Impaired upper respiratory tract barrier function during postnatal development predisposes to invasive pneumococcal disease.

Infants are highly susceptible to invasive respiratory and gastrointestinal infections. To elucidate the age-dependent mechanism(s) that drive bacterial spread from the mucosa, we developed an infant mouse model using the prevalent pediatric respiratory pathogen, Streptococcus pneumoniae (Spn). Despite similar upper respiratory tract (URT) colonization levels, the survival rate of Spn-infected infant mice was significantly decreased compared to adults and corresponded with Spn dissemination to the bloodstream. An increased rate of pneumococcal bacteremia in early life beyond the newborn period was attributed to increased bacterial translocation across the URT barrier. Bacterial dissemination in infant mice was independent of URT monocyte or neutrophil infiltration, phagocyte-derived ROS or RNS, inflammation mediated by toll-like receptor 2 or interleukin 1 receptor signaling, or the pore-forming toxin pneumolysin. Using molecular barcoding of Spn, we found that only a minority of bacterial clones in the nasopharynx disseminated to the blood in infant mice, indicating the absence of robust URT barrier breakdown. Rather, transcriptional profiling of the URT epithelium revealed a failure of infant mice to upregulate genes involved in the tight junction pathway. Expression of many such genes was also decreased in early life in humans. Infant mice also showed increased URT barrier permeability and delayed mucociliary clearance during the first two weeks of life, which corresponded with tighter attachment of bacteria to the respiratory epithelium. Together, these results demonstrate a window of vulnerability during postnatal development when altered mucosal barrier function facilitates bacterial dissemination.

Comparison of the immunogenicity and protective efficacy of ACAM2000, MVA, and vectored subunit vaccines for Mpox in rhesus macaques.

The 2022-2023 mpox outbreak triggered vaccination efforts using smallpox vaccines that were approved for mpox, including modified vaccinia Ankara (MVA; JYNNEOS), which is a safer alternative to live replicating vaccinia virus (ACAM2000). Here, we compare the immunogenicity and protective efficacy of JYNNEOS by the subcutaneous or intradermal routes, ACAM2000 by the percutaneous route, and subunit Ad35 vector-based L1R/B5R or L1R/B5R/A27L/A33R vaccines by the intramuscular route in rhesus macaques. All vaccines provided robust protection against high-dose intravenous mpox virus challenge with the current outbreak strain, with ACAM2000 providing near complete protection and JYNNEOS and Ad35 vaccines providing robust but incomplete protection. Protection correlated with neutralizing antibody responses as well as L1R/M1R- and B5R/B6R-specific binding antibody responses, although additional immune responses likely also contributed to protection. This study demonstrates the protective efficacy of multiple vaccine platforms against mpox virus challenge, including both current clinical vaccines and vectored subunit vaccines.

Waning immunity and IgG4 responses following bivalent mRNA boosting.

Messenger RNA (mRNA) vaccines were highly effective against the ancestral SARS-CoV-2 strain, but the efficacy of bivalent mRNA boosters against XBB variants was substantially lower. Here, we show limited durability of neutralizing antibody (NAb) responses against XBB variants and isotype switching to immunoglobulin G4 (IgG4) responses following bivalent mRNA boosting. Bivalent mRNA boosting elicited modest XBB.1-, XBB.1.5-, and XBB.1.16-specific NAbs that waned rapidly within 3 months. In contrast, bivalent mRNA boosting induced more robust and sustained NAbs against the ancestral WA1/2020 strain, suggesting immune imprinting. Following bivalent mRNA boosting, serum antibody responses were primarily IgG2 and IgG4 responses with poor Fc functional activity. In contrast, a third monovalent mRNA immunization boosted all isotypes including IgG1 and IgG3 with robust Fc functional activity. These data show substantial immune imprinting for the ancestral spike and isotype switching to IgG4 responses following bivalent mRNA boosting, with important implications for future booster designs and boosting strategies.

Mucosal boosting enhances vaccine protection against SARS-CoV-2 in macaques.

