Project description:Despite remarkable progress in the development and authorization of vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), there is a need to validate vaccine platforms for broader application. The current intramuscular vaccines are designed to elicit systemic immunity without conferring mucosal immunity in the nasal compartment, which is the first barrier that SARS-CoV-2 virus breaches before dissemination to the lung. We report the development of an intranasal subunit vaccine that uses lyophilized spike protein and liposomal STING agonist as an adjuvant. This vaccine induces systemic neutralizing antibodies, IgA in the lung and nasal compartments, and T-cell responses in the lung of mice. Single-cell RNA sequencing confirmed the coordinated activation of T/B-cell responses in a germinal center-like manner within the nasal-associated lymphoid tissues, confirming its role as an inductive site to enable durable immunity. The ability to elicit immunity in the respiratory tract can prevent the establishment of infection in individuals and prevent disease transmission.
Project description:Vaccination against tuberculosis by intradermal Bacillus Calmette-Guérin (BCG) injection saves many lives, supposedly by inducing adaptive immune memory in lymphocytes. Epidemiologically, BCG vaccination is also associated with reduced childhood mortality unrelated to TB, which is attributed to innate immune memory, also termed trained immunity. We recently demonstrated improved protection against tuberculosis infection in highly susceptible rhesus macaques by mucosal BCG vaccination, correlating with a unique local but no peripheral immune profile. Here, we investigated local and peripheral innate immune function after intradermal versus mucosal vaccination with M. bovis BCG or the live attenuated, M. tuberculosis-derived candidate, MTBVAC. The results demonstrate an augmented frequency of trained immunity in monocytes after respiratory mucosal administration of live attenuated mycobacterial vaccines compared to intradermal immunization, with MTBVAC being equally potent as BCG. These results provide further support to strategies for improving TB vaccination and, more broadly, modulating innate immunity via mucosal surfaces.
Project description:Respiratory tract vaccination has an advantage of needle-free delivery and induction of mucosal immune response in the portal of SARS-CoV-2 entry. We utilized human parainfluenza virus type 3 vector to generate constructs expressing the full spike (S) protein of SARS-CoV-2, its S1 subunit, or the receptor-binding domain, and tested them in hamsters as single-dose intranasal vaccines. The construct bearing full-length S induced high titers of neutralizing antibodies specific to S protein domains critical to the protein functions. Robust tissue-resident T cell responses in the lungs were also induced, which represent an additional barrier to infection and should be less sensitive than the antibody responses to mutations present in SARS-CoV-2 variants. Following SARS-CoV-2 challenge, animals were protected from the disease and detectable viral replication. Vaccination prevented induction of gene pathways associated with inflammation. These results indicate advantages of respiratory vaccination against COVID-19 and inform the design of mucosal SARS-CoV-2 vaccines.
Project description:Intranasal vaccines can prime or recruit to the respiratory epithelium mucosal immune cells capable of preventing transmission of SARS-CoV-2. We found that a single intranasal dose of serotype 5-based adenoviral vectors expressing either the receptor binding domain (Ad5-RBD) or the complete ectodomain (Ad5-S) of the SARS-CoV-2 spike protein was effective in inducing i) secretory and serum anti-spike IgA and IgG, ii) robust SARS-CoV-2-neutralizing activity in the serum and in respiratory secretions, iii) rigorous spike-directed T helper 1 cell/cytotoxic T cell immunity, and iv) protection of wild-type mice from a challenge with the SARS-CoV-2 beta variant. Our data confirm and extend previous studies reporting promising preclinical results on vector-based intranasal SARS-CoV-2 vaccination, and support the potential of this approach to elicit mucosal immunity for preventing reinfection and transmission of SARS-CoV-2 more effectively than the currently available vaccines.
