Loss of olfactory function has been commonly reported in severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infections. Recovery from anosmia is not well understood. Previous studies showed that sustentacular cells, and occasionally, olfactory sensory neurons (OSNs) in the olfactory epithelium (OE) are infected in SARS-CoV-2-infected patients and experimental animals. Here, we show that SARS-CoV-2 infection of sustentacular cells induces inflammation characterized by infiltration of myeloid cells to the olfactory epithelium and variably increased expression of proinflammatory cytokines. We observed widespread damage to, and loss of cilia on, OSNs, accompanied by downregulation of olfactory receptors and signal transduction molecules involved in olfaction. A consequence of OSN dysfunction was a reduction in the number of neurons in the olfactory bulb expressing tyrosine hydroxylase, consistent with reduced synaptic input. Resolution of the infection, inflammation, and olfactory dysfunction occurred over 3-4 weeks following infection in most but not all animals. We also observed similar patterns of OE infection and anosmia/hyposmia in mice infected with other human coronaviruses such as SARS-CoV and MERS-CoV. Together, these results define the downstream effects of sustentacular cell infection and provide insight into olfactory dysfunction in COVID-19-associated anosmia.
Abhishek Kumar Verma, Jian Zheng, David K. Meyerholz, Stanley Perlman
Despite the widespread use of SARS-CoV-2-specific monoclonal antibody (mAb) therapy for the treatment of acute COVID-19, the impact of this therapy on the development of SARS-CoV-2-specific T cell responses has been unknown, resulting in uncertainty as to whether anti-SARS-CoV-2 mAb administration may result in failure to generate immune memory. Alternatively, it has been suggested that SARS-CoV-2-specific mAb may enhance adaptive immunity to SARS-CoV-2 via a "vaccinal effect." Bamlanivimab (Eli Lilly) is a recombinant human IgG1 that was granted FDA emergency use authorization for the treatment of mild to moderate COVID-19 in those at high risk for progression to severe disease. Here, we compared SARS-CoV-2 specific CD4+ and CD8+ T cell responses of 95 individuals from the ACTIV-2/A5401 clinical trial 28 days after treatment with 700 mg bamlanivimab versus placebo. SARS-CoV-2-specific T cell responses were evaluated using activation induced marker (AIM) assays in conjunction with intracellular cytokine staining. We demonstrate that most individuals with acute COVID-19 develop SARS-CoV-2-specific T cell responses. Overall, our findings suggest that the quantity and quality of SARS-CoV-2-specific T cell memory was robust in individuals who received bamlanivimab for acute COVID-19. Receipt of bamlanivimab during acute COVID-19 neither diminished nor enhanced SARS-CoV-2-specific cellular immunity.
Sydney I. Ramirez, Alba Grifoni, Daniela Weiskopf, Urvi M. Parikh, Amy Heaps, Farhoud Faraji, Scott F. Sieg, Justin Ritz, Carlee B. Moser, Joseph J. Eron, Judith S. Currier, Paul Klekotka, Alessandro Sette, David A. Wohl, Eric S. Daar, Michael D. Hughes, Kara W. Chew, Davey M. Smith, Shane Crotty
Consecutive mRNA vaccinations against SARS-CoV-2 reinforced both innate and adaptive immune responses. However, it remains unclear whether the enhanced innate immune responses are mediated by epigenetic regulation and, if so, whether these effects persist. Using mass cytometry, RNA-seq, and ATAC-seq, we show that BNT162b2 mRNA vaccination upregulated antiviral and IFN-stimulated gene expression in monocytes with greater effects after the second vaccination than those after the first vaccination. Transcription factor-binding motif analysis also revealed enriched IFN regulatory factors and PU.1 motifs in accessible chromatin regions. Importantly, although consecutive BNT162b2 mRNA vaccinations boosted innate immune responses and caused epigenetic changes in isolated monocytes, we showed that these effects occur only transiently and disappear 4 weeks after the second vaccination. Furthermore, single-cell RNA sequencing analysis revealed that a similar gene signature was impaired in the monocytes of unvaccinated COVID-19 patients with acute respiratory distress syndrome. These results reinforce the importance of the innate immune response in the determination of COVID-19 severity but indicate that, unlike adaptive immunity, innate immunity is not unexpectedly sustained even after consecutive vaccination. This study, which focuses on innate immmune memory, may provide novel insights into the vaccine development against infectious diseases.