A limitation of current SARS-CoV-2 vaccines is that they provide minimal protection against infection with current Omicron subvariants1,2, although they still provide protection against severe disease. Enhanced mucosal immunity may be required to block infection and onward transmission. Intranasal administration of current vaccines has proven inconsistent3-7, suggesting that alternative immunization strategies may be required. Here we show that intratracheal boosting with a bivalent Ad26-based SARS-CoV-2 vaccine results in substantial induction of mucosal humoral and cellular immunity and near-complete protection against SARS-CoV-2 BQ.1.1 challenge. A total of 40 previously immunized rhesus macaques were boosted with a bivalent Ad26 vaccine by the intramuscular, intranasal and intratracheal routes, or with a bivalent mRNA vaccine by the intranasal route. Ad26 boosting by the intratracheal route led to a substantial expansion of mucosal neutralizing antibodies, IgG and IgA binding antibodies, and CD8+ and CD4+ T cell responses, which exceeded those induced by Ad26 boosting by the intramuscular and intranasal routes. Intratracheal Ad26 boosting also led to robust upregulation of cytokine, natural killer, and T and B cell pathways in the lungs. After challenge with a high dose of SARS-CoV-2 BQ.1.1, intratracheal Ad26 boosting provided near-complete protection, whereas the other boosting strategies proved less effective. Protective efficacy correlated best with mucosal humoral and cellular immune responses. These data demonstrate that these immunization strategies induce robust mucosal immunity, suggesting the feasibility of developing vaccines that block respiratory viral infections.

Racial Disparities in Plasma Cell Leukemia Outcomes Among Hospitalized Patients in the United States.

Plasma cell leukemia (PCL) is a rare, aggressive subtype of multiple myeloma (MM) with a poor prognosis. Prior studies have shown that racial disparities affect MM patients in various ways, which may affect patients' outcomes. In this study, we aimed to investigate racial differences in hospitalization outcomes for PCL using Nationwide Inpatient Sample data. Overall, hospitalization rates for PCL tended to decrease over the past decade. Among hospitalized patients with a primary diagnosis of PCL, there was no statistically significant association between race/ethnicity and hospitalization rates, between NH-White patients and NH-Black patients (OR 1.94; 95%CI 0.3-3.54, p 0.95), and Hispanic patients (OR 0.47; 95% CI 0.05-4.23, p 0.5). Additionally, there was no significant association between race/ethnicity and inpatient mortality. The overall lower incidence of PCL, more significant disease burden, and poor prognosis across all groups may contribute to our findings. With increasing evidence that PCL is cytogenetically distinct from MM, more investigation into biological and sociodemographic factors that affect healthcare utilization and treatment outcomes should be carried out.

Mpox infection protects against re-challenge in rhesus macaques.

The mpox outbreak of 2022-2023 involved rapid global spread in men who have sex with men. We infected 18 rhesus macaques with mpox by the intravenous, intradermal, and intrarectal routes and observed robust antibody and T cell responses following all three routes of infection. Numerous skin lesions and high plasma viral loads were observed following intravenous and intradermal infection. Skin lesions peaked on day 10 and resolved by day 28 following infection. On day 28, we re-challenged all convalescent and 3 naive animals with mpox. All convalescent animals were protected against re-challenge. Transcriptomic studies showed upregulation of innate and inflammatory responses and downregulation of collagen formation and extracellular matrix organization following challenge, as well as rapid activation of T cell and plasma cell responses following re-challenge. These data suggest key mechanistic insights into mpox pathogenesis and immunity. This macaque model should prove useful for evaluating mpox vaccines and therapeutics.

Effects of Capsular Polysaccharide amount on Pneumococcal-Host interactions.

