All Publications


  • Chemically Modified Bacterial Sacculi as a Vaccine Microparticle Scaffold. ACS chemical biology Weidenbacher, P. A., Rodriguez-Rivera, F. P., Sanyal, M., Visser, J. A., Do, J., Bertozzi, C. R., Kim, P. S. 2022

    Abstract

    Vaccine scaffolds and carrier proteins increase the immunogenicity of subunit vaccines. Here, we developed, characterized, and demonstrated the efficacy of a novel microparticle vaccine scaffold comprised of bacterial peptidoglycan (PGN), isolated as an entire sacculi. The PGN microparticles contain bio-orthogonal chemical handles allowing for site-specific attachment of immunogens. We first evaluated the purification, integrity, and immunogenicity of PGN microparticles derived from a variety of bacterial species. We then optimized PGN microparticle modification conditions; Staphylococcus aureus PGN microparticles containing azido-d-alanine yielded robust conjugation to immunogens. We then demonstrated that this vaccine scaffold elicits comparable immunostimulation to the conventional carrier protein, keyhole limpet hemocyanin (KLH). We further modified the S. aureus PGN microparticle to contain the SARS-CoV-2 receptor-binding domain (RBD)─this conjugate vaccine elicited neutralizing antibody titers comparable to those elicited by the KLH-conjugated RBD. Collectively, these findings suggest that chemically modified bacterial PGN microparticles are a conjugatable and biodegradable microparticle scaffold capable of eliciting a robust immune response toward an antigen of interest.

    View details for DOI 10.1021/acschembio.2c00140

    View details for PubMedID 35412807

  • Mechanisms of innate and adaptive immunity to the Pfizer-BioNTech BNT162b2 vaccine. Nature immunology Li, C., Lee, A., Grigoryan, L., Arunachalam, P. S., Scott, M. K., Trisal, M., Wimmers, F., Sanyal, M., Weidenbacher, P. A., Feng, Y., Adamska, J. Z., Valore, E., Wang, Y., Verma, R., Reis, N., Dunham, D., O'Hara, R., Park, H., Luo, W., Gitlin, A. D., Kim, P., Khatri, P., Nadeau, K. C., Pulendran, B. 2022

    Abstract

    Despite the success of the BNT162b2 mRNA vaccine, the immunological mechanisms that underlie its efficacy are poorly understood. Here we analyzed the innate and adaptive responses to BNT162b2 in mice, and show that immunization stimulated potent antibody and antigen-specific T cell responses, as well as strikingly enhanced innate responses after secondary immunization, which was concurrent with enhanced serum interferon (IFN)-gamma levels 1d following secondary immunization. Notably, we found that natural killer cells and CD8+ T cells in the draining lymph nodes are the major producers of this circulating IFN-gamma. Analysis of knockout mice revealed that induction of antibody and T cell responses to BNT162b2 was not dependent on signaling via Toll-like receptors 2, 3, 4, 5 and 7 nor inflammasome activation, nor the necroptosis or pyroptosis cell death pathways. Rather, the CD8+ T cell response induced by BNT162b2 was dependent on type I interferon-dependent MDA5 signaling. These results provide insights into the molecular mechanisms by which the BNT162b2 vaccine stimulates immune responses.

    View details for DOI 10.1038/s41590-022-01163-9

    View details for PubMedID 35288714

  • Protect, modify, deprotect (PMD): A strategy for creating vaccines to elicit antibodies targeting a specific epitope Weidenbacher, P., Kim, P. WILEY. 2021: 143
  • New-onset IgG autoantibodies in hospitalized patients with COVID-19. Nature communications Chang, S. E., Feng, A., Meng, W., Apostolidis, S. A., Mack, E., Artandi, M., Barman, L., Bennett, K., Chakraborty, S., Chang, I., Cheung, P., Chinthrajah, S., Dhingra, S., Do, E., Finck, A., Gaano, A., GeSSner, R., Giannini, H. M., Gonzalez, J., Greib, S., Gundisch, M., Hsu, A. R., Kuo, A., Manohar, M., Mao, R., Neeli, I., Neubauer, A., Oniyide, O., Powell, A. E., Puri, R., Renz, H., Schapiro, J., Weidenbacher, P. A., Wittman, R., Ahuja, N., Chung, H., Jagannathan, P., James, J. A., Kim, P. S., Meyer, N. J., Nadeau, K. C., Radic, M., Robinson, W. H., Singh, U., Wang, T. T., Wherry, E. J., Skevaki, C., Luning Prak, E. T., Utz, P. J. 2021; 12 (1): 5417

