key: cord-0882139-lxkbxfmm authors: Vesin, Benjamin; Lopez, Jodie; Noirat, Amandine; Authié, Pierre; Fert, Ingrid; Le Chevalier, Fabien; Moncoq, Fanny; Nemirov, Kirill; Blanc, Catherine; Planchais, Cyril; Mouquet, Hugo; Guinet, Françoise; Hardy, David; Gerke, Christiane; Anna, François; Bourgine, Maryline; Majiessi, Laleh; Charneau, Pierre title: An intranasal lentiviral booster broadens immune recognition of SARS-CoV-2 variants and reinforces the waning mRNA vaccine-induced immunity that it targets to lung mucosa date: 2022-01-31 journal: bioRxiv DOI: 10.1101/2022.01.30.478159 sha: a8dc056c9d629c7e4e492819dcff1a79437b8c62 doc_id: 882139 cord_uid: lxkbxfmm As the COVID-19 pandemic continues and new SARS-CoV-2 variants of concern emerge, the adaptive immunity initially induced by the first-generation COVID-19 vaccines wains and needs to be strengthened and broadened in specificity. Vaccination by the nasal route induces mucosal humoral and cellular immunity at the entry point of SARS-CoV-2 into the host organism and has been shown to be the most effective for reducing viral transmission. The lentiviral vaccination vector (LV) is particularly suitable for this route of immunization because it is non-cytopathic, non-replicative and scarcely inflammatory. Here, to set up an optimized cross-protective intranasal booster against COVID-19, we generated an LV encoding stabilized Spike of SARS-CoV-2 Beta variant (LV::SBeta-2P). mRNA vaccine–primed and -boosted mice, with waning primary humoral immunity at 4 months post-vaccination, were boosted intranasally with LV::SBeta-2P. Strong boost effect was detected on cross-sero-neutralizing activity and systemic T-cell immunity. In addition, mucosal anti-Spike IgG and IgA, lung resident B cells, and effector memory and resident T cells were efficiently induced, correlating with complete pulmonary protection against the SARS-CoV-2 Delta variant, demonstrating the suitability of the LV::SBeta-2P vaccine candidate as an intranasal booster against COVID-19. human Angiotensin Converting Enzyme 2 (hACE2) and displaying unprecedented permissiveness 56 of the brain to SARS-CoV-2 replication, an i.n. boost with LV::S is required for full protection of 57 the central nervous system [3] . LV::S is intended to be used as a booster for individuals who 58 previously been vaccinated against and/or infected by SARS-CoV-2 to reinforce and broaden 59 protection against emerging VOCs with immune evasion potential [4] . 60 Vaccine LVs are non-integrating, non-replicative, non-cytopathic and negligibly inflammatory 61 [5, 6] . These vectors are pseudotyped with the heterologous glycoprotein from Vesicular Stomatitis 62 Virus (VSV-G) which confers them a broad tropism for diverse cell types, including dendritic cells. 63 The latter are mainly non-dividing cells and thus barely permissive to gene transfer. Hence, LVs 64 possess the central property to efficiently transfer genes to the nuclei of not only dividing but also 65 non-dividing cells, which therefore renders possible efficient transduction of non-dividing immature 66 dendritic cells. The resulting endogenous antigen expression in these cells, with unique ability of 67 dendritic cells to activate naïve T cells [7] , correlate with a strong ability of LVs at inducing high-68 quality effector and memory T cells [8] . Importantly, VSV-G pseudo-typing also avoids LVs to be 69 targets of preexisting vector-specific immunity in humans which is key in vaccine development 70 [5, 6] . The safety of LV has been established in humans in a phase I/IIa Human Immunodeficiency 71 Virus-1 therapeutic vaccine trial, even though if an integrative version of LV had been used in that 72 clinical trial [9] . Because of their non-cytopathic and non-inflammatory properties [10, 11] , LVs are 73 well suitable for mucosal vaccination. The i.n. immunization approach is expected to trigger 74 mucosal IgA responses, as well as resident B and T lymphocytes in the respiratory tract [12] . This 75 immunization route has also been shown to be the most effective at reducing SARS-CoV-2 76 transmission in both hamster and macaque preclinical models [13] . Induction of mucosal immunity 77 by i.n. immunization allows SARS-CoV-2 neutralization, directly at the gateway to the host 78 organism, before it gains access to major infectable anatomical sites [2] . 79 of their sera was assessed before boost (wk 3) and after boost (wk 5) against pseudoviruses 111 carrying various S CoV-2 ( Figure 1A) . Immunization with LV::S Alpha generated appropriate 112 neutralization capacity against S D614G and S Alpha but not against S Beta and S Gamma ( Figure 1B) . 