Among the many oral streptococci, Streptococcus pneumoniae (Spn) stands out for the capacity of encapsulated strains to cause invasive infection. Spread beyond upper airways, however, is a biological dead end for the organism, raising the question of the benefits of expending energy to coat its surface in a thick layer of capsular polysaccharide (CPS). In this study, we compare mutants of two serotypes expressing different amounts of CPS and test these in murine models of colonization, invasion infection and transmission. Our analysis of the effect of CPS amount shows that Spn expresses a capsule of sufficient thickness to shield its surface from the deposition of complement and binding of antibody to underlying epitopes. While effective shielding is permissive for invasive infection, its primary contribution to the organism appears to be in the dynamics of colonization. A thicker capsule increases bacterial retention in the nasopharynx, the first event in colonization, and also impedes IL-17-dependent clearance during late colonization. Enhanced colonization is associated with increased opportunity for host-to-host transmission. Additionally, we document substantial differences in CPS amount among clinical isolates of three common serotypes. Together, our findings show that CPS amount is highly variable among Spn and could be an independent determinant affecting host interactions.

Enzymatic Characterization of a Novel HSL Family IV Esterase EstD04 from Pseudomonas sp. D01 in Mealworm Gut Microbiota.

Pseudomonas sp. D01, capable of growing in tributyrin medium, was isolated from the gut microbiota of yellow mealworm. By using in silico analyses, we discovered a hypothesized esterase encoding gene in the D01 bacterium, and its encoded protein, EstD04, was classified as a bacterial hormone-sensitive lipase (bHSL) of the type IV lipase family. The study revealed that the recombinant EstD04-His(6x) protein exhibited esterase activity and broad substrate specificity, as it was capable of hydrolyzing p-nitrophenyl derivatives with different acyl chain lengths. By using the most favorable substrate p-nitrophenyl butyrate (C4), we defined the optimal temperature and pH value for EstD04 esterase activity as 40 °C and pH 8, respectively, with a catalytic efficiency (kcat/Km) of 6.17 × 103 mM-1 s-1 at 40 °C. EstD04 demonstrated high stability between pH 8 and 10, and thus, it might be capably used as an alkaline esterase in industrial applications. The addition of Mg2+ and NH4+, as well as DMSO, could stimulate EstD04 enzyme activity. Based on bioinformatic motif analyses and tertiary structural simulation, we determined EstD04 to be a typical bHSL protein with highly conserved motifs, including a triad catalytic center (Ser160, Glu253, and His283), two cap regions, hinge sites, and an oxyanion hole, which are important for the type IV enzyme activity. Moreover, the sequence analysis suggested that the two unique discrete cap regions of EstD04 may contribute to its alkali mesophilic nature, allowing EstD04 to exhibit extremely distinct physiological properties from its evolutionarily closest esterase.

Booster with Ad26.COV2.S or Omicron-adapted vaccine enhanced immunity and efficacy against SARS-CoV-2 Omicron in macaques.

Omicron spike (S) encoding vaccines as boosters, are a potential strategy to improve COVID-19 vaccine efficacy against Omicron. Here, macaques (mostly females) previously immunized with Ad26.COV2.S, are boosted with Ad26.COV2.S, Ad26.COV2.S.529 (encoding Omicron BA.1 S) or a 1:1 combination of both vaccines. All booster vaccinations elicit a rapid antibody titers increase against WA1/2020 and Omicron S. Omicron BA.1 and BA.2 antibody responses are most effectively boosted by vaccines including Ad26.COV2.S.529. Independent of vaccine used, mostly WA1/2020-reactive or WA1/2020-Omicron BA.1 cross-reactive B cells are detected. Ad26.COV2.S.529 containing boosters provide only slightly higher protection of the lower respiratory tract against Omicron BA.1 challenge compared with Ad26.COV2.S-only booster. Antibodies and cellular immune responses are identified as complementary correlates of protection. Overall, a booster with an Omicron-spike based vaccine provide only moderately improved immune responses and protection compared with the original Wuhan-Hu-1-spike based vaccine, which still provide robust immune responses and protection against Omicron.