    Abstract

    COVID-19 is associated with a wide range of clinical manifestations, including autoimmune features and autoantibody production. Here we develop three protein arrays to measure IgG autoantibodies associated with connective tissue diseases, anti-cytokine antibodies, and anti-viral antibody responses in serum from 147 hospitalized COVID-19 patients. Autoantibodies are identified in approximately 50% of patients but in less than 15% of healthy controls. When present, autoantibodies largely target autoantigens associated with rare disorders such as myositis, systemic sclerosis and overlap syndromes. A subset of autoantibodies targeting traditional autoantigens or cytokines develop de novo following SARS-CoV-2 infection. Autoantibodies track with longitudinal development of IgG antibodies recognizing SARS-CoV-2 structural proteins and a subset of non-structural proteins, but not proteins from influenza, seasonal coronaviruses or other pathogenic viruses. We conclude that SARS-CoV-2 causes development of new-onset IgG autoantibodies in a significant proportion of hospitalized COVID-19 patients and are positively correlated with immune responses to SARS-CoV-2 proteins.

    View details for DOI 10.1038/s41467-021-25509-3

    View details for PubMedID 34521836

  • New-Onset IgG Autoantibodies in Hospitalized Patients with COVID-19 Chang, S., Feng, A., Meng, W., Apostolidis, S., Mack, E., Artandi, M., Barman, L., Bennett, K., Chakraborty, S., Chang, I., Cheung, P., Chinthrajah, S., Dhingra, S., Do, E., Finck, A., Gaano, A., Gessner, R., Giannini, H., Gonzalez, J., Greib, S., Gundisch, M., Hsu, A., Kuo, A., Manohar, M., Mao, R., Neeli, I., Neubauer, A., Oniyide, O., Powell, A., Puri, R., Renz, H., Schapiro, J., Weidenbacher, P., Wittman, R., Ahuja, N., Chung, H., Jagannathan, P., James, J., Kim, P., Meyer, N., Nadeau, K., Radic, M., Robinson, W., Singh, U., Wang, T., Wherry, J., Skevaki, C., Prak, E., Utz, P. WILEY. 2021: 3202-3205
  • A Single Immunization with Spike-Functionalized Ferritin Vaccines Elicits Neutralizing Antibody Responses against SARS-CoV-2 in Mice. ACS central science Powell, A. E., Zhang, K., Sanyal, M., Tang, S., Weidenbacher, P. A., Li, S., Pham, T. D., Pak, J. E., Chiu, W., Kim, P. S. 2021; 7 (1): 183–99

    Abstract

    The development of a safe and effective SARS-CoV-2 vaccine is a public health priority. We designed subunit vaccine candidates using self-assembling ferritin nanoparticles displaying one of two multimerized SARS-CoV-2 spikes: full-length ectodomain (S-Fer) or a C-terminal 70 amino-acid deletion (SDeltaC-Fer). Ferritin is an attractive nanoparticle platform for production of vaccines, and ferritin-based vaccines have been investigated in humans in two separate clinical trials. We confirmed proper folding and antigenicity of spike on the surface of ferritin by cryo-EM and binding to conformation-specific monoclonal antibodies. After a single immunization of mice with either of the two spike ferritin particles, a lentiviral SARS-CoV-2 pseudovirus assay revealed mean neutralizing antibody titers at least 2-fold greater than those in convalescent plasma from COVID-19 patients. Additionally, a single dose of SDeltaC-Fer elicited significantly higher neutralizing responses as compared to immunization with the spike receptor binding domain (RBD) monomer or spike ectodomain trimer alone. After a second dose, mice immunized with SDeltaC-Fer exhibited higher neutralizing titers than all other groups. Taken together, these results demonstrate that multivalent presentation of SARS-CoV-2 spike on ferritin can notably enhance elicitation of neutralizing antibodies, thus constituting a viable strategy for single-dose vaccination against COVID-19.

