From hit to vial: Precision discovery and development of an imidazopyrimidine TLR7/8 agonist adjuvant formulation.

Vaccination can help prevent infection and can also be used to treat cancer, allergy, and potentially even drug overdose. Adjuvants enhance vaccine responses, but currently, the path to their advancement and development is incremental. We used a phenotypic small-molecule screen using THP-1 cells to identify nuclear factor-κB (NF-κB)-activating molecules followed by counterscreening lead target libraries with a quantitative tumor necrosis factor immunoassay using primary human peripheral blood mononuclear cells. Screening on primary cells identified an imidazopyrimidine, dubbed PVP-037. Moreover, while PVP-037 did not overtly activate THP-1 cells, it demonstrated broad innate immune activation, including NF-κB and cytokine induction from primary human leukocytes in vitro as well as enhancement of influenza and SARS-CoV-2 antigen-specific humoral responses in mice. Several de novo synthesis structural enhancements iteratively improved PVP-037's in vitro efficacy, potency, species-specific activity, and in vivo adjuvanticity. Overall, we identified imidazopyrimidine Toll-like receptor-7/8 adjuvants that act in synergy with oil-in-water emulsion to enhance immune responses.

Carbohydrate fatty acid monosulphate: oil-in-water adjuvant enhances SARS-CoV-2 RBD nanoparticle-induced immunogenicity and protection in mice.

Development of SARS-CoV-2 vaccines that protect vulnerable populations is a public health priority. Here, we took a systematic and iterative approach by testing several adjuvants and SARS-CoV-2 antigens to identify a combination that elicits antibodies and protection in young and aged mice. While demonstrating superior immunogenicity to soluble receptor-binding domain (RBD), RBD displayed as a protein nanoparticle (RBD-NP) generated limited antibody responses. Comparison of multiple adjuvants including AddaVax, AddaS03, and AS01B in young and aged mice demonstrated that an oil-in-water emulsion containing carbohydrate fatty acid monosulphate derivative (CMS:O/W) most effectively enhanced RBD-NP-induced cross-neutralizing antibodies and protection across age groups. CMS:O/W enhanced antigen retention in the draining lymph node, induced injection site, and lymph node cytokines, with CMS inducing MyD88-dependent Th1 cytokine polarization. Furthermore, CMS and O/W synergistically induced chemokine production from human PBMCs. Overall, CMS:O/W adjuvant may enhance immunogenicity and protection of vulnerable populations against SARS-CoV-2 and other infectious pathogens.

An adjuvant strategy enabled by modulation of the physical properties of microbial ligands expands antigen immunogenicity.

Activation of the innate immune system via pattern recognition receptors (PRRs) is key to generate lasting adaptive immunity. PRRs detect unique chemical patterns associated with invading microorganisms, but whether and how the physical properties of PRR ligands influence the development of the immune response remains unknown. Through the study of fungal mannans, we show that the physical form of PRR ligands dictates the immune response. Soluble mannans are immunosilent in the periphery but elicit a potent pro-inflammatory response in the draining lymph node (dLN). By modulating the physical form of mannans, we developed a formulation that targets both the periphery and the dLN. When combined with viral glycoprotein antigens, this mannan formulation broadens epitope recognition, elicits potent antigen-specific neutralizing antibodies, and confers protection against viral infections of the lung. Thus, the physical properties of microbial ligands determine the outcome of the immune response and can be harnessed for vaccine development.

An aluminum hydroxide:CpG adjuvant enhances protection elicited by a SARS-CoV-2 receptor binding domain vaccine in aged mice.

