Browsing by Author "Li, Chunfeng"

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    A TLR7-nanoparticle adjuvant promotes a broad immune response against heterologous strains of influenza and SARS-CoV-2
    (Springer Nature, 2023) Yin, Qian; Luo, Wei; Mallajosyula, Vamsee; Bo, Yang; Guo, Jing; Xie, Jinghang; Sun, Meng; Verma, Rohit; Li, Chunfeng; Constantz, Christian M.; Wagar, Lisa E.; Li, Jing; Sola, Elsa; Gupta, Neha; Wang, Chunlin; Kask, Oliver; Chen, Xin; Yuan, Xue; Wu, Nicholas C.; Rao, Jianghong; Chien, Yueh-hsiu; Cheng, Jianjun; Pulendran, Bali; Davis, Mark M.; Microbiology and Immunology, School of Medicine
    The ideal vaccine against viruses such as influenza and SARS-CoV-2 must provide a robust, durable and broad immune protection against multiple viral variants. However, antibody responses to current vaccines often lack robust cross-reactivity. Here we describe a polymeric Toll-like receptor 7 agonist nanoparticle (TLR7-NP) adjuvant, which enhances lymph node targeting, and leads to persistent activation of immune cells and broad immune responses. When mixed with alum-adsorbed antigens, this TLR7-NP adjuvant elicits cross-reactive antibodies for both dominant and subdominant epitopes and antigen-specific CD8+ T-cell responses in mice. This TLR7-NP-adjuvanted influenza subunit vaccine successfully protects mice against viral challenge of a different strain. This strategy also enhances the antibody response to a SARS-CoV-2 subunit vaccine against multiple viral variants that have emerged. Moreover, this TLR7-NP augments antigen-specific responses in human tonsil organoids. Overall, we describe a nanoparticle adjuvant to improve immune responses to viral antigens, with promising implications for developing broadly protective vaccines.
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    Mechanisms of innate and adaptive immunity to the Pfizer-BioNTech BNT162b2 vaccine
    (Springer Nature, 2022) Li, Chunfeng; Lee, Audrey; Grigoryan, Lilit; Arunachalam, Prabhu S.; Scott, Madeleine K.D.; Trisal, Meera; Wimmers, Florian; Sanyal, Mrinmoy; Weidenbacher, Payton A.; Feng, Yupeng; Adamska, Julia Z.; Valore, Erika; Wang, Yanli; Verma, Rohit; Reis, Noah; Dunham, Diane; O’Hara, Ruth; Park, Helen; Luo, Wei; Gitlin, Alexander D.; Kim, Peter; Khatri, Purvesh; Nadeau, Kari C.; Pulendran, Bali; Microbiology and Immunology, School of Medicine
    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)-γ levels 1 d 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-γ. 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.
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    SREBP signaling is essential for effective B cell responses
    (Springer Nature, 2023) Luo, Wei; Adamska, Julia Z.; Li, Chunfeng; Verma, Rohit; Liu, Qing; Hagan, Thomas; Wimmers, Florian; Gupta, Shakti; Feng, Yupeng; Jiang, Wenxia; Zhou, Jiehao; Valore, Erika; Wang, Yanli; Trisal, Meera; Subramaniam, Shankar; Osborne, Timothy F.; Pulendran, Bali; Microbiology and Immunology, School of Medicine
    Our previous study using systems vaccinology identified an association between the sterol regulatory binding protein (SREBP) pathway and humoral immune response to vaccination in humans. To investigate the role of SREBP signaling in modulating immune responses, we generated mice with B cell- or CD11c+ antigen-presenting cell (APC)-specific deletion of SCAP, an essential regulator of SREBP signaling. Ablation of SCAP in CD11c+ APCs had no effect on immune responses. In contrast, SREBP signaling in B cells was critical for antibody responses, as well as the generation of germinal centers,memory B cells and bone marrow plasma cells. SREBP signaling was required for metabolic reprogramming in activated B cells. Upon mitogen stimulation, SCAP-deficient B cells could not proliferate and had decreased lipid rafts. Deletion of SCAP in germinal center B cells using AID-Cre decreased lipid raft content and cell cycle progression. These studies provide mechanistic insights coupling sterol metabolism with the quality and longevity of humoral immunity.