    View details for DOI 10.1021/acscentsci.0c01405

    View details for PubMedID 33527087

  • Targeted glycan degradation potentiates the anticancer immune response in vivo. Nature chemical biology Gray, M. A., Stanczak, M. A., Mantuano, N. R., Xiao, H., Pijnenborg, J. F., Malaker, S. A., Miller, C. L., Weidenbacher, P. A., Tanzo, J. T., Ahn, G., Woods, E. C., Laubli, H., Bertozzi, C. R. 2020

    Abstract

    Currently approved immune checkpoint inhibitor therapies targeting the PD-1 and CTLA-4 receptor pathways are powerful treatment options for certain cancers; however, most patients across cancer types still fail to respond. Consequently, there is interest in discovering and blocking alternative pathways that mediate immune suppression. One such mechanism is an upregulation of sialoglycans in malignancy, which has been recently shown to inhibit immune cell activation through multiple mechanisms and therefore represents a targetable glycoimmune checkpoint. Since these glycans are not canonically druggable, we designed an alphaHER2 antibody-sialidase conjugate that potently and selectively strips diverse sialoglycans from breast cancer cells. In syngeneic breast cancer models, desialylation enhanced immune cell infiltration and activation and prolonged the survival of mice, an effect that was dependent on expression of the Siglec-E checkpoint receptor found on tumor-infiltrating myeloid cells. Thus, antibody-sialidase conjugates represent a promising modality for glycoimmune checkpoint therapy.

    View details for DOI 10.1038/s41589-020-0622-x

    View details for PubMedID 32807964

  • A single immunization with spike-functionalized ferritin vaccines elicits neutralizing antibody responses against SARS-CoV-2 in mice. bioRxiv : the preprint server for biology Powell, A. E., Zhang, K. n., Sanyal, M. n., Tang, S. n., Weidenbacher, P. A., Li, S. n., Pham, T. D., Pak, J. E., Chiu, W. n., Kim, P. S. 2020

    Abstract

    Development of a safe and effective SARS-CoV-2 vaccine is a public health priority. We designed subunit vaccine candidates using self-assembling ferritin nanoparticles displaying one of two multimerized SARS-CoV-2 spikes: full-length ectodomain (S-Fer) or a C-terminal 70 amino-acid deletion (SΔC-Fer). Ferritin is an attractive nanoparticle platform for production of vaccines and ferritin-based vaccines have been investigated in humans in two separate clinical trials. We confirmed proper folding and antigenicity of spike on the surface of ferritin by cryo-EM and binding to conformation-specific monoclonal antibodies. After a single immunization of mice with either of the two spike ferritin particles, a lentiviral SARS-CoV-2 pseudovirus assay revealed mean neutralizing antibody titers at least 2-fold greater than those in convalescent plasma from COVID-19 patients. Additionally, a single dose of SΔC-Fer elicited significantly higher neutralizing responses as compared to immunization with the spike receptor binding domain (RBD) monomer or spike ectodomain trimer alone. After a second dose, mice immunized with SΔC-Fer exhibited higher neutralizing titers than all other groups. Taken together, these results demonstrate that multivalent presentation of SARS-CoV-2 spike on ferritin can notably enhance elicitation of neutralizing antibodies, thus constituting a viable strategy for single-dose vaccination against COVID-19.

    View details for DOI 10.1101/2020.08.28.272518

    View details for PubMedID 32869030

    View details for PubMedCentralID PMC7457616

  • Protect, modify, deprotect (PMD): A strategy for creating vaccines to elicit antibodies targeting a specific epitope PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Weidenbacher, P. A., Kim, P. S. 2019; 116 (20): 9947–52
  • Protect, modify, deprotect (PMD): A strategy for creating vaccines to elicit antibodies targeting a specific epitope. Proceedings of the National Academy of Sciences of the United States of America Weidenbacher, P. A., Kim, P. S. 2019

    Abstract

    In creating vaccines against infectious agents, there is often a desire to direct an immune response toward a particular conformational epitope on an antigen. We present a method, called protect, modify, deprotect (PMD), to generate immunogenic proteins aimed to direct a vaccine-induced antibody (Ab) response toward an epitope defined by a specific monoclonal Ab (mAb). The mAb is used to protect the target epitope on the protein. Then the remaining exposed surfaces of the protein are modified to render them nonimmunogenic. Finally, the epitope is deprotected by removal of the mAb. The resultant protein is modified at surfaces other than the target epitope. We validate PMD using a well-characterized antigen, hen egg white lysozyme, then demonstrate the utility of PMD using influenza virus hemagglutinin (HA). We use an mAb to protect a highly conserved epitope on the stem domain of HA. Exposed surface amines are then modified with short polyethylene glycol chains. The resultant antigen shows markedly reduced binding to mAbs that target the head region of HA, while maintaining binding to mAbs at the epitope of interest. This antigenic preference is also observed with yeast cells displaying Ab fragments. Antisera from guinea pigs immunized with the PMD-modified HA show increased cross-reactivity with HAs from other influenza strains, compared with antisera obtained with unmodified HA trimers. PMD has the potential to direct an Ab response at high resolution and could be used in combination with other such strategies. There are many attractive targets for the application of PMD.

    View details for PubMedID 31028143