Ad26.COV2.S and SARS-CoV-2 spike protein ferritin nanoparticle vaccine protect against SARS-CoV-2 Omicron BA.5 challenge in macaques.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines demonstrate reduced protection against acquisition of BA.5 subvariant but are still effective against severe disease. However, immune correlates of protection against BA.5 remain unknown. We report the immunogenicity and protective efficacy of vaccine regimens consisting of the vector-based Ad26.COV2.S vaccine and the adjuvanted spike ferritin nanoparticle (SpFN) vaccine against a high-dose, mismatched Omicron BA.5 challenge in macaques. The SpFNx3 and Ad26 + SpFNx2 regimens elicit higher antibody responses than Ad26x3, whereas the Ad26 + SpFNx2 and Ad26x3 regimens induce higher CD8 T cell responses than SpFNx3. The Ad26 + SpFNx2 regimen elicits the highest CD4 T cell responses. All three regimens suppress peak and day 4 viral loads in the respiratory tract, which correlate with both humoral and cellular immune responses. This study demonstrates that both homologous and heterologous regimens involving Ad26.COV2.S and SpFN vaccines provide robust protection against a mismatched BA.5 challenge in macaques.

Waning Immunity Against XBB.1.5 Following Bivalent mRNA Boosters.

The SARS-CoV-2 Omicron variant has continued to evolve. XBB is a recombinant between two BA.2 sublineages, XBB.1 includes the G252V mutation, and XBB.1.5 includes the G252V and F486P mutations. XBB.1.5 has rapidly increased in frequency and has become the dominant virus in New England. The bivalent mRNA vaccine boosters have been shown to increase neutralizing antibody (NAb) titers to multiple variants, but the durability of these responses remains to be determined. We assessed humoral and cellular immune responses in 30 participants who received the bivalent mRNA boosters and performed assays at baseline prior to boosting, at week 3 after boosting, and at month 3 after boosting. Our data demonstrate that XBB.1.5 substantially escapes NAb responses but not T cell responses after bivalent mRNA boosting. NAb titers to XBB.1 and XBB.1.5 were similar, suggesting that the F486P mutation confers greater transmissibility but not increased immune escape. By month 3, NAb titers to XBB.1 and XBB.1.5 declined essentially to baseline levels prior to boosting, while NAb titers to other variants declined less strikingly.

Protection against SARS-CoV-2 Omicron BA.1 variant challenge in macaques by prime-boost vaccination with Ad26.COV2.S and SpFN.

Emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants and waning immunity call for next-generation vaccine strategies. Here, we assessed the immunogenicity and protective efficacy of two SARS-CoV-2 vaccines targeting the WA1/2020 spike protein, Ad26.COV2.S (Ad26) and Spike ferritin Nanoparticle (SpFN), in nonhuman primates, delivered as either a homologous (SpFN/SpFN and Ad26/Ad26) or heterologous (Ad26/SpFN) prime-boost regimen. The Ad26/SpFN regimen elicited the highest CD4 T cell and memory B cell responses, the SpFN/SpFN regimen generated the highest binding and neutralizing antibody responses, and the Ad26/Ad26 regimen generated the most robust CD8 T cell responses. Despite these differences, protective efficacy against SARS-CoV-2 Omicron BA.1 challenge was similar for all three regimens. After challenge, all vaccinated monkeys showed significantly reduced peak and day 4 viral loads in both bronchoalveolar lavage and nasal swabs as compared with sham animals. The efficacy conferred by these three immunologically distinct vaccine regimens suggests that both humoral and cellular immunity contribute to protection against SARS-CoV-2 Omicron challenge.

Immunogenicity of the BA.5 Bivalent mRNA Vaccine Boosters.

Waning immunity following mRNA vaccination and the emergence of SARS-CoV-2 variants has led to reduced mRNA vaccine efficacy against both symptomatic infection and severe disease. Bivalent mRNA boosters expressing the Omicron BA.5 and ancestral WA1/2020 Spike proteins have been developed and approved, because BA.5 is currently the dominant SARS-CoV-2 variant and substantially evades neutralizing antibodies (NAbs). Our data show that BA.5 NAb titers were comparable following monovalent and bivalent mRNA boosters.

California's experience with SMA newborn screening: A successful path to early intervention.