113 Between LV::S Beta and LV::S Gamma , the former generated the highest cross sero-neutralization 114 potential against S D614G , S Alpha and S Gamma variants. In accordance with previous observations using 115 other vaccination strategies, in the context of immunization with LV, the K 986 P -V 987 P 116 substitutions in the S2 domain of S CoV-2 improved the (cross) sero-neutralization potential ( Figure 117 1C), probably due to an extended half-life of S CoV-2-2P [20] . 118 Taken together these data allowed to down select S Beta-2P as the best cross-reactive antigen 119 candidate to be used in the context of LV (LV::S Beta-2P ) to strengthen the waning immunity 120 previously induced by the first generation COVID-19 vaccines, like mRNA. We analyzed the potential of LV::S Beta-2P i.n. boost vaccination to strengthen and broaden the 125 immune responses in mice which were initially primed and boosted with mRNA and in which the 126 (cross) sero-neutralization potential was decreasing. C57BL/6 mice were primed i.m. at wk 0 and 127 boosted i.m. at wk 3 with 1 µg/mouse of mRNA (Figure 2A) . In mRNA-primed mice, serum anti-128 S CoV-2 and anti-RBD IgG were detected at wk 3, increased after mRNA boost as studied at wk 6 129 and 10, and then decreased at wk 17 in the absence of an additional boost ( Figure S1A) . 130 Longitudinal serological follow-up demonstrated that at 3 wks post prime, cross-neutralization 131 activities against both S D614G and S Alpha were readily detectable ( Figure 2B ). Cross sero-132 neutralization was also detectable, although to a lesser degree, against S Gamma , but not against 133 S Beta , S Delta or S Delta+ . At wk 6, i.e., 3 wks post boost, cross sero-neutralization activities against all 134 S CoV-2 variants were detectable, although at significantly lesser extents against S Beta , S Delta and 135 S Delta+ . From wk 6 to wk 10, cross sero-neutralization against S Beta , S Delta , or S Delta+ gradually and 136 In the previously mRNA-primed and -boosted mice, injected at wk 15 with 1 × 10 8 or 1 × 10 9 146 TU of LV::S Beta-2P or a third dose of mRNA, marked anti-S CoV-2 IgG titer increases were observed 147 The LV-based strategy, which is highly efficient, not only in inducing humoral responses but 240 also, and particularly, in establishing high quality and memory T-cell responses [8], is a favorable 241 platform for a heterologous boost, even if it is also largely efficacious by its own as a primary 242 COVID-19 vaccine candidate [2,3]. Furthermore, LV is non-cytopathic, non-replicative and 243 scarcely inflammatory and thus can be used to perform non-invasive i.n. boost to efficiently induce 244 sterilizing mucosal immunity, which protects the respiratory system as well as the central nervous Tolerability and Immunogenicity Induced by the THV01 Treatment in 421 Patients Infected With HIV-1 Clade B and Treated With Highly Active Antiretroviral Therapy (HAART) Persistence of Integrase-Deficient Lentiviral Vectors Correlates with 424 the Induction of STING-Independent CD8(+) T Cell Responses An optimized lentiviral vector induces CD4+ T-cell immunity and predicts a 426 booster vaccine against tuberculosis Scent of a vaccine Intranasal ChAdOx1 nCoV-19/AZD1222 vaccination 429 reduces viral shedding after SARS-CoV-2 D614G challenge in preclinical models Maintaining Safety with SARS-CoV-2 Vaccines Heterologous prime-boost: breaking the protective immune response bottleneck of 434 COVID-19 vaccine candidates Heterologous prime-boost vaccination Effectiveness of heterologous ChAdOx1 nCoV-19 and mRNA prime-437 boost vaccination against symptomatic Covid-19 infection in Sweden: A nationwide cohort study An mRNA Vaccine against SARS-CoV-2 -Preliminary Report An Evidence Based Perspective on mRNA-SARS-CoV-2 Vaccine 442 Structure, Function, and Antigenicity of 444 the SARS-CoV-2 Spike Glycoprotein SARS-CoV-2 mRNA vaccine design enabled by prototype pathogen 446 preparedness Lung-resident memory B cells protect against bacterial pneumonia Memory B cells in the lung participate in protective humoral immune 450 responses to pulmonary influenza virus reinfection Tissue-Resident T Cells and Other Resident Leukocytes SARS-CoV-2 infection protects against rechallenge in rhesus 454 macaques Ad26 vaccine protects against SARS-CoV-2 severe clinical 456 disease in hamsters Virological assessment of hospitalized patients with COVID-458 2019 Immune responses against SARS-CoV-2 variants 460 after heterologous and homologous ChAdOx1 nCoV-19/BNT162b2 vaccination Prime-boost vaccine strategy against viral infections: Mechanisms and 463 benefits Adaptive immunity to SARS-CoV-2 and COVID-19