Project description:A Single Intranasal Vaccination with a Rationally Attenuated SARS-CoV-2 Elicits Strong Humoral Immune Response and Is Protective in Syrian Hamsters
Project description:Systemic vaccination with the attenuated virus SIVmac239-∆Nef provides sterilizing or partial protection to rhesus monkeys challenged with WT SIV strains, providing important opportunities to study key immunological components of a protective host response. Here we show that intravenous vaccination with SIVmac239-∆Nef provides two potentially crucial immunological barriers localized at mucosal surfaces that correlate with the vaccine’s protective effects against WT SIVmac251 vaginal challenge: 1) a conditioned and coordinated response from the mucosal epithelium that blunts the early inflammatory and chemotactic signalling cascade that aids virus propagation and expansion; 2) early on-site generation/diversification of SIV-specific Abs from ectopic germinal center-like lymphoid aggregates. This unique host response to WT SIVmac251 in the female reproductive tract of SIVmac239-∆Nef-vaccinated animals points to a multi-layered strategy for a protective host response during immunodeficiency virus exposure—rapid induction of humroal immunity at mucosal surfaces without the deleterious inflammatory side effects tied to innate recognition of virus. This vaccine-induced host response highlights potential key protective mechanisms needed for an effective HIV vaccine
Project description:Systemic vaccination with the attenuated virus SIVmac239-∆Nef provides sterilizing or partial protection to rhesus monkeys challenged with WT SIV strains, providing important opportunities to study key immunological components of a protective host response. Here we show that intravenous vaccination with SIVmac239-∆Nef provides two potentially crucial immunological barriers localized at mucosal surfaces that correlate with the vaccine’s protective effects against WT SIVmac251 vaginal challenge: 1) a conditioned and coordinated response from the mucosal epithelium that blunts the early inflammatory and chemotactic signalling cascade that aids virus propagation and expansion; 2) early on-site generation/diversification of SIV-specific Abs from ectopic germinal center-like lymphoid aggregates. This unique host response to WT SIVmac251 in the female reproductive tract of SIVmac239-∆Nef-vaccinated animals points to a multi-layered strategy for a protective host response during immunodeficiency virus exposure—rapid induction of humroal immunity at mucosal surfaces without the deleterious inflammatory side effects tied to innate recognition of virus. This vaccine-induced host response highlights potential key protective mechanisms needed for an effective HIV vaccine Total RNA was isolated from the cervix of 17 Indian Rhesus macaques (3 uninfected animals; 5 unvaccinated animals 4-5 days post vaginal exposure with SIVmac251; 4 SIVmac239-∆Nef-vaccinated animals before challenge; 5 SIVmac239-∆Nef-vaccinated animals 4-5 days post vaginal exposure with SIVmac251) and prepared for hybridization on Affymetrix GeneChip Rhesus Macaque Genome Arrays. Replicate arrays were performed for a number of the samples to minimize assay noise and significant host genes altered during virus exposure in female reproductive tract tissue were identified by their associated q-values (< 0.2) and fold change in expression (> 1.2).
Project description:The coronavirus disease 2019 (COVID-19) pandemic has highlighted the urgent need for effective prophylactic vaccination to prevent the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Intranasal vaccination is an attractive strategy to prevent COVID-19 as the nasal mucosa represents the first-line barrier to SARS-CoV-2 entry. The current intramuscular vaccines elicit systemic immunity but not necessarily high-level mucosal immunity. Here, we tested a single intranasal dose of our candidate adenovirus type 5-vectored vaccine encoding the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein (AdCOVID) in inbred, outbred, and transgenic mice. A single intranasal vaccination with AdCOVID elicited a strong and focused immune response against RBD through the induction of mucosal IgA in the respiratory tract, serum neutralizing antibodies, and CD4+ and CD8+ T cells with a Th1-like cytokine expression profile. A single AdCOVID dose resulted in immunity that was sustained for over six months. Moreover, a single intranasal dose completely protected K18-hACE2 mice from lethal SARS-CoV-2 challenge, preventing weight loss and mortality. These data show that AdCOVID promotes concomitant systemic and mucosal immunity and represents a promising vaccine candidate.