BACKGROUND: Universal spinal muscular atrophy (SMA) newborn screening was implemented in California on June 24, 2020. OBJECTIVE: We describe California's experience with the first 18 months of SMA newborn screening, including our assay methodology, timeliness of screening and follow-up milestones, and clinical and epidemiological outcomes observed. METHODS: Dried blood spots are screened for SMA using multiplex real time polymerase chain reaction (RT-PCR) to detect deletions of exon 7 in the survival of motor neuron 1 (SMN1) gene. Short-term follow-up data is collected from clinical staff via an online data collection tool. RESULTS: In the first 18 months, 628,791 newborns from California's diverse population were tested for SMA. Thirty-four screened positive and were confirmed to have the disorder. Infants were referred, diagnosed, and treated at a median of 8, 12, and 33 days of life, respectively. Nearly all infants received the desired treatment modality, and 62% received treatment while still asymptomatic. CONCLUSIONS: SMA newborn screening is a highly sensitive and specific test which identifies infants with SMA early when treatment is most effective. Even with newborn screening's success in facilitating early intervention, there is still work to be done to expedite treatment, especially for infants with the most severe form of the disease.

CD8 T cells contribute to vaccine protection against SARS-CoV-2 in macaques.

Spike-specific neutralizing antibodies (NAbs) are generally considered key correlates of vaccine protection against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Recently, robust vaccine prevention of severe disease with SARS-CoV-2 variants that largely escape NAb responses has been reported, suggesting a role for other immune parameters for virologic control. However, direct data demonstrating a role of CD8+ T cells in vaccine protection have not yet been reported. In this study, we show that vaccine-elicited CD8+ T cells contribute substantially to virologic control after SARS-CoV-2 challenge in rhesus macaques. We vaccinated 30 macaques with a single immunization of the adenovirus vector-based vaccine Ad26.COV2.S or sham and then challenged them with 5 × 105 median tissue culture infectious dose SARS-CoV-2 B.1.617.2 (Delta) by the intranasal and intratracheal routes. All vaccinated animals were infected by this high-dose challenge but showed rapid virologic control in nasal swabs and bronchoalveolar lavage by day 4 after challenge. However, administration of an anti-CD8α- or anti-CD8ß-depleting monoclonal antibody in vaccinated animals before SARS-CoV-2 challenge resulted in higher levels of peak and day 4 virus in both the upper and lower respiratory tracts. These data demonstrate that CD8+ T cells contribute substantially to vaccine protection against SARS-CoV-2 replication in macaques.

Vaccine protection against the SARS-CoV-2 Omicron variant in macaques.

The rapid spread of the SARS-CoV-2 Omicron (B.1.1.529) variant, including in highly vaccinated populations, has raised important questions about the efficacy of current vaccines. In this study, we show that the mRNA-based BNT162b2 vaccine and the adenovirus-vector-based Ad26.COV2.S vaccine provide robust protection against high-dose challenge with the SARS-CoV-2 Omicron variant in cynomolgus macaques. We vaccinated 30 macaques with homologous and heterologous prime-boost regimens with BNT162b2 and Ad26.COV2.S. Following Omicron challenge, vaccinated macaques demonstrated rapid control of virus in bronchoalveolar lavage, and most vaccinated animals also controlled virus in nasal swabs. However, 4 vaccinated animals that had moderate Omicron-neutralizing antibody titers and undetectable Omicron CD8+ T cell responses failed to control virus in the upper respiratory tract. Moreover, virologic control correlated with both antibody and T cell responses. These data suggest that both humoral and cellular immune responses contribute to vaccine protection against a highly mutated SARS-CoV-2 variant.

Vaccines elicit highly conserved cellular immunity to SARS-CoV-2 Omicron.