Global deployment of vaccines that can provide protection across several age groups is still urgently needed to end the COVID-19 pandemic, especially in low- and middle-income countries. Although vaccines against SARS-CoV-2 based on mRNA and adenoviral vector technologies have been rapidly developed, additional practical and scalable SARS-CoV-2 vaccines are required to meet global demand. Protein subunit vaccines formulated with appropriate adjuvants represent an approach to address this urgent need. The receptor binding domain (RBD) is a key target of SARS-CoV-2 neutralizing antibodies but is poorly immunogenic. We therefore compared pattern recognition receptor (PRR) agonists alone or formulated with aluminum hydroxide (AH) and benchmarked them against AS01B and AS03-like emulsion-based adjuvants for their potential to enhance RBD immunogenicity in young and aged mice. We found that an AH and CpG adjuvant formulation (AH:CpG) produced an 80-fold increase in anti-RBD neutralizing antibody titers in both age groups relative to AH alone and protected aged mice from the SARS-CoV-2 challenge. The AH:CpG-adjuvanted RBD vaccine elicited neutralizing antibodies against both wild-type SARS-CoV-2 and the B.1.351 (beta) variant at serum concentrations comparable to those induced by the licensed Pfizer-BioNTech BNT162b2 mRNA vaccine. AH:CpG induced similar cytokine and chemokine gene enrichment patterns in the draining lymph nodes of both young adult and aged mice and enhanced cytokine and chemokine production in human mononuclear cells of younger and older adults. These data support further development of AH:CpG-adjuvanted RBD as an affordable vaccine that may be effective across multiple age groups.

Alum:CpG adjuvant enables SARS-CoV-2 RBD-induced protection in aged mice and synergistic activation of human elder type 1 immunity.

Global deployment of vaccines that can provide protection across several age groups is still urgently needed to end the COVID-19 pandemic especially for low- and middle-income countries. While vaccines against SARS-CoV-2 based on mRNA and adenoviral-vector technologies have been rapidly developed, additional practical and scalable SARS-CoV-2 vaccines are needed to meet global demand. In this context, protein subunit vaccines formulated with appropriate adjuvants represent a promising approach to address this urgent need. Receptor-binding domain (RBD) is a key target of neutralizing antibodies (Abs) but is poorly immunogenic. We therefore compared pattern recognition receptor (PRR) agonists, including those activating STING, TLR3, TLR4 and TLR9, alone or formulated with aluminum hydroxide (AH), and benchmarked them to AS01B and AS03-like emulsion-based adjuvants for their potential to enhance RBD immunogenicity in young and aged mice. We found that the AH and CpG adjuvant formulation (AH:CpG) demonstrated the highest enhancement of anti-RBD neutralizing Ab titers in both age groups (∼80-fold over AH), and protected aged mice from the SARS-CoV-2 challenge. Notably, AH:CpG-adjuvanted RBD vaccine elicited neutralizing Abs against both wild-type SARS-CoV-2 and B.1.351 variant at serum concentrations comparable to those induced by the authorized mRNA BNT162b2 vaccine. AH:CpG induced similar cytokine and chemokine gene enrichment patterns in the draining lymph nodes of both young adult and aged mice and synergistically enhanced cytokine and chemokine production in human young adult and elderly mononuclear cells. These data support further development of AH:CpG-adjuvanted RBD as an affordable vaccine that may be effective across multiple age groups. ONE SENTENCE SUMMARY: Alum and CpG enhance SARS-CoV-2 RBD protective immunity, variant neutralization in aged mice and Th1-polarizing cytokine production by human elder leukocytes.

Detailed analysis of Japanese patients with adenosine deaminase 2 deficiency reveals characteristic elevation of type II interferon signature and STAT1 hyperactivation.

BACKGROUND: Deficiency of adenosine deaminase 2 (DADA2) is an autosomal recessive inflammatory disease caused by loss-of-function mutations in both alleles of the ADA2 gene. Most patients with DADA2 exhibit systemic vasculopathy consistent with polyarteritis nodosa, but large phenotypic variability has been reported, and the pathogenesis of DADA2 remains unclear. OBJECTIVES: This study sought to assess the clinical and genetic characteristics of Japanese patients with DADA2 and to gain insight into the pathogenesis of DADA2 by multi-omics analysis. METHODS: Clinical and genetic data were collected from 8 Japanese patients with DADA2 diagnosed between 2016 and 2019. ADA2 variants in this cohort were functionally analyzed by in vitro overexpression analysis. PBMCs from 4 patients with DADA2 were subjected to transcriptome and proteome analyses. Patient samples were collected before and after introduction of anti- TNF-α therapies. Transcriptome data were compared with those of normal controls and patients with other autoinflammatory diseases. RESULTS: Five novel ADA2 variants were identified in these 8 patients and were confirmed pathogenic by in vitro analysis. Anti-TNF-α therapy controlled inflammation in all 8 patients. Transcriptome and proteome analyses showed that upregulation of type II interferon signaling was characteristic of DADA2. Network analysis identified STAT1 as a key regulator and a hub molecule in DADA2 pathogenesis, a finding supported by the hyperactivation of STAT1 in patients' monocytes and B cells after IFN-γ stimulation. CONCLUSIONS: Type II interferon signaling and STAT1 are associated with the pathogenesis of DADA2.