Yuta Yamaguchi, Yasuhiro Kato, Ryuya Edahiro, Jonas N. Søndergaard, Teruaki Murakami, Saori Amiya, Shinichiro Nameki, Yuko Yoshimine, Takayoshi Morita, Yusuke Takeshima, Shuhei Sakakibara, Yoko Naito, Daisuke Motooka, Yu-Chen Liu, Yuya Shirai, Yasutaka Okita, Jun Fujimoto, Haruhiko Hirata, Yoshito Takeda, James B. Wing, Daisuke Okuzaki, Yukinori Okada, Atsushi Kumanogoh
Protective immunity against SARS-CoV-2 infection after COVID-19 vaccination may differ by variant. We enrolled vaccinated (n = 39) and unvaccinated (n = 11) individuals with acute, symptomatic SARS-CoV-2 Delta or Omicron infection and performed SARS-CoV-2 viral load quantification, whole-genome sequencing, and variant-specific antibody characterization at the time of acute illness and convalescence. Viral load at the time of infection was inversely correlated with antibody binding and neutralizing antibody responses. Across all variants tested, convalescent neutralization titers in unvaccinated individuals were markedly lower than in vaccinated individuals. Increases in antibody titers and neutralizing activity occurred at convalescence in a variant-specific manner. For example, among individuals infected with the Delta variant, neutralizing antibody responses were weakest against BA.2, whereas infection with Omicron BA.1 variant generated a broader response against all tested variants, including BA.2.
Michael S. Seaman, Mark J. Siedner, Julie Boucau, Christy L. Lavine, Fadi Ghantous, May Y. Liew, Josh I. Mathews, Arshdeep Singh, Caitlin Marino, James Regan, Rockib Uddin, Manish C. Choudhary, James P. Flynn, Geoffrey Chen, Ashley M. Stuckwisch, Taryn Lipiner, Autumn Kittilson, Meghan Melberg, Rebecca F. Gilbert, Zahra Reynolds, Surabhi L. Iyer, Grace C. Chamberlin, Tammy D. Vyas, Jatin M. Vyas, Marcia B. Goldberg, Jeremy Luban, Jonathan Z. Li, Amy K. Barczak, Jacob E. Lemieux
Cross-reactive immunity between SARS-CoV-2 and other related coronaviruses has been well-documented, and it may play a role in preventing severe COVID-19. Epidemiological studies early in the pandemic showed a geographical association between high influenza vaccination rates and lower incidence of SARS-CoV-2 infection. We, therefore, analyzed whether exposure to influenza A virus (IAV) antigens could influence the T cell repertoire in response to SARS-CoV-2, indicating a heterologous immune response between these 2 unrelated viruses. Using artificial antigen-presenting cells (aAPCs) combined with real-time reverse-transcription PCR (RT-qPCR), we developed a sensitive assay to quickly screen for antigen-specific T cell responses and detected a significant correlation between responses to SARS-CoV-2 epitopes and IAV dominant epitope (M158–66). Further analysis showed that some COVID-19 convalescent donors exhibited both T cell receptor (TCR) specificity and functional cytokine responses to multiple SARS-CoV-2 epitopes and M158–66. Utilizing an aAPC-based stimulation/expansion assay, we detected cross-reactive T cells with specificity to SARS-CoV-2 and IAV. In addition, TCR sequencing of the cross-reactive and IAV-specific T cells revealed similarities between the TCR repertoires of the two populations. These results indicate that heterologous immunity shaped by our exposure to other unrelated endemic viruses may affect our immune response to novel viruses such as SARS-CoV-2.