The highly mutated SARS-CoV-2 Omicron (B.1.1.529) variant has been shown to evade a substantial fraction of neutralizing antibody responses elicited by current vaccines that encode the WA1/2020 spike protein1. Cellular immune responses, particularly CD8+ T cell responses, probably contribute to protection against severe SARS-CoV-2 infection2-6. Here we show that cellular immunity induced by current vaccines against SARS-CoV-2 is highly conserved to the SARS-CoV-2 Omicron spike protein. Individuals who received the Ad26.COV2.S or BNT162b2 vaccines demonstrated durable spike-specific CD8+ and CD4+ T cell responses, which showed extensive cross-reactivity against both the Delta and the Omicron variants, including in central and effector memory cellular subpopulations. Median Omicron spike-specific CD8+ T cell responses were 82-84% of the WA1/2020 spike-specific CD8+ T cell responses. These data provide immunological context for the observation that current vaccines still show robust protection against severe disease with the SARS-CoV-2 Omicron variant despite the substantially reduced neutralizing antibody responses7,8.

Vaccine Protection Against the SARS-CoV-2 Omicron Variant in Macaques.

BACKGROUND: The rapid spread of the SARS-CoV-2 Omicron (B.1.1.529) variant, including in highly vaccinated populations, has raised important questions about the efficacy of current vaccines. Immune correlates of vaccine protection against Omicron are not known. METHODS: 30 cynomolgus macaques were immunized with homologous and heterologous prime-boost regimens with the mRNA-based BNT162b2 vaccine and the adenovirus vector-based Ad26.COV2.S vaccine. Following vaccination, animals were challenged with the SARS-CoV-2 Omicron variant by the intranasal and intratracheal routes. RESULTS: Omicron neutralizing antibodies were observed following the boost immunization and were higher in animals that received BNT162b2, whereas Omicron CD8+ T cell responses were higher in animals that received Ad26.COV2.S. Following Omicron challenge, sham controls showed more prolonged virus in nasal swabs than in bronchoalveolar lavage. Vaccinated macaques demonstrated rapid control of virus in bronchoalveolar lavage, and most vaccinated animals also controlled virus in nasal swabs, showing that current vaccines provide substantial protection against Omicron in this model. However, vaccinated animals that had moderate levels of Omicron neutralizing antibodies but negligible Omicron CD8+ T cell responses failed to control virus in the upper respiratory tract. Virologic control correlated with both antibody and T cell responses. CONCLUSIONS: BNT162b2 and Ad26.COV2.S provided robust protection against high-dose challenge with the SARS-CoV-2 Omicron variant in macaques. Protection against this highly mutated SARS-CoV-2 variant correlated with both humoral and cellular immune responses.

Impact of lyoprotectors on protein-protein separation in the solid state: Neutron- and X-ray-scattering investigation.

BACKGROUND: Polyhydroxycompounds (PHC) are used as lyoprotectors to minimize aggregation of pharmaceutical proteins during freeze-drying and storage. METHODS: Lysozyme/PHC mixtures with 1:1 and 1:3 (w/w) ratios are freeze-dried from either H2O or D2O solutions. Disaccharides (sucrose and trehalose), monosaccharide (glucose), and sugar alcohol (sorbitol) are used in the study. Small-angle neutron and X-ray scattering (SANS and SAXS) are applied to study protein-protein interaction in the freeze-dried samples. RESULTS: Protein interaction peak in the freeze-dried mixtures has been detected by both SANS (D2O-based samples only) and SAXS (both D2O- and H2O-based). In the 1:1 mixtures, protein separation distances are similar (center-of-mass distance of approx. 31 Å) between all lyoprotectors studied. Mixtures with a higher content of the disaccharides (1:3 ratio) have a higher separation distance of approx 40 Å. The higher separation could reduce protein-protein contacts and therefore be associated with less favourable aggregation conditions. In the 1:3 mixtures with glucose and sorbitol, complex SANS and SAXS/WAXS patterns are observed. The pattern for the glucose sample indicate two populations of lysozyme molecules, while the origin of multiple SAXS peaks in the lysozyme/sorbitol 1:3 mixture is uncertain. CONCLUSIONS: Protein-protein separation distance is determined predominantly by the lyoprotector/protein weight ratio. GENERAL SIGNIFICANCE: Use of SANS and SAXS improves understanding of mechanisms of protein stabilization by sugars in freeze-dried formulations, and provide a tool to verify hypothesis on relationship between protein/protein separation and aggregation propensity in the dried state.