeting conserved epitopes on spike. The inner and outer faces of the Receptor Binding Domain (RBD) are two such conserved regions targeted by antibodies that recognize diverse human and animal coronaviruses. To promote the elicitation of such antibodies by vaccination, we engineered "resurfaced" RBD immunogens that contained mutations at exposed RBD residues outside the target epitopes. In the context of pre-existing immunity, these vaccine candidates aim to disfavor the elicitation of strain-specific antibodies against the immunodominant Receptor Binding Motif (RBM) while boosting the induction of inner and outer face antibodies. The engineered resurfaced RBD immunogens were stable, lacked binding to monoclonal antibodies with limited breadth, and maintained strong interactions with target broadly neutralizing antibodies. When used as vaccines, they limited humoral responses against the RBM as intended. Multimerization on nanoparticles further increased the immunogenicity of the resurfaced RBDs immunogens, thus supporting resurfacing as a promising immunogen design approach to rationally shift natural immune responses to develop more protective vaccines.

immunology↗

bioRxiv2024

A high affinity monoclonal antibody against HLA-E-VL9 enhances natural killer cell anti-tumor killing

A major natural killer (NK) cell and CD8+ T cell checkpoint is mediated by the inhibitory receptor NKG2A/CD94 and its ligand, HLA-E complexed with 9 amino acid HLA-Ia leader sequence-derived peptides termed VL9 (HLA-E-VL9). Here, we used structure-based design and high throughput library screening to generate antibodies that block NKG2A/CD94 interactions, resulting in direct NK and CD8+ T cell cytotoxicity, and trigger NK cell antibody-dependent cellular cytotoxicity (ADCC). Anti-HLA-E-VL9 antibodies limited HLA-E-VL9+ tumor growth in mice, demonstrating checkpoint inhibition activity in vivo. HLA-E-VL9 was found to be expressed on HIV-infected cells, and its engagement by HLA-E-VL9 antibodies eliminated infected cells by NK-mediated ADCC. HLA-E-VL9 antibodies also enhanced the killing of HIV-infected cells by NKG2A/CD94+ CD8+ T cells targeting a novel HLA-E binding HIV Rev-derived epitope. Therefore, anti-HLA-E-VL9 antibodies represent a novel approach to eliminate pathogenic target cells by enhancing NK and CD8+ T cell function and promoting ADCC.

immunology↗

bioRxiv2021

SARS-CoV-2 vaccination induces neutralizing antibodies against pandemic and pre-emergent SARS-related coronaviruses in monkeys

Betacoronaviruses (betaCoVs) caused the severe acute respiratory syndrome (SARS) and Middle East Respiratory Syndrome (MERS) outbreaks, and now the SARS-CoV-2 pandemic. Vaccines that elicit protective immune responses against SARS-CoV-2 and betaCoVs circulating in animals have the potential to prevent future betaCoV pandemics. Here, we show that immunization of macaques with a multimeric SARS-CoV-2 receptor binding domain (RBD) nanoparticle adjuvanted with 3M-052-Alum elicited cross-neutralizing antibody responses against SARS-CoV-1, SARS-CoV-2, batCoVs and the UK B.1.1.7 SARS-CoV-2 mutant virus. Nanoparticle vaccination resulted in a SARS-CoV-2 reciprocal geometric mean neutralization titer of 47,216, and robust protection against SARS-CoV-2 in macaque upper and lower respiratory tracts. Importantly, nucleoside-modified mRNA encoding a stabilized transmembrane spike or monomeric RBD protein also induced SARS-CoV-1 and batCoV cross-neutralizing antibodies, albeit at lower titers. These results demonstrate current mRNA vaccines may provide some protection from future zoonotic betaCoV outbreaks, and provide a platform for further development of pan-betaCoV nanoparticle vaccines.

immunology↗