Procalcitonin levels predicting the infliximab response of immunoglobulin resistant Kawasaki disease.

OBJECTIVE: To search the predictive factors of infliximab resistance in intravenous immunoglobulin (IVIG)-resistant Kawasaki disease (KD) patients. STUDY DESIGN: Twenty-seven patients with KD who received infliximab after 4-5 g/kg of IVIG therapy from 2013 to 2015 were consecutively recruited in this study. They were divided into two groups: patients who responded to infliximab (infliximab-responsive group, n = 15) and patients who required additional therapy for the disease control (infliximab-resistant group, n = 12). We analyzed the clinical and laboratory parameters just before the infliximab treatment including serum levels of procalcitonin and cytokines with respect to the infliximab response. RESULTS: Serum procalcitonin concentration (P = 0.017), neutrophils to lymphocytes ratio (P = 0.013), and % neutrophils (P = 0.004) were higher, and serum sodium concentration (P = 0.017) was lower in infliximab-resistant group than those of infliximab-responsive group, respectively. Multivariate logistic regression analyses indicated that higher procalcitonin concentration (odds ratio [OR] 1.48, 95% confidence interval [CI] 1.00-5.00, P = 0.046) and lower sodium levels (OR 0.64, 95% CI 0.32-1.00, P = 0.047), but not other variables, were associated with infliximab-resistance. Serum procalcitonin concentrations positively correlated with the serum levels of interleukin-6, soluble tumor necrosis factor receptor type 1 and type 2, respectively. Analyses of the receiver operating characteristic (ROC) curve showed that the cut-off value of procalcitonin 2.0 ng/ml had 58.3% of sensitivity and 93.3% of specificity. ROC analysis yielded an area under the curve (AUC) of 0.739 to predict infliximab-resistance. CONCLUSION: Serum procalcitonin might be an effective biomarker to predict infliximab resistance in severe KD patients who are refractory to IVIG treatment.

Effective infliximab therapy for the early regression of coronary artery aneurysm in Kawasaki disease.

BACKGROUND: There is limited information available regarding the role of infliximab (IFX) following the acute phase of Kawasaki disease (KD). We aimed to evaluate whether IFX is associated with coronary artery aneurysm (CAA) regression. METHODS: Between 2005 and 2016, we identified 971 consecutive patients with KD from 3 tertiary institutions, and 49 (5%) with CAAs were enrolled in our study. Patients were divided into 2 groups: 27 who received IFX and 22 who did not. The persistence rate of CAAs was compared between the groups. RESULTS: Age, sex, and duration of the febrile period did not significantly differ between the groups. The maximum value of C-reactive protein was higher in the IFX- than in the non-IFX group. The maximum z-score of CAAs did not differ between the groups. The 2-, 4- and 6-year cumulative persistence rate of CAA was 24%, 24% and 24% in IFX-group, whereas 67%, 52% and 33% in non-IFX group, respectively (P = 0.03). The median duration of CAA regression was 1.1 vs. 4.6 years. Among those who developed medium- or large-sized CAAs, the 2-, 4- and 6-year cumulative persistence rate of CAA was 33%, 33% and 33% in IFX group, whereas 77%, 51% and 48% in non-IFX group, respectively (P = 0.047). Multivariate logistic regression analysis indicated that the maximum z-score (hazard ratio 0.72, p < 0.001) and response to IFX (hazard ratio 4.56, p = 0.017) were independently related to regression. CONCLUSION: IFX therapy was observed to be effective for the early improvement of CAAs in patients with intravenous immunoglobulin-resistant KD.

