Th17/Treg Imbalance in Murine Cystic Fibrosis Is Linked to Indoleamine 2,3-Dioxygenase Deficiency but Corrected by Kynurenines

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Hypoxia Promotes Danger-mediated Inflammation via Receptor for Advanced Glycation End Products in Cystic Fibrosis

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TLR3 essentially promotes protective class I–restricted memory CD8+ T-cell responses to Aspergillus fumigatus in hematopoietic transplanted patients

Aspergillus fumigatus is a model fungal pathogen and a common cause of severe infections and diseases. CD8+ T cells are present in the human and murine T-cell repertoire to the fungus. However, CD8+ T-cell function in infection and the molecular mechanisms that control their priming and differentiation into effector and memory cells in vivo remain elusive. In the present study, we report that both CD4+ and CD8+ T cells mediate protective memory responses to the fungus contingent on the nature of the fungal vaccine. Mechanistically, class I MHC-restricted, CD8+ memory T cells were activated through TLR3 sensing of fungal RNA by cross-presenting dendritic cells. Genetic deficiency of TLR3 was associated with susceptibility to aspergillosis and concomitant failure to activate memory-protective CD8+ T cells both in mice and in patients receiving stem-cell transplantations. Therefore, TLR3 essentially promotes antifungal memory CD8+ T-cell responses and its deficiency is a novel susceptibility factor for aspergillosis in high-risk patients.These studies were supported by the Specific Targeted Research Project ALLFUN (FP7-HEALTH-2009 contract number 260338 to L.R.), by SYBARIS (FP7-HEALTH-2009 contract number 242220 to L.R.), and by the Italian Project AIDS 2010 by the Istituto Superiore di Sanita (contract number 40H40 to L.R.). A.C. and C.C. were supported by fellowships from Fundacao para a Ciencia e Tecnologia, Portugal (contracts SFRH/BPD/46292/2008 and SFRH/BD/65962/2009, respectively)

Safety, immunogenicity, and reactogenicity of BNT162b2 and mRNA-1273 COVID-19 vaccines given as fourth-dose boosters following two doses of ChAdOx1 nCoV-19 or BNT162b2 and a third dose of BNT162b2 (COV-BOOST): a multicentre, blinded, phase 2, randomised trial

Background Some high-income countries have deployed fourth doses of COVID-19 vaccines, but the clinical need, effectiveness, timing, and dose of a fourth dose remain uncertain. We aimed to investigate the safety, reactogenicity, and immunogenicity of fourth-dose boosters against COVID-19.Methods The COV-BOOST trial is a multicentre, blinded, phase 2, randomised controlled trial of seven COVID-19 vaccines given as third-dose boosters at 18 sites in the UK. This sub-study enrolled participants who had received BNT162b2 (Pfizer-BioNTech) as their third dose in COV-BOOST and randomly assigned them (1:1) to receive a fourth dose of either BNT162b2 (30 µg in 0·30 mL; full dose) or mRNA-1273 (Moderna; 50 µg in 0·25 mL; half dose) via intramuscular injection into the upper arm. The computer-generated randomisation list was created by the study statisticians with random block sizes of two or four. Participants and all study staff not delivering the vaccines were masked to treatment allocation. The coprimary outcomes were safety and reactogenicity, and immunogenicity (antispike protein IgG titres by ELISA and cellular immune response by ELISpot). We compared immunogenicity at 28 days after the third dose versus 14 days after the fourth dose and at day 0 versus day 14 relative to the fourth dose. Safety and reactogenicity were assessed in the per-protocol population, which comprised all participants who received a fourth-dose booster regardless of their SARS-CoV-2 serostatus. Immunogenicity was primarily analysed in a modified intention-to-treat population comprising seronegative participants who had received a fourth-dose booster and had available endpoint data. This trial is registered with ISRCTN, 73765130, and is ongoing.Findings Between Jan 11 and Jan 25, 2022, 166 participants were screened, randomly assigned, and received either full-dose BNT162b2 (n=83) or half-dose mRNA-1273 (n=83) as a fourth dose. The median age of these participants was 70·1 years (IQR 51·6–77·5) and 86 (52%) of 166 participants were female and 80 (48%) were male. The median interval between the third and fourth doses was 208·5 days (IQR 203·3–214·8). Pain was the most common local solicited adverse event and fatigue was the most common systemic solicited adverse event after BNT162b2 or mRNA-1273 booster doses. None of three serious adverse events reported after a fourth dose with BNT162b2 were related to the study vaccine. In the BNT162b2 group, geometric mean anti-spike protein IgG concentration at day 28 after the third dose was 23 325 ELISA laboratory units (ELU)/mL (95% CI 20 030–27 162), which increased to 37 460 ELU/mL (31 996–43 857) at day 14 after the fourth dose, representing a significant fold change (geometric mean 1·59, 95% CI 1·41–1·78). There was a significant increase in geometric mean anti-spike protein IgG concentration from 28 days after the third dose (25 317 ELU/mL, 95% CI 20 996–30 528) to 14 days after a fourth dose of mRNA-1273 (54 936 ELU/mL, 46 826–64 452), with a geometric mean fold change of 2·19 (1·90–2·52). The fold changes in anti-spike protein IgG titres from before (day 0) to after (day 14) the fourth dose were 12·19 (95% CI 10·37–14·32) and 15·90 (12·92–19·58) in the BNT162b2 and mRNA-1273 groups, respectively. T-cell responses were also boosted after the fourth dose (eg, the fold changes for the wild-type variant from before to after the fourth dose were 7·32 [95% CI 3·24–16·54] in the BNT162b2 group and 6·22 [3·90–9·92] in the mRNA-1273 group).Interpretation Fourth-dose COVID-19 mRNA booster vaccines are well tolerated and boost cellular and humoral immunity. Peak responses after the fourth dose were similar to, and possibly better than, peak responses after the third dose