Worarat Chaisawangwong, Hanzhi Wang, Theodore Kouo, Sebastian F. Salathe, Ariel Isser, Joan Glick Bieler, Maya L. Zhang, Natalie K. Livingston, Shuyi Li, Joseph J. Horowitz, Ron E. Samet, Israel Zyskind, Avi Z. Rosenberg, Jonathan P. Schneck
People living with HIV-1 (PLWH) exhibit more rapid antibody decline following routine immunization and elevated baseline chronic inflammation than people without HIV-1 (PWOH), indicating potential for diminished humoral immunity during SARS-CoV-2 infection. Conflicting reports have emerged on the ability of PLWH to maintain humoral protection against SARS-CoV-2 co-infection during convalescence. It is unknown if peak COVID-19 severity, along with HIV-1 infection status, associates with the quality and quantity of humoral immunity following recovery. Using a cross-sectional observational cohort from the USA and Peru, adults were enrolled 1-10 weeks post-SARS-CoV-2 infection diagnosis or symptom resolution. Serum antibodies were analyzed for SARS-CoV-2-specific response rates, binding magnitudes, ACE2 receptor blocking and antibody dependent cellular phagocytosis (ADCP). Overall, (1) PLWH exhibited a trend towards decreased magnitude of SARS-CoV-2-specific antibodies, despite modestly increased overall response rates when compared to PWOH, (2) PLWH recovered from symptomatic outpatient COVID-19 had comparatively diminished immune responses, and (3) PLWH lacked a corresponding increase in SARS-CoV-2 antibodies with increased COVID-19 severity when comparing asymptomatic to symptomatic outpatient disease.
Daniel J. Schuster, Shelly Karuna, Caroline Brackett, Martina S. Wesley, Shuying S. Li, Nathan Eisel, DeAnna Tenney, Sir'Tauria Hilliard, Nicole L. Yates, Jack R. Heptinstall, LaTonya D. Williams, Xiaoying Shen, Robert Rolfe, Robinson Cabello, Lu Zhang, Sheetal Sawant, Jiani Hu, April Kaur Randhawa, Ollivier Hyrien, John A. Hural, Lawrence Corey, Ian Frank, Georgia D. Tomaras, Kelly E. Seaton
Thick, viscous respiratory secretions are a major pathogenic feature of COVID-19, but the composition and physical properties of these secretions are poorly understood. We characterized the composition and rheological properties (i.e., resistance to flow) of respiratory secretions collected from intubated COVID-19 patients. We found the percentages of solids and protein content were greatly elevated in COVID-19 compared with heathy control samples and closely resembled levels seen in cystic fibrosis, a genetic disease known for thick, tenacious respiratory secretions. DNA and hyaluronan (HA) were major components of respiratory secretions in COVID-19 and were likewise abundant in cadaveric lung tissues from these patients. COVID-19 secretions exhibited heterogeneous rheological behaviors, with thicker samples showing increased sensitivity to DNase and hyaluronidase treatment. In histologic sections from these same patients, we observed increased accumulation of HA and the hyaladherin versican but reduced tumor necrosis factor–stimulated gene-6 staining, consistent with the inflammatory nature of these secretions. Finally, we observed diminished type I interferon and enhanced inflammatory cytokines in these secretions. Overall, our studies indicated that increases in HA and DNA in COVID-19 respiratory secretion samples correlated with enhanced inflammatory burden and suggested that DNA and HA may be viable therapeutic targets in COVID-19 infection.
Michael J. Kratochvil, Gernot Kaber, Sally Demirdjian, Pamela C. Cai, Elizabeth B. Burgener, Nadine Nagy, Graham L. Barlow, Medeea Popescu, Mark R. Nicolls, Michael G. Ozawa, Donald P. Regula, Ana E. Pacheco-Navarro, Samuel Yang, Vinicio A. de Jesus Perez, Harry Karmouty-Quintana, Andrew M. Peters, Bihong Zhao, Maximilian L. Buja, Pamela Y. Johnson, Robert B. Vernon, Thomas N. Wight, Stanford COVID-19 Biobank Study Group, Carlos E. Milla, Angela J. Rogers, Andrew J. Spakowitz, Sarah C. Heilshorn, Paul L. Bollyky
Immunosuppressed patients with inflammatory bowel disease (IBD) generate lower amounts of SARS-CoV-2 spike antibodies after mRNA vaccination than healthy controls. We assessed SARS-CoV-2 spike S1 receptor binding domain–specific (S1-RBD–specific) B lymphocytes to identify the underlying cellular defects. Patients with IBD produced fewer anti–S1-RBD antibody–secreting B cells than controls after the first mRNA vaccination and lower amounts of total and neutralizing antibodies after the second. S1-RBD–specific memory B cells were generated to the same degree in IBD and control groups and were numerically stable for 5 months. However, the memory B cells in patients with IBD had a lower S1-RBD–binding capacity than those in controls, which is indicative of a defect in antibody affinity maturation. Administration of a third shot to patients with IBD elevated serum antibodies and generated memory B cells with a normal antigen-binding capacity. These results show that patients with IBD have defects in the formation of antibody-secreting B cells and affinity-matured memory B cells that are corrected by a third vaccination.