Activation of Nod1 Signaling Induces Fetal Growth Restriction and Death through Fetal and Maternal Vasculopathy.

Intrauterine fetal growth restriction (IUGR) and death (IUFD) are both serious problems in the perinatal medicine. Fetal vasculopathy is currently considered to account for a pathogenic mechanism of IUGR and IUFD. We previously demonstrated that an innate immune receptor, the nucleotide-binding oligomerization domain-1 (Nod1), contributed to the development of vascular inflammations in mice at postnatal stages. However, little is known about the deleterious effects of activated Nod1 signaling on embryonic growth and development. We report that administration of FK565, one of the Nod1 ligands, to pregnant C57BL/6 mice induced IUGR and IUFD. Mass spectrometry analysis revealed that maternally injected FK565 was distributed to the fetal tissues across placenta. In addition, maternal injection of FK565 induced robust increases in the amounts of CCL2, IL-6, and TNF proteins as well as NO in maternal, placental and fetal tissues. Nod1 was highly expressed in fetal vascular tissues, where significantly higher levels of CCL2 and IL-6 mRNAs were induced with maternal injection of FK565 than those in other tissues. Using Nod1-knockout mice, we verified that both maternal and fetal tissues were involved in the development of IUGR and IUFD. Furthermore, FK565 induced upregulation of genes associated with immune response, inflammation, and apoptosis in fetal vascular tissues. Our data thus provided new evidence for the pathogenic role of Nod1 in the development of IUGR and IUFD at the maternal-fetal interface.

Memory B-Cell Pools Predict the Immune Response to Pneumococcal Conjugate Vaccine in Immunocompromised Children.

BACKGROUND: The immune responses to pneumococcal conjugate vaccine (PCV) are low in immunocompromised hosts. The effect of memory B cells on the immune response to PCV remains elusive. METHODS: In this prospective study, 53 children who received 7-valent PCV were enrolled. Antipneumococcal immunoglobulin G (IgG) levels and opsonization index (OI) titers, along with lymphocyte subsets, were investigated in immunocompromised and immunocompetent hosts. Immunocompromised patients comprised 8 hematopoietic stem cell transplant recipients (group A) and 9 immunosuppressive therapy recipients (group B), and controls consisted of 14 children aged >1 year (group C) and 22 infants (group D). RESULTS: Serotype-specific IgG concentrations and OIs in group A were lower than those in group C. These did not differ among groups B, C, and D. The rates of achieving immunity (defined as an IgG level of 1.0 µg/mL and an OI of 8) in group A were also lower than in group C. Despite the sustained numbers of total T cells and B cells, CD27(+) B-cell and CD4(+) T-cell counts in group A were lower than those in group C. In group B, the immunoglobulin D-expressing CD27(-) B-cell count was only lower than that in group C. CONCLUSIONS: Circulating numbers of CD27(+) B cells, rather than CD4(+) T cells, may predict the effective PCV responses in immunocompromised children.

Neonatal hemophagocytic lymphohistiocytosis associated with a vertical transmission of coxsackievirus B1.

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening syndrome characterized by fever, cytopenias, hepatosplenomegaly, and coagulopathy with the background of hypercytokinemia. Early diagnosis and etoposide therapy are not established for affected newborns. An afebrile infant suffered from apnea 4 days after birth, showing leukocytosis, thrombocytopenia, coagulopathy, and cerebrospinal fluid pleocytosis. Serum levels of ferritin and sIL-2R were high. Bone marrow studies revealed activated/hemophagocytosing macrophages. Coxsackievirus B1 (CB1) was isolated from the throat and stool. Serum anti-CB1 antibody titers were elevated in the patient (4 â†’ 16; 6 â†’ 43 days after birth) and mother (128; 10 days after delivery). Normal expressions of perforin and CD107a precluded inherited HLH. The vertically transmitted CB1-HLH was successfully treated without administration of corticosteroid, cyclosporine, or etoposide. Serum cytokine levels showed dominant expression of monokines (IL-1ß/6/8, and TNF-α) but not IFN-γ, which is the central player of inherited HLH. The cytokine profile might represent a unique pathophysiology of enterovirus-driven neonatal HLH.