From memory to antifungal vaccine design

Fungal infections and related diseases have a high morbidity and mortality rate. Human antifungal vaccines are therefore of great interest, however, their development is challenging. Major hurdles include fungal species-specific differences in pathogenic mechanisms and strategies to escape immune surveillance, as well as the fact that individuals susceptible to infection do not necessarily share the same risk factors. Progress in antifungal vaccines demands the integration of immunology with systems biology, immunogenetics and bioinformatics in the arena of both fungal and host biology. Bridging the fields of basic immunology and vaccine research is needed to create individualized host immune profiles that will direct the rational development of customized adjuvants and vaccines with a predicted efficacy in each target population.Specific Targeted Research Project “FUNMETA” (FP7− ERC−2009−293714 to R.L.

Small Molecule CCR4 Antagonists Protect Mice from Aspergillus Infection and Allergy

International audienceThe ability to regulate the recruitment of immune cells makes chemokines and their receptors attractive drug targets in many inflammatory diseases. Based on its preferential expression on T helper type 2 (Th2) cells, CC chemokine receptor type 4 (CCR4) has been widely studied in the context of allergic diseases, but recent evidence on the expression of CCR4 in other cell types has considerably expanded the potential applications of CCR4 antagonism. However, the current number of approved indications, as well as the portfolio of CCR4-targeting drugs, are still limited. In the present study, we have assessed the potential therapeutic efficacy of a CCR4 small molecule antagonist, SP50, discovered via an in silico-based approach, against a variety of pre-clinical settings of infection with the fungus Aspergillus fumigatus. We show that SP50 efficiently worked as prophylactic vaccine adjuvant in immunocompetent mice, protected against invasive aspergillosis in immunosuppressed mice. Further, the CCR4 antagonist prevented allergic bronchopulmonary aspergillosis in susceptible mice, and in a murine model of cystic fibrosis, a genetic disorder characterized by chronic pulmonary inflammation and recurrent infections. In conclusion, our results extend the potential applications of CCR4 antagonism and prompt for the development of novel compounds with the potential to progress to clinical trials

Distinct and complementary roles for Aspergillus fumigatus-specific Tr1 and Foxp3+Foxp3^+ regulatory T cells in humans and mice

Unlike induced $Foxp3^+$ regulatory T cells ($Foxp3^+$ $iT_{reg}$) that have been shown to play an essential role in the development of protective immunity to the ubiquitous mold Aspergillus fumigatus, type-(1)-regulatory T cells (Tr1) cells have, thus far, not been implicated in this process. Here, we evaluated the role of Tr1 cells specific for an epitope derived from the cell wall glucanase Crf-1 of A. fumigatus (Crf-1/p41) in antifungal immunity. We identified Crf-1/p41-specific latent-associated $peptide^+$ Tr1 cells in healthy humans and mice after vaccination with Crf-1/p41+zymosan. These cells produced high amounts of interleukin (IL)-10 and suppressed the expansion of antigen-specific T cells in vitro and in vivo. In mice, in vivo differentiation of Tr1 cells was dependent on the presence of the aryl hydrocarbon receptor, c-Maf and IL-27. Moreover, in comparison to Tr1 cells, $Foxp3^+$ $iT_{reg}$ that recognize the same epitope were induced in an interferon gamma-type inflammatory environment and more potently suppressed innate immune cell activities. Overall, our data show that Tr1 cells are involved in the maintenance of antifungal immune homeostasis, and most likely play a distinct, yet complementary, role compared with $Foxp3^+$ $iT_{reg}$