Kathryn A. Pape, Thamotharampillai Dileepan, William E. Matchett, Charles Ellwood, Samuel Stresemann, Amanda J. Kabage, Daria Kozysa, Clayton Evert, Michael Matson, Sharon Lopez, Peter D. Krueger, Carolyn T. Graiziger, Byron P. Vaughn, Eugenia Shmidt, Joshua Rhein, Timothy W. Schacker, Tyler D. Bold, Ryan A. Langlois, Alexander Khoruts, Marc K. Jenkins
Long COVID, a type of Post-Acute Sequelae of SARS-CoV-2 (PASC), has been associated with sustained elevated levels of immune activation and inflammation. However, the mechanisms that drive this inflammation remain unknown. Inflammation during acute Coronavirus Disease 2019 could be exacerbated by microbial translocation (from gut and/or lung) to blood. Whether microbial translocation contributes to inflammation during PASC is unknown. We did not observe a significant elevation in plasma markers of bacterial translocation during PASC. However, we observed higher levels of fungal translocation – measured as β-glucan, a fungal cell wall polysaccharide – in the plasma of individuals experiencing PASC compared to those without PASC or SARS-CoV-2 negative controls. The higher β-glucan correlated with higher inflammation and elevated levels of host metabolites involved in activating N-Methyl-D-aspartate receptors (such as metabolites within the tryptophan catabolism pathway) with established neuro-toxic properties. Mechanistically, β-glucan can directly induce inflammation by binding to myeloid cells (via Dectin-1) and activating Syk/NF-κB signaling. Using a Dectin-1/NF-κB reporter model, we found that plasma from individuals experiencing PASC induced higher NF-κB signaling compared to plasma from negative controls. This higher NF-κB signaling was abrogated by Piceatannol (Syk inhibitor). These data suggest a potential targetable mechanism linking fungal translocation and inflammation during PASC.
Leila B. Giron, Michael J. Peluso, Jianyi Ding, Grace Kenny, Netanel F. Zilberstein, Jane Koshy, Kai Ying Hong, Heather Rasmussen, Gregory E. Miller, Faraz Bishehsari, Robert A. Balk, James N. Moy, Rebecca Hoh, Scott Lu, Aaron R. Goldman, Hsin-Yao Tang, Brandon C. Yee, Ahmed Chenna, John W. Winslow, Christos J. Petropoulos, J. Daniel Kelly, Haimanot Wasse, Jeffrey N. Martin, Qin Liu, Ali Keshavarzian, Alan Landay, Steven G. Deeks, Timothy J. Henrich, Mohamed Abdel-Mohsen
Vaccine-elicited SARS-CoV-2 antibody responses are an established correlate of protection against viral infection in humans and non-human primates. However, it is less clear that vaccine-induced immunity is able to limit infection-elicited inflammation in the lower respiratory tract. To assess this, we collected bronchoalveolar lavage fluid samples post-SARS-CoV-2 strain USA-WA1/2020 challenge from rhesus macaques vaccinated with mRNA-1273 in a dose-reduction study. Single-cell transcriptomic profiling revealed a broad cellular landscape 48 hours post-challenge with distinct inflammatory signatures that correlated with viral RNA burden in the lower respiratory tract. These inflammatory signatures included phagocyte-restricted expression of chemokines such as CXCL10 (IP10) and CCL3 (MIP-1A) and the broad expression of interferon-induced genes such as MX1, ISG15, and IFIT1. Induction of these inflammatory profiles was suppressed by prior mRNA-1273 vaccination in a dose-dependent manner, and negatively correlated with pre-challenge serum and lung antibody titers against SARS-CoV-2 spike. These observations were replicated and validated in a second independent macaque challenge study using the B.1.351/beta-variant of SARS-CoV-2. These data support a model wherein vaccine-elicited antibody responses restrict viral replication following SARS-CoV-2 exposure, including limiting viral dissemination to the lower respiratory tract and infection-mediated inflammation and pathogenesis.
Adam T. Waickman, Kaitlin Victor, Krista Newell, Tao Li, Heather Friberg, Kathryn E. Foulds, Mario Roederer, Diane L. Bolton, Jeffrey R. Currier, Robert Seder
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